Monday, March 10, 2008

Repair Guide: Lights, Fuses & Flashers

Modern vehicles use dozens of bulbs to light everything from the road to the ashtray. Servicing the system is easy; over half of all lighting problems are caused by burned out bulbs, corroded sockets or burned out fuses.

The first step in understanding a vehicle's lights, fuses and flashers is to learn about basic electricity. For more information on electrical circuits, how they work and how to troubleshoot them, please refer to the information on "Understanding and Troubleshooting Electrical Systems" elsewhere in this manual

Light Bulbs
See Figures 1, 2, 3 and 4

Small bulbs, used for most automotive applications, come in several basic types-single contact bayonet base, double contact bayonet base with opposed or staggered indexing lugs, cartridge types for a small, flat installation, and wedge-base light bulbs.

Small bulbs show a broken filament when burned-out and are easily replaced. Turn them about ¼ turn and pull them from the socket. The single contact bayonet base is usually used for instrument panel lights in a small snap-in socket. The major difficulty in replacing these is finding them.

The double contact bayonet base is commonly used for turn signals, parking and taillights. The staggered indexing lugs allow one-way installation so the filament connection is correct. These bulbs are reached by removing the lens or light assembly; inside the trunk is also a common place to hide the light housings.

Don't forget to install the gasket under the lens or housing, if one is used. The gasket seals out moisture, a major cause of bulb troubles. While the bulb is out of the socket, check the socket for corrosion and if necessary, clean it.

Poor grounding is a major cause of non-functioning bulbs, especially when the bulb filaments are OK. Scraping the terminal sockets and polishing the bulb contacts is frequently all that's required. Also, check the ground between the bulb housing and the fender, and between the fender and the body. The electricity has to get back to the ground (negative) side of the battery. If it can't because of poor grounding, the bulb won't work. Many times, running a ground wire from the bulb housing directly to the frame of the vehicle is easier than trying to make a ground through rusted sheet metal.

Figure 1 Examples of various types of automotive light bulbs

1. Halogen headlight bulb
2. Side marker light bulb 3. Dome light bulb
4. Turn signal/brake light bulb

Figure 2 Burned bulbs show a broken filament (arrows)

Figure 3 Depress and twist this type of bulb counterclockwise, then pull the bulb straight from its socket

Figure 4 Disengage the spring clip which retains one tapered end of this dome light bulb, then withdraw the bulb

See Figures 5 and 6

In the good old days, headlights where the one part for the vehicle that were easy to figure out. They were round sealed beams and you either had two or four mounted on the front of your vehicle. Nothing stays simple very long. New styling brought on rectangular headlights. This alone doubled the number of possibilities. Even more design changes and lowered hood lines brought out the small rectangular and even the mini-quad (the smallest size sealed beam). This brought the possible number of sealed beam configurations to seven.

For years, European vehicles used halogen capsule headlight assemblies. It wasn't until the late 80's that the Department of Transportation (DOT) approved the use for these in U.S. vehicles. This added three new possibilities to the existing sealed beams. However, what this meant to the automaker's was that they could design composite aerodynamic headlight assemblies that could conform to every body design and they can share these common replaceable halogen capsule bulbs.

Practically all late model cars and light trucks use halogen lights. The halogen lights increase the candlepower of the headlight from 75,000 to almost 150,000 and boosts the distance a driver can see at night by almost 20% over the old tungsten lights. Automaker's started installing them on top-of-the-line models in 1980 and they went to wide spread use on 1981 and later models.

Like the old tungsten lights, the halogen lights use a tungsten filament, but it is contained in a halogen gas environment, which allows the filament to be heated to a much higher temperature to produce a much brighter and whiter light. They also require less power, so that a smaller and lighter alternator can be used.

See Figure 5 Common headlight configurations

Figure 6 Light patterns of different types of headlights


See Figures 7, 8, 9 and 10
On most vehicles, light bulb replacement is a simple matter. On sealed beam units, the retaining ring is removed (by loosening the clamp and/or removing the retaining bolts), then the beam is pulled forward so the electrical connector can be unplugged.

Figure 7 To replace most sealed beam headlights, start by loosening the retaining ring fastener(s) . . .

Figure 8 . . . then remove the retaining ring to free the headlight

Figure 9 Pull the lamp forward and unplug the wiring harness, then install the replacement bulb

On most halogen vehicles the bulb is replaced from behind the lamp assembly. Usually it is just a matter of opening the hood, unscrewing the lock ring on the bulb socket and/or the bulb socket itself and withdrawing the assembly from the back of the lamp. Once the socket is exposed you can remove the old halogen bulb and install the replacement.

NEVER touch the glass of a halogen bulb! If you touch the glass, you fingers will leave behind natural skin oils which will create a hot spot on the bulb, burning it out LONG BEFORE the natural end of its life. Most halogen bulbs contain a metallic coated tip which can be safely handled and, of course, you can always handle it by the plastic base.

Figure 10 Most new vehicles require only halogen bulb replacement


See Figures 11, 12, 13 and 14
The headlights must be properly aimed to provide the best, safest road illumination. The lights should be checked for proper aim and adjusted as necessary. Certain state and local authorities have requirements for headlight aiming; these should be checked before adjustment is made.

About once a year, when the headlights are replaced or any time front end work is performed on your vehicle, the headlights should be accurately aimed by a reputable repair shop using the proper equipment. Headlights not properly aimed can make it virtually impossible to see and may blind other drivers on the road, possibly causing an accident. Note that the following procedure is a temporary fix, until you can take your vehicle to a repair shop for a proper adjustment.

Headlight adjustment may be temporarily made using a wall, as described below, or on the rear of another vehicle. When adjusted, the lights should not glare in oncoming car or truck windshields, nor should they illuminate the passenger compartment of vehicles driving in front of you. These adjustments are rough and should always be fine-tuned by a repair shop which is equipped with headlight aiming tools. Improper adjustments may be both dangerous and illegal.

For most of the vehicles, horizontal and vertical aiming of each sealed beam unit is provided by two adjusting screws which move the retaining ring and adjusting plate against the tension of a coil spring. There is no adjustment for focus; this is done during headlight manufacturing.

On vehicles with composite headlights, the assembly is bolted into position, no adjustment should be necessary or possible. Some applications, however, may be bolted to an adjuster plate or may be retained by adjusting screws. If so, follow this procedure when adjusting the lights, BUT always have the adjustment checked by a reputable shop.

Before removing the headlight bulb or disturbing the headlamp in any way, note the current settings in order to ease headlight adjustment upon reassembly. If the high or low beam setting of the old lamp still works, this can be done using the wall of a garage or a building:

  1. Park the vehicle on a level surface, with the fuel tank about ½ full and with the vehicle empty of all extra cargo (unless normally carried). The vehicle should be facing a wall which is no less than 6 feet (1.8m) high and 12 feet (3.7m) wide. The front of the vehicle should be about 25 feet from the wall.
  2. If neither beam on one side is working, and if another like-sized vehicle is available, park the second one in the exact spot where the vehicle was and mark the beams using the same-side light. Then switch the vehicles so the one to be aimed is back in the original spot. It must be parked no closer to or farther away from the wall than the second vehicle.
  3. Perform any necessary repairs, but make sure the vehicle is not moved, or is returned to the exact spot from which the lights were marked. Turn the headlights ON and adjust the beams to match the marks on the wall.
  4. Have the headlight adjustment checked as soon as possible by a reputable repair shop.
  5. If aiming is to be performed outdoors, it is advisable to wait until dusk in order to properly see the headlight beams on the wall. If done in a garage, darken the area around the wall as much as possible by closing shades or hanging cloth over the windows.
  6. Turn the headlights ON and mark the wall at the center of each light's low beam, then switch on the brights and mark the center of each light's high beam. A short length of masking tape which is visible from the front of the vehicle may be used. Although marking all four positions is advisable, marking one position from each light should be sufficient.

Figure 11 Location of the aiming screws on most vehicles with sealed beam headlights

Figure 12 Example of headlight adjustment screw location for composite headlamps

Figure 13 Low-beam headlight pattern alignment

Figure 14 High-beam headlight pattern alignment

Repair Guide: Fasteners (Part 2 of 2)


There is a variety of nuts used on vehicles. Slotted and castle (castellated) nuts are designed for use with a cotter pin. These are mainly used for various suspension and wheel bearing fasteners, where it is extremely important that the nuts do not work loose.

Other nuts have a self - locking feature. A soft metal or plastic collar inside the nut is slightly smaller than the bolt threads. When the nut is turned down, the bolt cuts a thread in the collar and the collar material jams in the bolt threads to keep the nut from loosening.

Still other varieties of nuts include jam nuts and speed nuts. A jam nut is merely a second nut which is tightened against the first nut in order to hold the first nut in place. Jam nuts are widely used where an adjustment is involved. A speed nut is a rectangular piece of sheet metal that is pushed down over a screw or stud.


A lockwasher is a split or toothed washer. It is usually installed between a nut or screw head, and a flat washer or the actual part and is used to help keep a nut or screw from loosening in service. The split washer is crushed flat and locks the nut in place by spring tension, while the toothed lockwasher, usually used for smaller bolts, provides many edges to improve the locking effect.

Cotter Pins

Cotter pins are used with slotted or castle nuts to lock the nut in position (preventing it from loosening or coming off in service). When used, the stud or bolt has a hole in it. When the nut is tightened, you align the slots with the hole so that a pin can be inserted. After the cotter pin is inserted through the nut and bolt, the legs of the cotter pin are bent over to lock the pin in place.

Loosening Seized Nuts and Bolts

See Figure 15
Occasionally, nuts and bolts that are rusted resist the ministrations of mere mortals and refuse to budge. Most of the time, penetrating oil or a sharp rap with a hammer will loosen stubborn nuts.

Another method, used in extreme cases, is to saw away two sides of the nut with a hacksaw. The idea is to weaken the nut as much as possible by sawing away two sides as close to the bolt as possible without actually damaging the bolt threads. A wrench will usually remove the remaining portion of the nut. Another option to this method is a special tool called a nutcracker. This tool often resembles a "C" - clamp with a chisel tip (other versions of this tool may be completely round with a tip at the opposite end of the threaded portion). Tightening this tool against the nut splits the nut and it then can be easily removed with a wrench. Figure 15 "C"-clamp type nut cracker (top) and impact driver (bottom) can be used to remove stubborn nuts and bolts

Removing Broken Bolts
See Figure 16

Unfortunately for the do - it - yourselfer learning the feel for how tight is too tight is an acquired skill. Breaking bolts is an unfortunate learning experience for most new mechanics. Most often, the original threads are still in satisfactory condition, however there is no longer any means to turn the bolt. When this occurs you can try to drill the bolt out and rethread the hole using a tap. However, this would probably cause you to go to the next size bolt.

The more common method to remove a broken bolt is a tool called a bolt extractor, often referred to as an Easy - Out®. Bolt extractors are available in various shapes and sizes, and are often sold in kits. You will need to know the original bolt size to select the correct tool. Once selected you will drill a small hole in the center of the bolt. Then you will insert and lightly tap the tool into the hole until it is snug. Finally, you can turn the tool and hopefully the remains of the bolt removing them from the hole. Figure 16 Bolt or screw extractors come in a variety of shapes and sizes

Repairing Damaged Threads
See Figures 17, 18, 19, 20 and 21

Several methods of repairing damaged threads are available. Heli - Coil®(shown here), Keenserts® and Microdot® are among the most widely used. All involve the same principle - drilling out stripped threads, tapping the hole and installing a pre - wound insert - making welding, plugging and oversize fasteners unnecessary.

Two types of thread repair inserts are usually supplied - a standard type for most inch - coarse, inch - fine, metric - coarse and metric - fine thread sizes and a spark plug type to fit most spark plug port sizes. Consult the individual manufacturer's catalog to determine exact applications. Typical thread repair kits will contain a selection of pre - wound threaded inserts, a tap (corresponding to the outside diameter threads of the insert) and an installation tool. Spark plug inserts usually differ because they require a tap equipped with pilot threads and a combined reamer/tap section. Most manufacturers also supply blister - packed thread repair inserts separately plus a master kit containing a variety of taps and inserts plus installation tools.

Before effecting a repair to a threaded hole, remove any snapped, broken or damaged bolts or studs. Penetrating oil can be used to free frozen threads; the offending item can be removed with locking pliers or with a screw or stud extractor. After the hole is clear, the thread can be repaired. Figure 17 Damaged bolt holes can be repaired with thread with thread repair inserts

Figure 18 Drill out the damaged threads with the specified bit. Drill completely through the hole or to the bottom of the blind hole.

Figure 19 With the tap supplied, rethread the hole to receive the threaded insert. Keep the tap well oiled and back the tap out frequently to avoid clogging the threads.

Figure 20 Screw the thread insert onto the thread installation tool until the tang engages the slot. Screw the insert into the tapped hole until it is ¼-½ turn below the top surface. After installation break the tang off with a hammer and punch.

Figure 21 In some cases threads can be restored by running a tap in the hole, or a die on the bolt

Repair Guide: Fasteners (Part 1 of 2)

See Figure 1

In most applications, fasteners on vehicles may be reused providing they have not been damaged during a repair. However, in certain special applications where stretch bolts or torque prevailing nuts are used these fasteners must be replaced.

Threaded fasteners are the basic couplers holding your vehicle together. There are many different kinds, but they all fall into three basic types:

Bolts - Bolts go through holes in parts that are attached together and require a nut that is turned onto the other end. A lock - washer of some sort is usually used under the nut.
Studs - Studs are similar to bolts, except that they are threaded at both ends (they have no heads). One end is screwed into a threaded hole and a nut is turned onto the other end. Lock - washers are usually used under the nuts.
Screws - Screws are turned into drilled or threaded holes in metal or other materials.

There are a great variety of screws and bolts, but most are hex headed or slot headed for tightening. Because the fastener is the weakest link in an assembly, it is useful to know the relative strength of the fastener, determined by the size and type of material. It is also important to understand the sizes of bolts, to avoid the expense and work of re - threading stripped holes. Figure 1 Keep an assortment of fasteners and hardware neatly sorted in tackle boxes


See Figures 2 and 3
Screws are supplied with slotted, Phillips, Torx® or Allen heads for screwdrivers or with hex heads for wrenches. Most of the screws used on cars and trucks are sheet metal, hexagon or pan type. Occasionally, you'll find a self - tapping sheet metal screw, with slots in the end to form a cutting edge. These types cut their own threads when turned into a hole.

The size of a screw is designated as 8-32, 10-32 or ¼-32. The first number indicates the size of the thread at the root or minor diameter (the diameter of the screw measured from the bottom of the threads on each side) and the second number indicates the number of threads per inch. Figure 2 Common screw and bolt head types

Figure 3 Screw and bolt measurement terms

Torx® Fasteners

See Figure 4
Torx® fasteners have a star shaped head of either an internal or an external design.

These fasteners come in three different types. The most common being internal, these fasteners require a star shaped driver and are frequently found on headlight retainers and adjusters. The second type is external, these fasteners require a star shaped socket and may be found in odd locations such as the wheel cylinder retaining bolts. The third type is tamper resistant, which are used in places that manufacturer's are very serious about avoiding a Do - It - Yourselfer (DIYer) from touching. These look similar to the internal type however, they have a pin in the center of the fastener preventing the use of the standard Torx® driver. They may be found on components that are meant to be serviced only by authorized repair centers. Figure 4 Two different types of Torx® fasteners.

SAE Bolts

See Figures 5, 6 and 7
Many bolts that were once used on domestic cars and trucks maybe measured in inches, and standards for these bolts were established by the Society of Automotive Engineers (SAE). Special markings on the head of the bolt indicate its tensile strength (resistance to breaking). The SAE grade number, corresponding to the special markings, is an indication of the relative strength of the bolt. Grade 0 bolts (no markings) are usually made of a mild steel and are much weaker than a grade 8, usually made from a mild carbon steel alloy, though a grade 0 or 2 bolt is sufficient for most fasteners.

SAE fasteners are also identified by size. As an example, a 3/8-24 bolt means that the major (greatest) thread diameter is 3/8 inch and that there are 24 threads per inch. The head diameter is always 316inch larger than the bolt diameter. A ½16 bolt would be ½ inch in diameter and have 16 threads per inch. More threads per inch are called "fine" threads and less threads per inch are "coarse" threads. Generally, the larger the bolt diameter, the coarser the threads. There are actually six different classes of threads, but most bolts are Unified National Coarse (UNC) or Unified National Fine (UNF). The term "Unified" refers to a thread pattern to which US, British and Canadian machine screw threads conform. Figure 5 Fasteners commonly found on automobiles

Figure 6 SAE bolt head markings indicate their relative strength

See Figure 7 SAE standard torque specification chart.

Metric Bolts

See Figures 8 thru 14
The International Standards Organization (ISO) has designated the metric system as the world standard of measurement.

As far back as the early 1970's when Ford introduced the 2300cc, 4 - cylinder engine in the Pinto, the use of metric fasteners have become more prevalent in domestic vehicles. Probably the majority of domestic vehicles on the road today have more metric fasteners than the inch - size (SAE) type and almost all the fasteners on vehicles currently being produced are metric.

The mixture of metric and SAE fasteners on the same vehicle means that you have to be very careful when removing bolts to note their locations and to keep metric nuts and bolts together. At first glance, metric fasteners may appear to be the same size as their SAE counterparts, but they're not. While the size may be very close, the pitch of the threads (distance between threads) is different. It is possible to start a metric bolt into a hole with SAE threads and run it down several turns before it binds. Any further tightening will strip the threads. The opposite could occur also; a nut could be run all the way down and be too loose to provide sufficient strength.

Fortunately, metric bolts are marked differently than SAE bolts. An ISO metric bolt larger than 6 mm in diameter has either "ISO M" or "M" embossed on top of the head. In addition, most metric bolts are identified by a number stamped on the bolt head, such as 4.6, 5.8 or 10.9. The number has nothing to do with the size, but does indicate the relative strength of the bolt. The higher the number, the stronger the bolt. Some metric nuts are also marked with a single - digit number to indicate the strength, and some may have the M and strength grade embossed on the flats of the hex.

Metric nuts with an ISO thread are marked on one face of the hex flats with the strength grade (4, 5, 6, 8, 12, and 14). Some nuts with a 4, 5 or 6 strength grade may or may not be marked.

A clock face system is used as an alternate means of strength grade designation. The external chamfers or faces of the nut are marked with a dash at the appropriate hour mark corresponding to the relative strength grade. One dot indicates the 12 o'clock position and, if the grade is above 12, 2 dots identify 12 o'clock.

The size of a metric fastener is also identified differently than an SAE fastener. A metric fastener could be designated M12 x 2, for example. This means that the major diameter of the threads is 12 mm and that the thread pitch is 2 mm (there are 2 mm between threads). Most importantly, metric threads are not classed by number of threads per inch, but by the distance between the threads, and the distance between threads does not exactly correspond to number of threads per inch (2 mm between threads is about 12.7 threads per inch).

The 25 standard metric diameter and pitch combinations are shown here. The first number in each size is the nominal or root (minor) diameter (mm) and the second number is the thread pitch (mm).

Remember that the nominal bolt diameter is the measurement of the bolt diameter as taken from the bottom of the threads NOT the top (which would be major diameter). Figure 8 A thread gauge will instantly identify the thread size

Figure 9 Metric grade to SAE grade comparison
Metric Grade Nominal Diameter (mm) Corresponds to SAE Grade
4.6 M5 thru M36 1
4.8 M1.6 thru M16 -
5.8 M5 thru M24 2
8.8 M16 thru M36 5
9.8 M1.6 thru M16 -
10.9 M5 thru M36 8
12.9 M1.6 thru M36 -

Figure 10 Metric bolts are marked with numbers that indicate the relative strength of the bolt. These numbers have nothing to do with the size of the bolt.

Figure 11 Typical ISO bolt and nut markings

Figure 12. The 25 standard metric diameter and pitch combinations
25 Standard Metric Diameter and Pitch Combinations
M1.6 x 0.35 M20 x 2.5
M2 x 0.4 M24 x 3
M2.5 x 0.45 M30 x 3.5
M3 x 0.5 M36 x 4
M3.5 x 0.6 M42 x 4.5
M4 x 0.7 M48 x 5
M5 x 0.8 M56 x 5.5
M6.3 x 1.0 M64 x 6
M8 x 1.25 M72 x 6
M10 x 1.5 M80 x 6
M12 x 1.75 M90 x 6
M14 x 2 M100 x 6

Figure 13 Thread forms replaced by ISO Metric

Metric Size

- - 10 10 M5
3/16 3/16 - - -
- - 12 12 M6
1/4 1/4 1/4 1/4 M6
5/16 5/16 5/16 5/16 M8
3/8 3/8 3/8 3/8 M10
7/16 7/16 7/16 7/16
1/2 1/2 1/2 1/2 M12

Buyer's Guide to Parts and Supplies (Part 2 of 2)

Sources for Parts

There are many sources for the parts you will need. Where you shop for parts will be determined by what kind of parts you need, how much you want to pay, and the types of stores in your neighborhood.


New vehicle dealers usually have parts for your vehicle, but the prices are usually higher than other sources. The dealer carries what are known in the auto trade as Original Equipment Manufacturer (OEM) parts. OEM parts are those supplied by the vehicle manufacturer and are the same parts installed on the vehicle when it was built. Because of the higher overhead expenses, these parts are generally a little more expensive than the same item available through other outlets.
The higher cost of OEM parts does not necessarily indicate a better value, or higher quality. Automotive jobbers and auto discount stores regularly stock high - quality replacement parts in addition to OEM parts. Although manufacturers will recommend that you use OEM parts for replacement or service work, they will also specify that you can use an equivalent replacement part. Many replacement parts are made by or sold by reputable companies and are built to the same specifications as OEM parts. In many cases, replacement parts may even be identical to OEM parts, since many parts manufacturers sell parts to vehicle makers as OEM parts and also sell the same part to other companies, who market the part under a different brand name. The parts you have to be careful of are "gypsy" parts, which are discussed later in this section. Fortunately there are very few of them.

There are some parts for your vehicle - cylinder heads, crankshafts, body parts, and other slow movers - that you will be unlikely to obtain anywhere but at your dealer. These parts are not sold in sufficient quantities to make it attractive for any other outlet to stock them. Many of these parts may be special ordered.


Your local service station can supply you with many of the common parts you require; though they stock these parts mainly for their own use in the repair end of the business. The problem, from the consumer's standpoint, is the cost - it will be high. The reason is that the service station operator buys the same part from a jobber that you can buy over the counter. Although he buys at a discount, he must make a profit on the resale of the item, whether through direct sale of the item or as part of repair charges. Really, when your service station sells parts to you over the counter, they are competing with the local parts stores and discount merchandisers, and most service stations do not buy or sell parts in sufficient volume to offer a competitive price. They are in business to sell "service," not to sell parts.


The local parts jobber, who is usually listed in the yellow pages or whose name can be obtained from the local gas station, supplies most of the parts that are purchased by service stations and repair shops. He also does a sizeable business in over - the - counter parts sales for the do - it - yourselfer, and this may constitute as much as 30% to 50% of his business.
The jobber usually has at least two prices - one for the local mechanic or service station and an over - the - counter retail price. The reason for this is that local mechanic, like the service station, does not pay the retail price for a given part. They pay less than retail (a mechanic's discount may range from 15-40% depending on the item) and mark up the price of the part to their customer, making a profit on the resale. Many jobbers will offer you a 10%-15% discount off the retail prices on over - the - counter sales, and most jobbers run periodic sales on both private brand and brand name do - it - yourself items.

The prices charged by jobbers are usually lower than the new vehicle dealers and service stations but slightly higher than discount or mass merchandisers. The reason is that the jobber is used to dealing with professional mechanics and usually sells name brand or OEM parts. His volume is such that he sells more than a service station, but less than a discount merchandiser does, and thus his prices fall somewhere between the two. The people who work the counters in the jobber stores and discount stores know about vehicles - often more than the salesperson in the auto section of a department store. Unless they are extremely busy or very rushed, they can usually offer valuable advice on quality parts or tools needed to do the job right.


Almost every community has one or more convenient automotive chain stores. These stores often offer the best retail prices and the convenience of one - stop shopping for all your automotive needs. Since they cater to the automotive do - it - yourselfer, these stores are almost always - open weekday nights, Saturdays, and Sundays, when the automotive jobbers are usually closed.
Chain stores are the automotive "supermarkets." Hardly a week goes by that they are not running advertised specials or a seasonal promotion of some type. The ads normally appear in the local newspapers and offer substantial savings on both name and store brand items. In contrast to the traditional jobber stores, where most merchandise is located behind the counter, you can walk through the auto chain stores and browse among most products, picking and choosing from a large stock of brand names.

Prices in the auto chain stores will normally be competitive with the discount stores and mass merchandisers, and they will usually be slightly lower than the jobber will. Counter personnel working in the chain and jobber stores are usually familiar with their products and common automotive problems and can offer good advice.


The lowest prices for parts are most often found in discount stores or the auto department of mass merchandisers, such as K - Mart, Sears, and Wal - Mart. Parts sold here are name and private brand parts bought in huge quantities, so they can offer a competitive price. Private brand parts are made by major manufacturers and sold to large chains under a store label.
You have to have a good idea of what you're looking for when you buy from these outlets. Many are self - serve, in direct contrast to the older, traditional jobbers where they still look up the part number and get the part for you.


Wrecking yards, junkyards, salvage yards, previously owned parts yards - call them what you will - are good sources of parts, particularly for older vehicles or limited budgets, although most parts available from salvage yards are beyond the scope of this book. Auto wrecking yards range from the incredibly sophisticated computer - run inventories to stumblebum one - man operations where nobody knows exactly what they have except the inevitable snarling dog.
In most cases, don't expect the wrecking yards to supply the smaller parts. They prefer to deal in complete assemblies. Among the better deals in wrecking yards are engines, transmissions, rear axles, body parts, and wheels. The cost of these parts from a yard is generally about one - half the cost of new parts. Most junkyards are not interested in selling carburetors, voltage regulators, and other small parts, but if they do, their cost will be negligibly less than the cost of rebuilt parts, and rebuilt parts are a far better deal.

Some wrecking yards may have two prices - one if they remove the parts and one if you do it. Most yards will prefer to remove parts themselves, but be careful. Time is money when removing parts, so a lot of yards, particularly the less organized, will remove an engine or rear axle with a cutting torch instead of unbolting it. This makes it necessary for you to buy small parts, such as motor mounts, brake lines, spring hangers, and other hardware, that were destroyed by the cutting torch.

Kinds of Parts


Many times, you will be required to return your old starter, alternator, fuel pump, or carburetor when you buy a new one. These old parts are returned to a professional parts rebuilding service and are reconditioned to be sold over the counter as remanufactured or rebuilt parts.
Most parts stores will carry both new and rebuilt parts. There is nothing wrong with buying remanufactured parts. Many are just as good as the new ones but can be bought at considerable savings. Compare the price and guarantee on a remanufactured part with that of a new part. In general, the higher the quality of a remanufactured part, the closer the price will be to a new part and the better the warranty.

Inordinately low prices for remanufactured parts usually mean shorter parts life and earlier failures. In this case, it will be worthwhile to spend a little extra money for higher quality.


Caveat Emptor - let the buyer beware - was a reasonable attitude when the buyer could easily judge the quality of the merchandise he was buying.
However, as automobiles have become increasingly sophisticated, with electronic engine control systems and other hi - tech hardware, there are fewer manifestly clear ways by which to judge the quality of replacement parts.

Reputable manufacturers of replacement parts have built their reputations of repeat business. Their products meet or exceed the Original Equipment (OE) specifications. If they don't perform, you're not going to come back and buy many more of the same. Counterfeiting, as applied to auto parts, is a broad term that covers any form of deception designed to trick the buyer into believing that he or she is purchasing a part produced by the original equipment manufacturer or a reputable aftermarket manufacturer.

Counterfeit products should not be confused with "generic or no - brand" products such as those found in the food industry. It's fully understood that these types of products are not branded products. The key to counterfeit parts lies in the fact that no attempt is made to identify the source of manufacture and that the counterfeit part and packaging closely resembles the real thing.

Packaging of reputable parts manufacturers is often unique and highly recognizable, but those who buy replacement parts by appearance or packaging alone should beware. Counterfeit parts are made to look like the real thing both in packaging and in appearance.

Counterfeit packaging usually involves the unauthorized use of a registered trademark on the packaging or the simulation of a part using original equipment characteristics and is designed to pass off generally sub - standard parts as the genuine article. Counterfeit parts have the right number of wires and connectors. They look official, durable and reliable.

However, looks are deceiving. Not only can counterfeit parts cost you money in the long run, due to premature failure or an unknown manufacturer who will not guarantee the part's performance, the shortcuts often taken in the manufacture of counterfeit parts could jeopardize your safety or the vehicle's performance. Some counterfeit brake shoes have been found deficient in braking power. Some counterfeit gas tank caps have no safety valves, designed to prevent spillage and fire in case of an accident.

How can you recognize counterfeit parts? Often, it's extremely difficult.

Buy brand - name products. A name brand manufacturer's reputation for quality can only have been earned by selling quality merchandise.
Be suspicious of packaging that very closely, but not exactly, replicates the packaging of a known, name brand manufacturer.
Recognize that in a competitive marketplace, there will be variations in price among reputable manufacturers. Nevertheless, be suspicious of extremely low prices.
If someone other than you is installing the part, ask to see the package in which it came. Even mechanics are not immune to assuming, mistakenly, that they are buying name brand replacement parts.
If possible, compare the original equipment part with the replacement part before purchasing the replacement part. There are often subtle differences between counterfeit and original equipment and reputable replacement parts.

Using Automotive Catalogs
See Figure 1

To a person looking for a part for his or her vehicle, the catalog is the most important tool to know how to use. Automotive parts catalogs are what you make them - a confusing foreign language or an easy - to - understand reference to get the correct part number, and price the first time.

Almost all manufacturers of hard parts make a catalog listing the part number, application, and sometimes the price of the item. The catalog may take the form of a large book with thousands of entries if the manufacturer makes many parts for a lot of applications, or it may be as simple as a single card if the manufacturer has relatively few variations. If you are purchasing oil filters, air filters, PCV valves, belts, hoses, and similar common parts, you will usually find the catalog near the merchandise in the parts store, though from time to time they will disappear. Wherever they are located and whatever form they take, learning to use them will assure that you get the correct part the first time, saving a lot of time and energy to return parts that don't fit.

With the age of computer databases, more and more parts look - up is done via a terminal on the parts counter. It is important to supply the operator with the correct information regarding your vehicle as discussed earlier. He will enter the vehicle only one time and have access to many different manufactures parts, as opposed to looking up the vehicle, then the part in individual printed catalogs. You may also find mini - computers in product locations on the sales floor for filters, batteries, wiper blades, etc. Figure 1 Parts catalogs, giving part number and application, are provided by manufacturers for most replacement parts


Catalogs normally contain a descriptive and dated (sometimes - coded) cover, a table of contents, index, illustrations, and then the meat of the catalog, the applications. The applications are normally arranged two ways: (l) alphabetically by vehicle name, and (2) numerically by part number. Jobbers may store their catalogs using the Weatherly filing system, a three - digit number on the front of the catalog, but this is of little interest to the do - it - yourselfer. What does interest you is the alphabetical listing of vehicles by make and model.
Many manufacturers print their parts catalogs every year, but some only print every two years and supply a supplement during the off year. It is essential to check the date of the catalog to be sure it has the latest information. Working with an outdated catalog is sometimes worse than working with no catalog at all.


Let's say you want to look up the spark plug for your 1996 Jeep Cherokee with a 4.0L engine. The first thing you do is find a spark plug catalog and check the date to make sure it is current. Then you look in the index for "Jeep." In this particular catalog, there is no listing by make and model in the index. The spark plug applications are broken down by Automobiles, Vans / Trucks & Buses, and several other listings. If you have an SUV or sport utility vehicle it may be listed either in the Car or Automobile section or in the Truck section depending upon the manufacturer. In this case, turn to the page starting Vans, Trucks & Buses.
Under Vans, Trucks & Buses, you'll find they are broken down into individual makes starting with Acura and working back to Volkswagen. Scan the pages until you find the heading Jeep. Under Jeep, you'll find the applications are further broken by model and year. And then 4 - cylinder and 6 - cylinder engines. Your Jeep is a 1996 Cherokee and has a 6 - cylinder, so look under the appropriate heading. Read across the column from the L6 4.0L entry and find the number of the spark plug.


See Figure 2
If you have trouble deciphering the abbreviations used in the parts catalog, they are usually identified in the front of the catalog.

The biggest distraction in all automotive catalogs is the footnotes. Asterisks, daggers, numerals, and letters that appear after a part number or listing indicate that you are up against a footnote. If such a notation is present, you must look further for more information. Most likely, you will go to the bottom of the page for an explanation of why the notation was used. In addition, the explanation could be almost anything. Special kits, superceded parts, special applications, and a myriad of other pieces of information all are deserving of footnotes. To get the right part for your vehicle you cannot afford to skip over the footnotes. Figure 2 Catalog footnotes are important. They may contain replacement part numbers and other pertinent information.


See Figure 3
Many catalogs include a cross - reference so you can double check information. A cross - reference could be from original equipment to independent supplier part numbers, or to application by part number.

Caution should be used when cross - referencing parts. While Original Equipment Manufacturer (OEM) to an aftermarket part number is often a very accurate reference, aftermarket - to - aftermarket references should be double - checked by that particular manufactures application guide.

Figure 3 It is a good idea to check the actual number on the part, against the application catalog.


Catalogs are designed for using, not confusing, but it is not unusual for catalog users to make mistakes in tracking down part numbers. Simple goofs are the most common and costly. For instance, often the user will find the correct listing, but then he or she reads across the wrong line. On the other hand, sometimes everything is done correctly, but a mistake is made in copying or trying to remember the part number. Alternatively, you can be mixed up in using a cross - reference, or working with an outdated catalog, or overlooking a footnote. Such mistakes happen every day to even the most experienced. All you can do is try your best to avoid them.

Buyer's Guide to Parts and Supplies (Part 1 of 2)

See Figure 1
Do - it - yourself has become an economic necessity for many of us. It's an opportunity to save some money and have some measure of fun working on the old buggy at the same time.

You'll find, if you haven't already, that it's easy to change the oil and filters or handle minor repairs, but you have to be sure you're getting the correct parts, at the best price.

Today, manufacturers and retailers know you're interested in do - it - yourself repairs to save money. That's why you'll find parts packaged or displayed with application charts to help you select the right parts for your vehicle.

Auto supply stores, discount and department stores, automotive jobbers, and other sources sell complete lines of quality parts for auto repair enthusiasts like you. You may want to comparison shop these outlets to see where you can get the most for your money. It's wise to compare price tags and quality all year, instead of expecting to find bargains on infrequent shopping tours. Sales on replacement parts are common. Weekly specials, holiday, and seasonal promotions all offer a chance to save on your automotive needs.

It doesn't really matter whether you buy name brand or store - brand parts. You can save a little money on the store - brand items as opposed to Original Equipment Manufacture (OEM) parts, but you may end up replacing them a little sooner if you buy too far down on the price scale.

The main thing is to be sure to get the correct part for your vehicle. An incorrect part can adversely affect your engine performance, fuel economy, and emissions, and will cost you more money and aggravation in the end. To avoid buying the parts piecemeal, many manufacturers have taken to offering do - it - yourself tune-up packages, containing, plugs, rotor, and sometimes distributor cap. Spark plug wires can be purchased already cut to length and ready to install, or as a kit, in which case you cut the necessary lengths yourself.

To get the proper parts for your vehicle, you will probably need to know some or all of the following information:

  • Make: Jeep, Saturn, etc.
  • Model: Cherokee, SL2 Sedan, etc.
  • Year: 1996 (example)
  • Engine size: The engine size may be designated in cubic inches (242, 116, etc.) or in cubic centimeters (cc) on imports (1600, 2000, etc.). Usually, it will be given in liters (4.0, 1.9, etc.). If you are not sure, there is usually a designation on the engine or under the hood that tells you the engine size. There may be a letter with the number that you should copy down, too. When in doubt write down all the information you can find it will save you repeated trips to the parts store.
  • Number of cylinders: 4, 5, 6, 8, etc., for example
  • Carburetor (or fuel injection): If the engine is carbureted, you'll need to know if the carburetor is a 1, 2, 3, or 4 barrel (abbreviated bbl) model. You may also find the word venturi (abbreviated V) used interchangeably with the word barrel when describing carburetors. On fuel injected models you may need to know which injection system is used. This is important because there are instances where a given model in the same year may have two engines with the same displacement, and the only difference may be the injection system. These are usually described on the engine in some sort of acronym SFI, SPFI, MFI, PGMFI, etc. In addition, your fuel - injected engine may be turbo - charged. These conditions will usually have ramifications that will effect other engine and fuel related parts.
  • Air conditioner: Yes or No
  • Quantity of oil: How many quarts
  • Engine code: Since 1981, this code has been important to all domestic and some import vehicles. The engine code is part of the 17 digit Vehicle Identification Number (VIN), which is visible through the front windshield on the driver's side. On GM, Ford and Chrysler vehicles, the engine code is the 8th digit. On many import vehicles the engine must be identified by a tag on the engine or a number stamped on the block, bell housing or other location.

Figure 1 Make copies of this chart and keep with your vehicle


For quick and easy reference, you can use this form to Jot down frequently used information concerning parts available for your vehicle.

Tune-Up Data
Firing Order
Spark Plugs:

Type (Manufacturer/No.)

Gap (in./mm)

Ignition Timing
Vacuum (Connected/Disconnected)
Valve Clearance (in./mm) Exhaust

Engine Oil (qts/litres)

With Filter Change

Type of Lubricant Cooling System (qts/litres)

Manual Transmission (pts/litres)

Type of Lubricant

Transfer Case (pts/litres)

Type of Lubricant

Automatic Transmission (pts/litres)

Type of Lubricant

Differential (pts/litres)

Type of Lubricant

Commonly Forgotten Part Numbers
Use these spaces to record the part numbers of frequently replaced parts.
Part No.

Part No.
Part No.
Part No.

Repair Guide: Tools and Supplies (Part 3 of 3)

Jacks and Jackstands
See Figures 46, 47, 48 and 49

A vehicle must be raised in order to lubricate the chassis, change the oil and gain access to various parts under the vehicle. Above all, a vehicle must be raised and supported safely. Never attempt to work under a vehicle supported only by a jack.

The jack that comes with the vehicle is suitable for raising the vehicle, but is not suitable for supporting the vehicle while you work under it. Once the vehicle is raised, place safety stands under it before attempting any work.

Scissors jacks are the least expensive types of jacks. These are mechanically operated by a threaded rod that is turned inside a diamond-shaped frame. Cranking the screw causes the diamond-shaped frame to expand or contract, raising or lowering the vehicle.

Hydraulic jacks are the best and quickest means of lifting a vehicle off the ground. Hydraulic jacks run anywhere from $30–$300, depending on the size and quality of the jack. They are available as small units that can be picked up easily in one hand and placed where needed, or as large, heavy units equipped with wheels to move them about. The smaller models work slowly and tip over easier.

Hydraulic jacks use a pump to push hydraulic fluid against a ram that operates the lifting pad. They have seals that are prone to leaking. This is one good reason why you shouldn't work under a vehicle supported by a hydraulic jack. If the seals leak, the jack will lose pressure and the vehicle will slowly (or quickly) fall to the ground.

Jackstands are the safest way to support a vehicle. They are made of heavy metal, and are adjustable for different working levels. Once you have raised the vehicle to a convenient height, the Jackstands are adjusted underneath it and the vehicle is lowered onto the stands. Professional Jackstands are the easiest to use, but cost the most. Occasionally, if you're very fortunate, they can be picked up used from a service station that is going out of business.

Drive-on ramps are the alternative to jacking and supporting the vehicle. A good set of pressed steel ramps can cost as much as $40–$70, but they are often worth the expense. Be sure to check the angle of the incline on the ramps. With extensive use of front spoilers and air dams on today's vehicles, often there may be clearance problems.

Fig. 46 A hydraulic floor jack and a set of jackstands are essential for lifting and supporting the vehicle

Fig. 47 Car ramps may substitute for a jack and jackstands, however, old style ramps don't provide adequate clearance for late-model vehicles...

Fig. 48 style ramps have angle adapters to allow clearance for front spoilers on many of today's vehicles.

Fig. 49 When using ramps or jackstands, always block the wheels on the opposite end of the vehicle

Shop Supplies
See Figures 50 and 51

When you plan your shop supplies, you should follow the same format as you used for your tools- if you intend to perform only basic level work, you need only acquire a minimum number of supplies, and so forth.

At the basic level, you're going to need mostly replacement fluids. Things such as motor oil, antifreeze, automatic transmission fluid and brake fluid should be kept on hand. You'll also need some clean rags or wiping towels and some hand cleaner.

At the average level, things get a little more complex. You'll probably need chassis and wheel bearing grease, spare hoses and belts, plugs, penetrating oil, parts cleaner and a variety of other supplies.

The list of supplies needed for the advanced level could be endless, but if you're operating at the advanced level, you probably already have most supplies. Look at the list prepared here, keeping in mind that it's only a partial list, and these are all just suggestions. Remember the advanced level includes all the other levels as well.

Fig. 50 Hand cleaners have gone high-tech! Lotion, cream, and even citrus. Make sure you have some on hand.

Fig. 51 Shop sealants and adhesives come in a variety of applications. Always read the package before use.


See Figures 52, 53, and 54
If you're not already familiar with the terms "aerobic," "anaerobic" and "RTV", you probably should be. These are the kinds of sealant that have replaced many cork and rubber gaskets on vehicle assemblies.

The terms refer to the curing properties of the sealant. Aerobic means that the sealant cures in the presence of air and can be used on flexible flanges and between machined parts. However, it should not be used where it might squeeze out and plug small passages. Parts must be assembled immediately or the sealant will harden.

RTV sealant is another name for a type of aerobic sealant, standing for Room Temperature Vulcanizing. Aerobic sealants are often identified as RTV silicone rubber compounds, under names such as GM, GE, Permatex®, Devcon®, Dow Corning, MOPAR®, FelPro®, Loctite®, or Versa Chem®.

Anaerobic sealants are those that cure in the absence of air. In other words, the sealant will not cure (harden) until the parts are assembled and the air is denied. Anaerobic sealants are for use between smooth, machined surfaces, but should not be used between flexible mounting flanges. They should also be applied sparingly in a continuous bead to a clean surface.

Uncured aerobic or RTV sealants can be wiped off with a rag. Cured sealants can be removed with a scraper, wire brush or common shop solvents. Fig. 52 Anaerobic sealant is available in several types from a variety of manufacturers

Fig. 53 Epoxy systems are available for metal and plastics and have different drying times

Fig. 54 RTV comes in various colors indicating specific applications. Once again read the package.

Universal Thread Sealant

There are more thread sealants than can be counted. Add to these the several sealant tapes now on the market and the confusion can be great. Mechanics should be aware of the anaerobic sealant with Teflon® filler that can be used on all joints. (GM Truck has adopted it as universal sealant.) "Pipe Sealant with Teflon" is applied to threads. It creates an instant seal, but does not cure for 24 hours. This permits making changes if needed. Once hardened it prevents vibration-induced loosening.

How to Use Sealants

Anaerobics: Clean surfaces with solvent and apply bead to one surface. Material will not begin to cure until parts are assembled. Sealing is effective in half an hour. Full cure is complete in 2½–10 hours depending upon temperature. Cold slows cure.

Aerobic or Silicone sealants: Clean and dry surfaces. Apply bead and let cure for two hours. To make a gasket that will cling to only one surface, apply bead to one surface and allow it to cure. Then apply grease to other surface, and assemble. Or, to make a gasket that will bond to both surfaces, apply and assemble. This will provide maximum blowout resistance. Material will cure to depth of ¼ inch in 24 hours.

When to Use Sealants

The basic guide in choosing a sealant is the size of the gap. Anaerobic materials are used only on smooth, rigid, machine-surfaced flanges which have a total gap less than .030 inch (.301mm). Silicones are used in parts that may flex (such as metal-stamping covers) and which have gaps that are more than .030 inch (.301mm) but not more than 0.25 inch (6.35mm). Both materials are impervious to the normal automotive fluids such as gas, oil, coolants and hydraulics. Anaerobics have a temperature range of - 60–300F (15–149°C), and silicones will handle- 100– 450°F (38–232°C).

Anaerobics: Common applications for the anaerobic materials include fuel pumps, timing covers, oil pumps, water pumps, thermostat housings, oil filter adapters, manual transmission housings, differential covers and other rigid parts. Bear in mind that anaerobic materials add rigidity to the assembly because they help lock the surfaces.

Aerobic or Silicone sealants: Many silicone applications involve stamped metal housings such as oil pans, valve covers, and other parts such as intake manifolds, transmission covers, axle covers and rear main bearing seals.

Solvent release: Non-hardening sealants are used to repair cut gaskets on both rigid and flexible assemblies that operate at high temperatures up to 600°F (315°C). On semi-permanent assemblies, the materials set quickly to bolster the conventional gasket. By remaining pliable, they permit easy removal later.

Hardening sealants dry fast and hard and are used on permanent assemblies to aid the conventional gasket, particularly when the flanges are damaged.

Most sealants also aid in assembly by holding the gasket in place during assembly. When such positioning problems are extremely difficult, a gasket adhesive can be used to hold the gasket in perfect alignment during assembly.

Arranging Your Shop
See Figure 55

Obviously, the arrangement of your shop depends a great deal on just what kind of shop you have in the first place. If you have very limited floor space, careful use of wall space will be the key to allowing yourself working room. If you're like most of us, you probably have a million things in the garage already, which isn't going to help matters. Put up some shelves or get some pegboard to hang tools on. Make sure you have plenty of lighting in the garage. If you don't have enough lights, install some more. There's nothing worse than trying to work by the light of a flashlight or a trouble light. Keep the floor clean and make sure you have adequate ventilation. Keep flammable liquids outside, and anchor all the benches and any heavy equipment you may have. Fig. 55 One vehicle and two vehicle typical shop layout

Servicing Your Vehicle Safely
See Figures 56 and 57

It is virtually impossible to anticipate all of the hazards involved with automotive maintenance and service, but care and common sense will prevent most accidents.

The rules of safety for mechanics range from "don't smoke around gasoline," to "use the proper tool for the job." The trick to avoiding injuries is to develop safe work habits and take every possible precaution.


  • Do keep a fire extinguisher and first aid kit handy.
  • Do wear safety glasses or goggles when cutting, drilling, grinding or prying, even if you have 20–20 vision. If you wear glasses for the sake of vision, wear safety goggles over your regular glasses.
  • Do shield your eyes whenever you work around the battery. Batteries contain sulfuric acid. In case of contact with the eyes or skin, flush the area with water or a mixture of water and baking soda, then seek immediate medical attention.
  • Do use safety stands (jackstands) for any undervehicle service. Jacks are for raising vehicles; jackstands are for making sure the vehicle stays raised until you want it to come down. Whenever the vehicle is raised, block the wheels remaining on the ground and set the parking brake.
  • Do use adequate ventilation when working with any chemicals or hazardous materials. Like carbon monoxide, the asbestos dust resulting from some brake lining wear can be hazardous in sufficient quantities.
  • Do disconnect the negative battery cable when working on the electrical system. The secondary ignition system contains EXTREMELY HIGH VOLTAGE. In some cases it can even exceed 50,000 volts.
  • Do follow manufacturer's directions whenever working with potentially hazardous materials. Most chemicals and fluids are poisonous if taken internally.
  • Do properly maintain your tools. Loose hammerheads, mushroomed punches and chisels, frayed or poorly grounded electrical cords, excessively worn screwdrivers, spread wrenches (open end), cracked sockets, slipping ratchets, or faulty droplight sockets can cause accidents. Likewise, keep your tools clean; a greasy wrench can slip off a bolt head, ruining the bolt and often harming your knuckles in the process.
  • Do use the proper size and type of tool for the job at hand. Do select a wrench or socket that fits the nut or bolt. The wrench or socket should sit straight, not cocked.
  • Do, when possible, pull on a wrench handle rather than push on it, and adjust your stance to prevent a fall.
  • Do be sure that adjustable wrenches are tightly closed on the nut or bolt and pulled so that the force is on the side of the fixed jaw.
  • Do strike squarely with a hammer; avoid glancing blows.
  • Do set the parking brake and block the drive wheels if the work requires a running engine.


  • Don't run the engine in a garage or anywhere else without proper ventilation- EVER! Carbon monoxide is poisonous; it takes a long time to leave the human body and you can build up a deadly supply of it in your system by simply breathing in a little every day. You may not realize you are slowly poisoning yourself. Always use power vents, windows, fans and/or open the garage door.
  • Don't work around moving parts while wearing loose clothing. Short sleeves are much safer than long, loose sleeves. Hard-toed shoes with neoprene soles protect your toes and give a better grip on slippery surfaces. Jewelry such as watches, fancy belt buckles, beads or body adornment of any kind is not safe working around a vehicle. Long hair should be tied back under a hat or cap.
  • Don't use pockets for toolboxes. A fall or bump can drive a screwdriver deep into your body. Even a rag hanging from your back pocket can wrap around a spinning shaft or fan.
  • Don't smoke when working around gasoline, cleaning solvent or other flammable material.
  • Don't smoke when working around the battery. When the battery is being charged, it gives off explosive hydrogen gas.
  • Don't use gasoline to wash your hands; there are excellent soaps available. Gasoline contains dangerous additives which can enter the body through a cut or through your pores. Gasoline also removes all the natural oils from the skin so that bone dry hands will suck up oil and grease.
  • Don't service the air conditioning system unless you are equipped with the necessary tools and training. When liquid or compressed gas refrigerant is released to atmospheric pressure it will absorb heat from whatever it contacts. This will chill or freeze anything it touches. Although refrigerant is normally non-toxic, R-12 becomes a deadly poisonous gas in the presence of an open flame. One good whiff of the vapors from burning refrigerant can be fatal.
  • Don't use screwdrivers for anything other than driving screws! A screwdriver used as an prying tool can snap when you least expect it, causing injuries. At the very least, you'll ruin a good screwdriver.
  • Don't use a bumper or emergency jack (that little ratchet, scissors, or pantograph jack supplied with the vehicle) for anything other than changing a flat! These jacks are only intended for emergency use out on the road; they are NOT designed as a maintenance tool. If you are serious about maintaining your vehicle yourself, invest in a hydraulic floor jack of at least a 112 ton capacity, and at least two sturdy jackstands.

Fig. 56 Always support your vehicle on jackstand while working underneath

Fig. 57 If you're using portable electric tools, make sure they're grounded, preferably at the plug by a three wire connector



Repair Guide: Tools and Supplies (Part 2 of 3)

Specialty Tools
See Figures 20 thru 28

In addition to basic tools, you'll find a number of small specialty tools that will make your life as a do-it-yourselfer much easier. A battery terminal puller (for top terminal batteries) costs only a few bucks, and will save you a lot of trouble when you remove your battery cables. A combination cable and terminal cleaner is also handy. A tire pressure gauge is an absolute must if you plan to get the most wear out of your tires. Buy a good one, since tire pressure is critical to tire life. An antifreeze hydrometer is necessary to keep an eye on the state of your coolant. Fig. 20 Side terminal battery cleaning tool

Fig. 21 Battery terminal puller

Fig. 22 Top battery terminal cleaning tool

Fig. 23 Tire pressure gauges top, and tread depth gauges bottom

Fig. 24 A hydrometer is necessary to check antifreeze protection

Fig. 25 Tools from specialty manufacturers such as Lisle and Cal-Van are designed to make your job easier. Here is an assortment of brake tools.

Fig. 26 Specialty sockets are required for many sensors and axle nuts. Acquire these as the job calls for it.

Fig. 27 Special pullers are required for various applications. Often these tools can be rented from a tool rental or auto parts store.

Fig. 28 Interior door handles and panels often require special clip removers

General Maintenance Tools

The list of general maintenance tools is practically endless, depending on the degree of your involvement. However, a basic list for the average do-it-yourself mechanic would include:

  • An oil filter wrench,
  • A grease gun,
  • A container for draining oil,
  • A suction gun,
  • Battery terminal cleaners, and
  • Many rags for cleaning up the inevitable mess.

Oil filter wrenches come in various types. The strap wrench is the most common and will handle most filters. A more sophisticated filter wrench combines a strap or band wrench with a ratchet drive. This type is useful when the filter is located in an out-of-the-way place. Many oil filters on front wheel drive vehicles, can only be removed with this type of wrench. The other types of filter wrenches are applied to the end of the oil filter, and both are designed for use with a ratchet drive.

A funnel is the best way to get oil from the bottle into the engine with a minimum of mess. Any other way will surely result in oil spilled on the engine, which will turn to smoke when the engine gets hot. Other types of fillers have flexible spouts for filling automatic transmissions and other hard-to-reach filler tubes.

A grease gun is also the only way to lubricate the vehicle's chassis. The grease gun comes in various sizes that accept cartridges of different kinds of grease and a variety of flexible and odd-shaped fittings to reach hard-to-get-at grease nipples.

A fluid suction gun is almost a necessity to add (or remove) oil from a differential. The filler plugs on differentials and manual transmissions are frequently in a spot that you cannot fill directly from the container. You will probably have to transfer the fluid from the container into a suction gun first. The fluid is also frequently heavy oil, which does not flow easily, which further complicates the problem. To remove fluid from a unit without a drain plug, a suction gun is invaluable.

Battery cleaning tools are inexpensive and make battery terminal cleaning easier and quicker. They generally come in two styles, one for top terminals and one for side terminals. The one for side terminals is nothing more than a miniature wire brush, which you can easily substitute. Fig. 29 Oil filter wrenches come in a number of styles. You will have to experiment to find the correct combination for your vehicle.

Fig. 30 Lubrication tools- suction gun, grease gun, and bearing packers

Fig. 31 This type of oil drain pan enables you to take your waste oil to a recycling station. Remember to drain the filter into the pan.

Tune-Up Tools

The word "tune-up" actually applies only to older vehicles, on which you can perform the traditional work associated with "tune-up"- spark plug replacement, ignition contact point replacement, dwell adjustment, ignition timing adjustment and carburetor idle and mixture adjustment.

For today's vehicles, engine performance maintenance is a more accurate term. Modern vehicles are equipped with electronic ignition (no points) and an on-board computer that automatically adjusts the ignition timing fuel mixture and idle speed. In fact, on modern computer-controlled vehicles, it's usually impossible to adjust these yourself:

If you plan to do your own engine performance maintenance, there are some specialized tools you are going to need. You'll need a round wire gauge to check and set the plug gap, a timing light (if your ignition timing is adjustable), a dwell-tach or just a tach (to set idle speed if it is adjustable). A compression gauge is also handy, though not necessary.

An important element in checking the overall condition of your engine is to check compression. This becomes increasingly more important on high mileage vehicles. Compression gauges are available as screw-in types and hold-in types. The screw-in type is slower to use, but eliminates the possibility of a faulty reading due to escaping pressure. A compression reading will uncover many problems that can cause rough running. Normally, these are not the sort of problems that can be cured by a tune-up. Vacuum gauges are also handy for discovering air leaks, late ignition or valve timing, and a number of other problems. Fig. 32 Proper information is vital, so always have a Chilton Total Car Care manual handy

Fig. 33 Two styles of oil drain pan. The screw-in type on top is more accurate and is easier to use, but is more expensive.

Fig. 34 A variety of tools used for spark plug installation and timing adjustment.


There are two basic kinds of timing lights- DC powered timing lights, which operate from your vehicle's battery, and AC powered timing lights, which operate on 110 volt house current. Of the two, the DC light is preferable because it produces more light to see the timing marks in bright daylight.

Regardless of what kind is used, the light normally connects in series with the No. 1 spark plug using an adapter. Models that are more expensive sometimes use an inductive pickup, which simply clamps around the plug wire and senses firing impulses. Inexpensive models use alligator clips; one clamps onto the connection between the plug and the plug wire, and the others clamp onto the vehicle battery terminals.

Some timing lights will not work on electronic ignition systems, so unless you still own a vehicle equipped with points, check to make sure the timing light you buy will work.

The biggest problem you will probably have when using a timing light is trying to see the timing marks on the crankshaft pulley. Before you time the engine, mark the appropriate timing indicators with fluorescent paint or chalk. Stay out of direct sunlight when you time the engine and buy a timing light with a xenon light, not a neon light. Timing lights that use a xenon tube provide a much brighter flash than those that use a neon tube do. Fig. 35 A modern electronic timing light. Note the inductive pick-up clamp.


You're not going to have much use for the dwell function of a dwell tachometer on late-model vehicles as it is controlled by the computer and is not adjustable. However, if you need to set the base idle speed, and it is adjustable, the tachometer will provide more accuracy than one on your instrument cluster. You don't need one of those gigantic analyzers to set the rpm on your vehicle. Prices range from less than $50$100 and more. Make sure you get a dwell-tach or tach that is compatible with your vehicle's ignition system.

Dwell-tachs are simple to hook up. Some dwell-tachs are powered by the circuit being tested, some operate off the vehicle battery, and some have their own power source. Electronic ignition systems have specific connection procedures and you'll have to check with your dealer to determine the tach hook-up.

There are several Multi-Meter/Engine Analyzers on the market which provide the functions of a Multi Meter and a Engine Analyzers (Dwell & Tach). Fig. 36 Typical aftermarket dwell tachometer- used to check dwell on old point type ignition, and RPM on point and electronic ignition systems.

Electrical and Diagnostic Tools


Never use jumper wires made from a thinner gauge wire than the circuit being tested. If the jumper wire is of too small a gauge, it may overheat and possibly melt. Never use jumpers to bypass high resistance loads in a circuit. Bypassing resistances, in effect, creates a short circuit. This may, in turn, cause damage and fire. Jumper wires should only be used to bypass lengths of wire.

Jumper wires are simple, yet extremely valuable, pieces of test equipment. They are basically test wires which are used to bypass sections of a circuit. Although jumper wires can be purchased, they are usually fabricated from lengths of standard automotive wire and whatever type of connector (alligator clip, spade connector or pin connector) that is required for the particular application being tested. In cramped, hard-to-reach areas, it is advisable to have insulated boots over the jumper wire terminals in order to prevent accidental grounding. It is also advisable to include a standard automotive fuse in any jumper wire. This is commonly referred to as a "fused jumper". By inserting an in-line fuse holder between a set of test leads, a fused jumper wire can be used for bypassing open circuits. Use a 5 amp fuse to provide protection against voltage spikes.

Jumper wires are used primarily to locate open electrical circuits, on either the ground (-) side of the circuit or on the power (+) side. If an electrical component fails to operate, connect the jumper wire between the component and a good ground. If the component operates only with the jumper installed, the ground circuit is open. If the ground circuit is good, but the component does not operate, the circuit between the power feed and component may be open. By moving the jumper wire successively back from the component toward the power source, you can isolate the area of the circuit where the open is located. When the component stops functioning, or the power is cut off, the open is in the segment of wire between the jumper and the point previously tested.

You can sometimes connect the jumper wire directly from the battery to the "hot" terminal of the component, but first make sure the component uses 12 volts in operation. Some electrical components, such as fuel injectors, are designed to operate on about 4 volts, and running 12 volts directly to these components will cause damage.


The test light is used to check circuits and components while electrical current is flowing through them. It is used for voltage and ground tests. To use a 12 volt test light, connect the ground clip to a good ground and probe wherever necessary with the pick. The test light will illuminate when voltage is detected. This does not necessarily mean that 12 volts (or any particular amount of voltage) is present; it only means that some voltage is present. It is advisable before using the test light to touch its ground clip and probe across the battery posts or terminals to make sure the light is operating properly.

Do not use a test light to probe ignition spark plug or coil wires. Never use a pick-type test light to probe wiring on computer controlled systems unless specifically instructed to do so. Any wire insulation that is pierced by the test light probe is a good candidate for failure. Most vehicle manufactures recommend against this, some also recommend against back-probing. Back-probing is where the tip of the probe is forced into the back of the connector. Refer to the specific vehicle manufacturers for recommendations.

Like the jumper wire, the 12 volt test light is used to isolate opens in circuits. But, whereas the jumper wire is used to bypass the open to operate the load, the 12 volt test light is used to locate the presence of voltage in a circuit. If the test light illuminates, there is power up to that point in the circuit; if the test light does not illuminate, there is an open circuit (no power). Move the test light in successive steps back toward the power source until the light in the handle illuminates. The open is then between the probe and a point which was previously probed.
The self-powered test light is similar in design to the 12 volt test light, but contains a battery in the handle. It is most often used in place of a multimeter to check for open or short circuits when power is isolated from the circuit (continuity test).

The battery in a self-powered test light does not provide much current. A weak battery may not provide enough power to illuminate the test light even when a complete circuit is made (especially if there is high resistance in the circuit). Always make sure that the test battery is strong. To check the battery, briefly touch the ground clip to the probe; if the light glows brightly, the battery is strong enough for testing.

A self-powered test light should not be used on any computer controlled system or component. Even the small amount of electricity transmitted by the test light is enough to damage many electronic automotive components. Fig. 37 Test lights are simple to use, however check manufacturers recommendations before probing any wires or connectors.


Multimeters are an extremely useful tool for troubleshooting electrical problems. They can be purchased in either analog or digital form and have a price range to suit any budget. A multimeter is a voltmeter, ammeter and ohmmeter (along with other features) combined into one instrument. It is often used when testing solid state circuits because of its high input impedance (usually 10 megaohms or more). A brief description of the multimeter main test functions follows: Voltmeter- the voltmeter is used to measure voltage at any point in a circuit, or to measure the voltage drop across any part of a circuit. Voltmeters usually have various scales and a selector switch to allow the reading of different voltage ranges. The voltmeter has a positive and a negative lead. To avoid damage to the meter, always connect the negative lead to the negative (-) side of the circuit (to ground or nearest the ground side of the circuit) and connect the positive lead to the positive (+) side of the circuit (to the power source or the nearest power source). Note that the negative voltmeter lead will always be black and that the positive voltmeter will always be some color other than black (usually red). Ohmmeter- the ohmmeter is designed to read resistance (measured in ohms) in a circuit or component. All ohmmeters will have a selector switch which permits the measurement of different ranges of resistance (usually the selector switch allows the multiplication of the meter reading by 10, 100, 1,000 and 10,000). Since the meters are powered by an internal battery, the ohmmeter can be used as a self-powered test light. When the ohmmeter is connected, current from the ohmmeter flows through the circuit or component being tested. Since the ohmmeter's internal resistance and voltage are known values, the amount of current flow through the meter depends on the resistance of the circuit or component being tested.

The ohmmeter can also be used to perform a continuity test for suspected open circuits. In using the meter for making continuity checks, do not be concerned with the actual resistance readings. Zero resistance, or any ohm reading, indicates continuity in the circuit. Infinite resistance indicates an opening in the circuit. A high resistance reading where there should be none indicates a problem in the circuit. Checks for short circuits are made in the same manner as checks for open circuits, except that the circuit must be isolated from both power and normal ground. Infinite resistance indicates no continuity to ground, while zero resistance indicates a dead short to ground.

Never use an ohmmeter to check the resistance of a component or wire while there is voltage applied to the circuit. The voltage could severely damage the meter.

Ammeter- an ammeter measures the amount of current flowing through a circuit in units called amperes or amps. At normal operating voltage, most circuits have a characteristic amount of amperes, called "current draw" which can be measured using an ammeter. By referring to a specified current draw rating, then measuring the amperes and comparing the two values, one can determine what is happening within the circuit to aid in diagnosis. An open circuit, for example, will not allow any current to flow, so the ammeter reading will be zero. A damaged component or circuit will have an increased current draw, so the reading will be high.
The ammeter is always connected in series with the circuit being tested. All of the current that normally flows through the circuit must also flow through the ammeter; if there is any other path for the current to follow, the ammeter reading will not be accurate. The ammeter itself has very little resistance to current flow and, therefore, will not affect the circuit, but it will measure current draw only when the circuit is closed and electricity is flowing. Excessive current draw can blow fuses and drain the battery, while a reduced current draw can cause motors to run slowly, lights to dim and other components to not operate properly. Fig. 38 Combination Multi-Meter and Engine Analyzer makes these the most important diagnostic tools you own. Pro model on right has inductive pick-up


All late-model vehicles utilize computer modules to monitor and control the functions of on-board systems. These modules are known by many names such as Engine Control Unit (ECU), Engine Control Module (ECM), Powertrain Control Module (PCM) and Vehicle Control Module (VCM) just to name a few. When problems occur in control circuits, these modules record a diagnostic trouble code which can be used to help solve the problem. Over the years, there have been many different types of systems, each with their own unique way of retrieving these codes. On a good number of the older systems, the stored codes were flashed on various trouble lights (found in the dashboard) once a small jumper wire was placed across the proper diagnostic terminals. However the use of a hand-held scan tool was still preferred for these systems.

For some models produced during the 1995 model year and on almost every single 1996 and later model, a new form of trouble codes was developed which required the use of a scan tool. On Board Diagnostic-II (OBD-II) compliant vehicles use a 5 digit, alpha-numeric code which would be difficult or impossible to read using a flashing light, therefore trouble code reading on an OBD-II compliant requires a scan tool.

There are many manufacturers of these tools, but a purchaser must be certain that the tool is proper for the intended use. If you own a scan type tool, it probably came with comprehensive instructions on proper use. Be sure to follow the instructions that came with your unit

The scan tool allows any stored codes to be read from the computer module memory. The tool also allows the operator to view the data being sent to the computer control module while the engine is running. This ability has obvious diagnostic advantages; the use of the scan tool is frequently required for component testing. The scan tool makes collecting information easier; the data must be correctly interpreted by an operator familiar with the system.

An example of the usefulness of the scan tool may be seen in the case of a temperature sensor which has changed its electrical characteristics. The computer module is reacting to an apparently warmer engine (causing a driveability problem), but the sensor's voltage has not changed enough to set a fault code. Connecting the scan tool, the voltage signal being sent to the module may be viewed; comparison to normal values or a known good vehicle reveals the problem quickly. Fig. 39 Typical aftermarket scan tool used to access diagnostic codes from the Electronic Control Module.

Fig. 40 This Auto Xray® scan tool uses manufacturer specific cables to interface with the various connectors.


Soldering is a quick, efficient method of joining metals permanently. Everyone who has the occasion to make electrical repairs should know how to solder. Electrical connections that are soldered are far less likely to come apart and will conduct electricity far better than connections that are only "pig-tailed" together.

The most popular (and preferred) method of soldering is with an electric soldering gun. Soldering irons are available in many sizes and wattage ratings. Irons with high wattage ratings deliver higher temperatures and recover lost heat faster. A small soldering iron rated for no more than 40 watts is recommended for home use, especially on electrical projects where excess heat can damage the components being soldered.

There are three ingredients necessary for successful soldering- proper flux, good solder and sufficient heat.


A soldering flux is necessary to clean the metal of tarnish, prepare it for soldering and to enable the solder to spread into tiny crevices. When soldering electrical work, always use a resin flux or resin core solder, which is non-corrosive and will not attract moisture once the job is finished. Other types of flux (acid-core) will leave a residue that will attract moisture, causing the wires to corrode.

Good Solder

Tin is a unique metal with a low melting point. In a molten state, it dissolves and alloys easily with many metals. Solder is made by mixing tin (which is very expensive) with lead (which is very inexpensive). The most common proportions are 40/60, 50/50 and 60/40, the percentage of tin always being listed first. Low-priced solders often contain less tin, making them very difficult for a beginner to use because more heat is required to melt the solder. A common solder is 40/60 which is well suited for all-around general use, but 60/40 melts easier, has more tin for a better joint and is preferred for electrical work.

Sufficient Heat

Successful soldering requires that the metals to be joined be heated to a temperature that will melt the solder, usually somewhere around 360–460°F (182–237°C), depending on the tin content of the solder. Contrary to popular belief, the purpose of the soldering iron is not to melt the solder itself, but to heat the parts being soldered to a temperature high enough to melt solder when it is touched to the work. Melting flux-cored solder on the soldering iron will usually destroy the effectiveness of the flux. Fig. 41 These are several types of soldering tools and guns

How to Solder

  1. Soldering tips are made of copper for good heat conductance, but must be "tinned" regularly for quick transference of heat to the project and to prevent the solder from sticking to the iron. To "tin" the iron, simply heat it and touch flux-cored solder to the tip; the solder will flow over the tip. Wipe the excess off with a rag.
  2. After some use, the tip may become pitted. If so, dress the tip smooth with a fine file and "tin" the tip again.
  3. An old saying holds that "metals well-cleaned are half soldered". Flux-cored solder will remove oxides, but rust, bits of insulation and oil or grease must be removed with a wire brush or emery cloth.
  4. For maximum strength in soldered parts, the joint must start off clean and tight. Weak joints will result in gaps too wide for the solder to bridge.
  5. If a separate soldering flux is used, it should be brushed or swabbed on only those areas that are to be soldered. Most solder contains a core of flux and separate fluxing is unnecessary.
  6. Hold the work to be soldered firmly. It is best to solder on a wooden board, because a metal vise will only rob the piece to be soldered of heat and make it difficult to melt solder. Hold the soldering tip with the broadest face against the work to be soldered. Apply solder under the tip close to the work. Apply enough solder to give a heavy film between the iron and piece being soldered, moving slowly and making sure the solder melts properly. Keep the work level or the solder will run to the lowest part, and favor the thicker parts, because these require more heat to melt the solder. If the soldering tip overheats, (the solder coating on the face of the tip burns up). The tip should be re-tinned.
  7. Once the soldering is completed, let the soldered joint stand until cool.

Fig. 42 If necessary, dress a pitted tip with a fine file

Fig. 43 Tinning the soldering iron

Fig. 44 Wipe the excess solder from the iron while hot

Fig. 45 The correct method of soldering. Let the heat transferred to the work melt the solder