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302 you can pull it o ff the plug The shiny thing sticking out of the e n g in e block is the term inal o f the spark plug Figure 12-10, later in this chapter, shows you all the parts of a spark plug, including the term inal Use a nice soft rag or a sm all paint brush to clean around the area w here the spark plug enters the block - or you can blow the dirt away w ith a soda straw D oing so keeps loose junk from falling down the hole into the cylinder w hen the plug is rem oved Find your spark plug socket (the big one with the rubber lining) and place it dow n over the spark plug; exert some pressure w hile turning it slightly to be sure that it's all the way down Like everything else in auto repair, don’t be afraid to use som e strength But it in an even, controlled manner If you bang or je rk things, you can dam age them , but you’ll never get anyw here if you tippy-toe around Pick up your ratchet handle and stick the square end into the square hole in the spark-plug socket I f you can w ork m ore com fortably by adding a couple of extensions betw een the handle and the socket so that you can move the handle freely from side to side without hit ting anything, go ahead You add them in the same way you added the socket to the handle (If you have trouble with gpttinp the plug loose, see the “ D ealing with difficult plugs” section, w hich follow s, for encouragem ent.) The little knob on the back o f the ratchet handle makes the ratchet turn the socket either clockw ise or counter clockw ise) You can tell w hich way the handle will turn the plug by listening to the clicks that the handle m akes when you m ove it in one direction If it clicks w hen you move it to the right, it will turn the socket counterclockw ise when you m ove it, silen tly, to the left If the clicks are audible on 303 the leftward swing, it will move the socket clockwise on the rightward swing Every screw, nut, bolt, and so on that you encounter should loosen counterclockwise and tighten clockwise If your ratchet clicks in the wrong direction, just move that little knob to reverse the direction Figure 12-9 shows you the proper way to use a socket wrench, and the sidebar “Breaking loose old plugs and m isconceptions” tells you how to handle difficult plugs Loosen the spark plug by turning it counterclockwise When the ratchet turns freely, finish the job by rem oving the ratchet handle and turning the socket by hand until the plug is free from the engine After you’ve rem oved the spark plug from the engine, re move the plug from the socket But don’t go on to the next plug until you’ve read the plug (see the section “Reading your spark plugs” and Table 12-1) and gapped and replaced it, follow ing the instructions later in this chapter Dealing with difficult plugs W ith all the stuff crammed under the hoods o f vehicles, it can be hard to get at some spark plugs and, even when you can reach 304 them easily, they may be difficult to remove This section provides tips on extracting your spark plugs with a minimum o f hassle A lm ost every vehicle has at least one plug that’s a miser able th in g to reach If you have one, save it for last Then you can work on it with the satisfaction o f know ing that, when you get the darn thing finished, you will have finished the job If you find that one or more plugs are blocked by an air conditioner or som e other part, try using various ratchet handle extensions to get around the problem There are universal ex tensions that allow the ratchet handle to be held at odd angles; T-bar handles for better leverage; and offset handles for hardto-reach places (See C hapter for exam ples.) On som e vehicles, you can’t get at the plugs until you re move other parts that are in the way On som e transverse en gines, you have to rem ove the top engine m ount bolts by the radiator so that you can tilt the engine forw ard to replace the rear spark plugs And on other engines, it m ay be easier to get to som e spark plugs from underneath or through the wheel well area On som e sm all cars equipped with optional big engines, you have to hoist the entire engine out o f the car to reach at least one plug I f you have one o f these beasts, I bet that when you finally get that plug out, you’ll find that it’s never been replaced during all the professional tune-ups you’ve paid for And you’ve paid even m ore because that one funky plug probably not only increased your fuel consum ption but also added to air pollution Both you and your car should be glad to get rid o f it! I f you absolutely cannot reach the offending plug, you can always drive to your service station and hum bly ask them to change just that one plug T hey w on’t like it, but it is a last resort If you get to that point, you’ll probably be glad to pay to have it done But try very hard first I f you ca n ’t get to the plug in the ordinary way, go under, over, around, or through 305 gaps in the thing that’s blocking it Or get someone to help you move w hat’s in the way (but be sure that you can get it back in place correctly) Use your imagination; it’s the only hard part of the job And you won’t have to it again for a long time If you’re lucky enough to own a car without air conditioning, power steering, power brakes, and so on, chances are much greater that all your plugs will be easy to get at Think it over next time you’re tempted to buy a vehicle with all the “extras.” Those “extras” tend to block the things you want to work on, and they often go wrong them selves Some, like air condition ing if you live in a hot climate, are worth it Others, like power brakes on a small car, are not Reading your spark plugs You can actually read your spark plugs for valuable “clues” about how your engine is operating To read your spark plugs, follow these steps: When the first spark plug is out o f the engine, rem ove the plug from the spark plug socket and take a look at it Compare the deposits on the plug to the conditions shown in Table 12-1 Figure 12-10 can help you to identify the various parts o f a plug m entioned in the table Check the plug’s shell, insulator, and gaskets for signs of cracking or chipping Look at the plug’s firing end (the end o f your plug that was inside the cylinder) The hook at the top is the side electrode (refer to Figure 12-10) The bump right under its tip is called the cen ter electrode The spark comes up the center o f the plug and jum ps the gap between these two electrodes This gap must be a particular distance across for your engine to run effi ciently What Your Old Spark Plugs Tell You about Your Car Table 12-1 Condition N o rm a l p lu g Clues Probable Causes Remedies B r o w n o r g r a y is h - ta n E v e ry th in g 's fin e J u s t c le a n a n d re g a p th e p lu g B la c k , d ry , f lu f f y s o o t o n O v e rly r ic h f u e l/ a ir m ix tu r e ; S w it c h to " h o t t e r " p lu g s in s u la to r tip a n d e le c tr o d e s m a lfu n c tio n in g c h o k e ; d ir t y a ir (T h e h ig h e r th e p lu g filte r ; o r ju s t to o m u c h d r iv in g a t n u m b e r, th e h o tte r th e p lu g ) d e p o s it o n s id e e le c tr o d e C a rb o n -fo u le d p lu g lo w s p e e d s , o r s ta n d in g a n d O tl-fo u le d p lu g B u r n t p lu g W e t, b la c k , o ily d e p o s its O il m a y b e le a k in g in to c y lin - C le a n a n d re g a p th e p lu g o n in s u la to r tip a n d e le c tr o d e s d e r s p a s t w o r n p is to n s o r p o o r ly o r r e p la c e it, b u t fin d o u t a d ju s te d o r w o r n v a lv e s w h e r e th e le a k is c o m in g fro m R e p la c e th e p lu g B lis te r s o n in s u la to r tip , E n g in e o v e r h e a tin g ; g a p to o m e lte d e le c tr o d e s , w id e ; w r o n g o r lo o s e p lu g s ; b u r n t s tu ff o v e r ly le a n f u e l/ a ir m ix tu r e ; in c o r r e c t tim in g W o r n p lu g S e v e re ly e r o d e d o r w o r n e le c tr o d e s P lu g h a s b e e n in th e r e to o lo n g R e p la c e th e p lu g 306 id lin g fo r a lo n g tim e 307 T e rm in a l In s u la to r R e s is to r - S p r in g S h e ll - C e n te r seal G asket Figure 12-10: C e n te r The e le c tr o d e anatom y of a spark plug -T h re a d s ^Gap In s u la to r tip - S ide e le c tr o d e Take your wire or taper feeler gauge and locate the proper wire (if your spark-plug gap specifications say 035, look for this number near one o f the wires on the gauge) Then slip that gauge wire between the two electrodes on your old plug Figure 12-11 shows why you should never use a flat feeler gauge for this purpose The reading will be inaccurate Figure 12-11: W hy you can't use a fla t fe e le r gauge on an old spark plug 308 The gauge wire probably has a lot o f room to wiggle around in This may be because your old plug has worn down its center electrode, causing a gap that is too large If the gauge goes in and out with a lot o f room on either side, the gap is too large If the gauge can’t fit between the center and side electrodes, the gap is too sm all, which means that the spark plug is not burning the fuel/air mixture efficiently Look at the little center electrode bump again and use Table 12-1 to judge its condition Is it nice and cylindrical, like the center electrodes on your new spark plugs? Has the electrod e’s flat top worn down to a rounded lump? Or has it worn down on only one side? C hances are it’s pretty w orn because it’s old When the center electrode wears down, the gap becom es too large W hen you your tune-ups yourself, you’ll probably check your plugs m ore often and replace them before they get too worn to operate efficiently Clean the plug Then either gap it or replace it with a new one, follow ing the instructions in the next two sections To clean a plug, gently scrub the gunk and goo away with a wire brush Keep in m ind that although you don’t need to clean new spark plugs, you need to gap them Some plugs are sold “ pregapped,” but I’d check them w ith a feeler gauge any way R epeat the entire process for each additional plug, work ing on only one at a time A good w ay to keep track o f w h ich plug belongs in which cylin der is to use an egg carton as a container and put the plugs into the carton’s d epressions in numerical order as you rem ove them from the engine E ither replace all the plugs with new ones or clean and reinstall all the old ones Don’t m ix plugs in varying states of wear If you do, your engine w on’t operate efficien tly If you find 309 that a few o f your old plugs aren’t too worn and are in fairly good shape, but you need to replace the others, clean and regap the salvageable plugs and store them in your trunk com part ment tool kit for em ergencies Som etim es you can cure a problem - such as carbon-fouled plugs - by going to a hotter- or cooler-burning plug You can identify these by the plug number The higher the number, the hotter the plug Never go more than one step hotter or cooler at a time If your plugs indicate that som ething is seriously wrong with the way your engine is running, ask a professional m e chanic for an opinion If you’re told that it requires extensive or expensive work, get a second opinion at another service facility without telling the technicians that you went to the first place This is a good policy to follow whenever major repair work is suggested We wisely get second opinions when doctors tell us we need major surgery; why not give your vehicle the same thorough attention before incurring a major expense? Gapping your spark plugs As I m entioned in the preceding section, the space, or gap, between the center and side electrodes needs to be a particular distance across; otherw ise, your plugs don’t fire efficiently A d justing the distance between the two electrodes is called g a p ping your spark plugs Gap new as well as old spark plugs, even if the package says that the new plugs are “pre-gapped.” To avoid problem s, work on only one plug at a time, in cylinder sequence order The follow ing steps explain how to gap your spark plugs: If you're regapping a used plug, make sure that it's clean If you’re using a new plug, it should be clean and newlooking, with the tip o f the side electrode centered over the center electrode There should be no cracks or bubbles in the porcelain insu lator, and the threads should be unbroken 310 Take your feeler gauge, select the proper wire, and run it betw een the electrodes (see Figure 12-12) If the wire doesn’t go through or if it goes through too easily, without touching the electrodes, you need to adjust the distance betw een the electrodes Adjust the gap as necessary I f the wire didn’t go through, the gap is too narrow Hook the part o f the feeler gauge that is used for bending elec trodes under the side electrode and tug very gen tly to widen the gap I f the wire goes through too easily, without touching the electrodes, the gap is wide Press the side electrode against a clean, m a r-proof surface, very gently, until it’s slightly bent down toward the cen ter electrode Run the gauge through the gap again R epeat Steps and until the gap is ju s t right You want the gauge w ire to go through fairly easily, just catching the electrodes as it passes The wire should just “hang” in the gap but go through with a little guidance I f you keep getting the gap too narrow or too wide, don't feel bad Everyone I know goes through the “too large-too small-too 311 large” bit a couple o f times for each plug, especially the perfec tionists After you’re done gapping your spark plug, it’s time to in sert it in the engine The next section has the details Installing a spark plug To insert a spark plug into the engine, follow these steps: Clean the spark plug hole in the cylinder block with a clean, lint-free cloth Wipe away from the hole; don’t shove any dirt into it Lightly coat the threads o f the spark plug with anti-seize compound, being careful not to get any on the center or side electrodes Carefully begin threading the spark plug into the engine by hand, turning it clockwise This is called “seating the plug.” You have to it by hand, or you run the risk o f starting the plug crooked and ruining the threads on the plug or threads in the engine If you have trouble holding onto the plug, you can buy a spark plug starter and fit it over the plug, or you can use an old spark plug wire boot or a piece o f vacuum hose to make your own After you engage the plug by hand, turn it at least two full turns before utilizing the spark plug socket and ratchet Slip the spark plug socket over the spark plug, attach the ratchet handle, and continue turning the plug clockwise until you m eet resistance Don’t overtighten the plug (you can crack the porcelain); just get it in nice and tight with no wiggle The plug should stick a little when you try to loosen it, but you should be able to loosen it again without straining yourself Tighten and loosen the first plug once or twice to get the proper feel o f the thing 587 DOT identification and registration The DOT identification number on the sidewall serves as a registration number for the tire in case o f a recall This number tells where and when the tire was manufactured Most of the data in the code isn’t important for your purposes, but if you’re curious, the following example tells what the various letters and numbers o f a sample DOT-code, DOT WOKAABC 262, mean: ♦ DOT indicates that the tire meets or exceeds U.S De partment o f Transportation safety standards ♦ WO identifies the plant where the tire was made Be cause tires are made at many different plants, you don’t need to know all the variations of this code If it matters to you where your tires were made, ask the dealer ♦ KA indicates the tire size (In this case, the tire size is P194/75R14 Because the tire size is also on the sidewall, you don’t need to know all the variations of this code, either.) ♦ ABC identifies the brand or characteristics o f the tire Instead o f decoding this piece, read the brochure that describes the tire in detail ♦ joo 262 indicates when the tire was made (In this case, the number 262 means that the tire was made during the 26th week o f 1982 Nifty, huh?) When you buy new tires, make sure that th ey’re properly registered Under federal law, the dealer is required to put the tire’s DOT number and the dealer’s name and address on a form that is then sent to the manufacturer Although tire outlets owned by manufacturers and certain brand-name out lets must send them in, independent tire dealers can simply fill out the forms and give them to customers to mail to the manufacturer Unlike guarantees and warrantees, in case o f a recall, you aren t eligible to receive replacem ents unless your 588 tires have been properly registered and you respond to the recall within 60 days For m ore ideas about buying tires, see “Tips for Buying Tires,” later in this chapter Other sidewall information Check the sidewalls for the following safety data, too: ♦ M A X L O A D : H ow much weight the tire can bear safely, usually expressed in kilograms (kg) and pounds (lbs) ♦ M A X P R E S S : The maximum air pressure the tire can safely hold, usually expressed in pounds per square inch (psi) M A X P R E S S is not the pressure to m a intain in your tires; you can find the manufacturer’s recom m ended pres sure for the best handling and wear on the tire decal found on the door, door pillar, console, glove box, or trunk o f your vehicle You can find instructions for checking tire pressure, read ing treads for clues, and other work that you can on your tires in the “Caring for Your T ires” section, later in this chap ter Tips for Buying Tires Before you rush out and buy a set o f tires, you have a couple o f other things to consider Tire wear is affected by a number o f factors besides construction: the condition of the vehicle’s brake system and suspension system; inflation and alignm ent; driv in g and braking techniques; d rivin g at high speeds, w h ich raises tire temperatures and causes them to wear prem aturely; how great a load you carry; road condi tions; and climate Here are som e o f the types o f tires that you m ay want to consider: 589 ♦ Basic all-season tires are standard equipment on most cars The speed rating (see the “Speed rating” section earlier in the chapter) is usually S T If “M +S” (mud and snow) is printed on the sidew all, the tire will perform well in inclement weather without the need for snow tires ♦ Touring tires are generally more expensive than basic all-season tires W hether they’re worth the money de pends on the individual product These tires usually are speed-rated S or T ♦ Perform ance tires are designed for people who drive “aggressively” They perform better in terms of braking and cornering but are usually noisier and wear out more quickly They are usually speed-rated H and have a wide, squatty profile ♦ Ultra-high perform ance tires have both the positive and the negative aspects of performance tires to a greater degree: They go faster, brake and handle better in wet and dry conditions, but ride less comfortably and Wear out even faster They are even wider and are usually speedrated V or Z ♦ Light-truck tires are intended for use on light trucks and SUVs They come in a variety o f styles designed for normal conditions, driving on- or off-road, or both The thicker treads on the off-road variety offer better trac tion on unpaved surfaces Light-truck tires also vary for carrying normal, heavy, and extra-heavy loads ♦ Snow tires may be better than all-season tires for driv ing in mountainous areas with heavy snowfall, but they’re noisy and don’t handle as well on dry roads, so use them only when necessary ♦ “R un -flat” tires can be driven on without any air pres sure inside the tire Run-flat equipped vehicles may not even come with a jack or spare tire (If you’re driving a 590 1997 or newer Chevrolet Corvette or a sim ilarly equipped new vehicle, you probably have this special type of radial tire.) The sidewalls have specially com pounded inserts that prevent the tire from caving in w h en the tire loses air pressure You can drive some run-flat tires up to 50 mph for 50 miles or more without further damaging the tire Running on a run-flat at high speeds for a long period can dam age them , so car m anufacturers incorporate a w arning system For example, the C orvette has tire pres sure sensors at each w heel so that the driver can be w a rn ed when one or m ore tires are flat Because the driver can’t feel any difference when a run-flat goes flat, a warning light illuminates on the instrum ent panel, sig naling the driver to limit his or her driving speed and distance to avoid further damage to the tire or wheel Before making a decision about a particular type of tire, take a close look at your driving habits: A re you h ard on tire s? I f you tend to “ burn rubber” when cornering, starting, and stopping, you know where that rubber comes from A pair o f cheaply made tires will wear out quickly, so buy the best quality you can afford Do you drive a great deal and m ost o f your driv ing on h igh -sp eed free w a y s? A tire with a harder surface will take longer to wear out under these conditions Do you drive a lot on u n p aved ro ck y roads, carry h ea v y load s, or leave you r car in the hot sun for long h o u rs? Y ou’ll need higher-quality tires that have the stamina to endure these challenges W h a t’s the w ea th er like in your a re a ? Today, frontw heel drive vehicles w'ith high-tech all-season tires get better traction than the old snow tires, which you had to replace when warm weather set in However, if you drive under ex trem e conditions, you may want to check out tires designed 591 for them: I f it rains a lot, look for rain tires with super-wide grooves in the treads For places with lots o f snow or icy hills, look for “M +S” (mud and snow) on the sidewall Do you drive m ostly in local stop-and-go traffic, with many tu rn s? Softer tires with wider treads will suit you best How long you intend to keep your car? Putting a pair of expensive tires on a vehicle that you intend to get rid of in 10,000 or 20,000 miles is foolish Oh, it’s possible to put well over 100,000 miles on a vehicle - especially if you main tain it properly - but if you have a relatively old vehicle with many miles on it already, and you don’t intend to keep it very long, I wouldn’t buy a pair o f expensive mega-mile tires for it Your car may surprise you and outlive its tires, but chances are that it w on’t Similarly, it’s foolish to put high-perfor mance tires on a vehicle that will be driven mostly at normal speeds in city and highw'ay traffic On the other hand, if you intend to keep your vehicle for a few years, you’ll save m oney in the long run by opting for more expensive, longer-lasting tires than “cheapos” or tires rated for less than 40,000 miles Cheap tires wear out more quickly and cost more in the long run if you figure in the cost of buying, mounting, and balancing that second set W hat’s more, if you suffer a blowout or your tires fail to grip the road, you’ll pay a great deal more if your vehicle - or you - is in jured If you drive only a couple o f thousand miles a year, don’t expect a pair of 40,000-m ile radials to last forever Rubber treads tend to rot eventually because o f the ozone in the air, which causes cracks and hard spots in the sidewalls - a condi tion called ozone checking For this reason, if you’ve used your tires for more than 40,000 miles, even if the treads are in good shape, have the tires checked to make sure that deterio rating rubber hasn’t made them prone to blowouts and leaks In addition to knowing which kind of tire is best for your 592 car and understanding the tire codes (explained in the sec tion called “The Secrets on Your Sidewalls, Revealed!” ), keep the following tips in mind when you shop for tires: ♦ You can find the p roper tire size for your car in the ow n er’s m anual or on a sticker affixed to the vehicle If neither exists, ask your dealer ♦ Although you should never buy tires that are smaller than those specified for your vehicle, you can buy tires a size or two larger (if the car’s wheel clearance allows it) for better handling or loa d -carrying ability However, you should buy these larger tires in pairs and place them on the same axle Ask your m echanic or a reputable tire or auto dealer for advice about the proper size range for your vehicle For more advice, see “Tips for Buying Tires,” later in this chapter ♦ Never use two different-sized tires on the same axle ♦ ri If you’re replacing just one or two tires, put the new ones on the front for better cornering control and brak ing (because weight transfers to the front tires w’hen you brake) ♦ I f you still have bias-ply or bias-belted tires on your car, you must replace all o f them at the same time with radi als when they wear out You can’t mix different kinds of tires on the same vehicle; you should have the same type on all four wheels The ride is so different that radial tires would throw your car out o f alignment if you tried them in com bination with the old-style tires ♦ Remem ber that you have to “break in ” new’ tires, so don’t drive faster than 60 mph for the first 50 miles on a new tire or spare ♦ Store tires that you aren’t using in the dark, away from extreme heat and electric motors that create ozone 593 Caring for your Tires Tires don’t require a great deal of maintenance, but the jobs in this section will pay off handsomely by increasing your tires’ longevity, handling, and performance, as well as provid ing you with a more comfortable ride Checking tire inflation pressure The single most important factor in caring for your tires is maintaining the correct inflation pressure You should check your tires at least once a month and before every long trip to see that they’re properly inflated Underinflated tires wear out faster, create excessive heat, increase fuel consumption, and make the vehicle harder to handle Overinflated tires can blow out more easily, wear out faster, and make the vehicle unstable and unsafe to handle The section “Checking your tires for wear,” later in this chapter, can help you check for signs o f these problems and tells you what to about them Check tire pressure in the morning before you use the car or when you’ve driven it less than a mile If you drive more than that, your tires will heat up and the air will expand, so you won’t get an accurate reading In hot weather, the pressure in your tires rises as the air in them heats up and expands, which can result in overinflation Conversely, in cold weather, the pressure falls as the cold air contracts and your tires can end up underinflated As you’ll see in the section called “Checking your tires for wear,” these conditions can cause your tires to wear unevenly and wear out prematurely If the weather gets very cold, it looks as though it will stay that way for some time, and you get a low reading, you may want to add a bit o f air to your tires to bring the pressure back up Generally, though, tires that are correctly inflated tend to wear properly in spite o f minor weather ups and dowms Just check them regularly to keep things under control, and try not to check them under extreme temperature conditions 594 or after you’ve been driving around Here’s what you need to to check the air pressure in your tires: Buy an a ccu te tire gauge at a h ardw are store or auto su p p ly store Figure 19-2 shows you what a tire gauge looks like show you how to use one a little later in this section D eterm in e the p rop er air p ressu re for your tires by look in g for the p rop er in flation pressure on the tire d eca l You can find the tire decal on one o f the doors, door pillars, glove box, console, or trunk Som etim es the tire decal sp ecifie s one pressure for the front tires and a different pressure for the rear tires Don’t consult the tire’s sidewall for the proper infla tion pressure The sidewall lists the maximum pres sure that the tire is capable o f handling, not the pres sure that’s best for performance and wear (unless you’re carrying heavy loads) R em ove the little cap from the tire valve that sticks out o f yo u r tire n ear the w h eel rim You don’t have to remove your hub cap to so Place the o p en , rou n d ed end o f the tire gauge against the valve so that the little pin in the gauge contacts th e pin in the valve (see Figure 19-2) Press the ga u g e against the valve stem You'll hear a hissing sound as air starts to escape from the tire A t this point, you’ll also see a little stick emerge from the other end o f the tire gauge It emerges partway alm ost as soon as the air starts to hiss and stops em erg in g almost immediately W ith ou t p u sh in g the stick back in, rem o v e the gauge from the tire valve 595 Figure 19-2: Use a tire gauge to see w h e th e r your tires are properly inflated Look at the stick w ithout touching it There are little num bers on it; pay attention to the last num ber show ing The last number is the amount o f air pressure in your tire, as shown in Figure 19-2 Does the gauge indicate the proper amount of pressure recommended on the decal? Add air if necessary If the pressure seems too low, press the gauge against the valve stem again If it still doesn’t move, you need more air Follow the steps in “Adding air to your tires.” R epeat these steps for each tire - and don’t for get the sp are! Adding air to your tires If your tires appear to be low, note the amount that they’re underinflated, drive to a local gas station, and follow these steps: Park you r vehicle so that you can reach all four tires with the air hose R em ove the cap from the tire valve on the first tire U se y o u r tire gauge to ch eck the air pressure in the tire and see how m uch it’s ch an ged so that you can add the sam e am ou nt o f air that the tire la ck e d before you drove it to the station The pressure will have increased because driving causes the tires to heat up and the air inside them to expand U se the air hose to add air in sh ort b u rsts, check in g the pressu re each tim e w ith yo u r tire gauge The gauges on many station air hoses are inaccurate; that’s why you should use your own gauge to ensure proper inflation If yo u add too m uch air, let som e out by pressing the pin on the tire valve w ith the b ack of the air h ose n ozzle or with the little knob on the back of the ro u n d e d end o f the tire gauge K e e p ch ec k in g until you get the p ressu re right D o n ’t get discouraged if you have to keep adjusting the air pressure No one hits it on the head the first tim e! Rotating your tires People have differing points o f view on tire rotation Some say that you can get up to 20 percent more wear if you rotate your tires Others caution against rotating them because rota tion may hide the distinctive tread-w ear patterns that pro vide the clues to poor align m en t, w orn sh o ck absorbers, and defective b k e s found in the “C hecking your tires for w ear” section, later in this chapter I f your tires seem to be wearing evenly and you haven’t had any o f these problems, then it’s a good idea to rotate them - but check them first for signs o f prob lem s that may have arisen since the last time they were rotated For uniform tire wear, the tires on most vehicles should be rotated approxim ately every 6,000 miles, unless they show 597 the signs o f irregular wear in Table 19-1 and Figure 19-8, later in this chapter There are a few other exceptions to this rule: Vehicles that have larger wheels and tires in the rear and vehicles that have different wheels front to back can’t participate in tire rotation And if you have unidirectional tires or tires with asymmetric tread designs, you can’t rotate them in the patterns shown in Figure 19-3 When you rotate tires, you simply move each tire from one wheel to another; for example, one configuration is to move the rear tires forward and the forward tires to the op posite rear locations (see Figure 19-3) However, where you move the tires depends on the type of tires and vehicle you have To find out where to move the tires on your vehicle, consult your owner’s manual (usually, you’ll see a diagram show ing how the tires should be moved), call the tire manufac turer, or ask the dealership O f course, you can always take your vehicle to a service facility and have them rotate the tires for you F r o n t-w h e e l d riv e Figure 19-3: H o w to r o ta te y o u r t ir e s R e a r-w h e e l d riv e 598 Many shops include free tire rotation and w h eel balanc ing in oil-change and other special service promotions, and m ost tire dealers include p e riod ic tire rotation and wheel balancing in their warranties (I explain what wheel balancing is in the next section.) The tires on the front and rear wheels may require differ ent air pressures After the tires are rotated, remember to adjust the air pressure on each tire to whatever is indicated on the tire decal on your vehicle or in your ow ner’s manual I f you have a matching, full-sized spare, you can include it in the rotation process by starting it out in the right rear position and using the tire that would have been moved to the right rear as the spare tire until the next rotation Do not include a “Tem porary Use O nly” spare tire (those teeny little ones) in any rotation pattern (But you knew' that, right?) Balancing your wheels W h eel b alan cin g does a lot to eliminate some of the prin cipal causes o f tire wrear And an unbalanced wheel and tire can create an annoying vibration on smooth roads Because balancing is a job that should be done w'ith the proper equip ment, and because that equipment is costly, while balancing is generally cheap, go to a service facility or tire store and have th^m the jo b for you Just rem em ber that there are two kinds o f wheel balancing: static and dynam ic ♦ S ta tic b a lla n c in g deals with the even distribution of w eigh t around the axle You can tell that you need to have your wheels statically balanced if a wheel (or more than one w'heel) tends to rotate by itself when the car is ja ck e d up It rotates because one part o f the wheel is heavier than the rest To correct this problem, a techni cian finds the heavy spot and applies tire weights to the opposite side o f the heavy spot to balance it out ♦ D yn am ic b alancin g deals with the even distribution of weight along the sp in dle W heels that aren't balanced 599 dynamically tend to wobble and wear more quickly Be cause imbalance can be detected only when the tire is rotated and centrifugal force can act, correcting dynamic balance is a relatively complex procedure Some service stations have computerized balancers that not only bal ance the wheels but also locate the places where the weights are needed and decide how much weight to add Having your tires balanced both statically and dynam i cally shouldn’t cost more than a few dollars If you plan to have your wheels balanced professionally, rotating your tires yourself beforehand is a waste o f time The technicians have to remove the tires to balance them anyway, so they may as well rotate them, too Aligning your wheels A cheap and easy way to substantially improve your ve hicles handling and extend the life o f your tires is to be alert to signs o f m isalignm ent and to have your wheels aligned immediately if the signs appear This job is sometimes called front-end alignm ent because the front wheels get out o f line most often They get that way because o f hard driving with dramatic getaway starts and screeching stops, hitting curbs hard when parking or cornering, accidents, heavy loads, fre quent driving over unpaved roads or into potholes, and nor mal wear and tear as the car gets older Occasionally, the rear wheels need realignment as well Vehicles with indepen dent rear suspensions and front-wheel drive vehicles require four-wheel alignment I used to think that alignment involved taking a car that had been bashed out o f shape and literally pulling it back into line Untrue All the technicians is adjust your wheels to make sure that they track in a nice, straight line w’hen you drive To so, they use special equipment to check the fol lowing points: ♦ C aster has to with the position of your steering knuckle 600 as compared to a vertical line when viewed from the side (see Figure 19-4) I f properly adjusted, it m akes your wheels track in a straight line instead o f weaving or shimm ying at high speeds Caster also helps return the steering w h eel to a straight-ahead position after com pleting a turn Caster angle Centerline Vertical ♦ st®erin9 knuckle C am ber is the inward or outward tilt o f the top of the wheels when view ed from the front/rear o f the car - how “bow-legged” or “kn ockk n eed ” they are (see Figure 19-5) I f the w heels d on ’t hang properly, your tires wear out more quickly, and your car is harder to handle 601 Toe involves placing your tires so that they are prop erly positioned par allel to the frame when driving down the road Some cars call for a little toe-in (tires pointing inward- see Figure 19-6), while otheis are set with a little toe-out (tires pointing outward) The result should be a nice, straight track w-hen the car is moving quickly On some front wheel drive cars, the manufacturer may set the rear tires with a little toe-in and the front tires with a little toe-out so that the tires are parallel to the frame when the vehicle is in motion Distance at rear » Figure 19-6: Toe-in ♦ Front Distance at fro n t Turning radius is the relation o f one front wheel to the other on turns If you turn to the right, the right front tire needs to turn at a slightly greater angle than the left front tire Your car’s steering arms accom m odate this feat (See Figure 19-7.) If your tires “squeal” sharply on turns, one o f your car’s steering arms may be your prob lem How you know if your wheels need aligning? Look at your tires to see whether they show any o f the tread-wear patterns that I discuss in “Checking your tires for wear,” and pay attention to how your car steers and handles Does it pull to one side? Does the steering feel loose and sloppy? Is your [...]... them in place touch them ? Or is there som ething in betw een? Figures 12- 21, 12- 22, 12- 23, and 12- 24 show how to disconnect several types o f primary term inal arrangem ents Figure 12- 21: On some distribu to rs, the w ire s m ust be loosened from the prim ary te r minal, as shown, before you can remove them 321 Figure 12- 22: On another type of dis tributor, you m ust use a special tool to remove... and you have to rem ove them , clip and all Figures 12- 25, 12- 26, and 12- 27 show a few o f the m ost com m on setups 323 Figure 12- 25: This type of condenser has one s cre w to remove and tw o locating bumps to help you position the new one securely Figure 12- 26: Other con densers have a 'lo c a tin g hole in the mounting bracket 324 Figure 12- 27: Some condensers are c o n nected to the prim ary... tributor, you m ust use a special tool to remove the prim ary term inal nut and release the contact spring and lead wires Figure 12- 23: On other dis tribu to rs, the nut on the prim ary te r m inal must be loosened to release the co n ta ct spring and lead w ire s 322 Figure 12- 24: Still an othe r d is trib u to r has its w ire s attach ed as show n You rem ove the se by loosening the nut at the prim... f driving, and if these look bad, too, ask your m echanic for an opinion Actual point opening 025 F igu re 12- 29: W h y yo u c a n 't g e t an a c c u ra te gap re a d in g on old -. 020 Feeler gauge p o in ts 2 R em ove the old points by rem oving the screw or screws that hold them in place (see Figure 12- 30) I f you have slotted points, sim ply loosen the screw and slide the points out This is a good... distributor cap Look at Figures 12- 37, 12- 38, and 12- 39 to determine which one your vehicle has and then follow the appropriate set o f steps: If you have an adjusting screw, see Figure 12- 37 and follow these steps: 1 Loosen the screw or screws that hold the points in place 2 Turn the off-center adjusting screw 3 Place the correct feeler gauge blade between the point con tacts 3 32 The contacts should still... parts store and start over (You may not collect $20 0, but at least you w on’t go to ja il.) 315 Figure 12- 13: R em oving a d is trib u to r ca p w ith s c re w clam p s Figure 12- 14: R em oving a d is trib u to r cap w ith clip s P o in t se t h o ld -d o w n s c re w Lead w ire s P o in ts co n ta c ts P rim a ry te rm in a l Points C o n d e nse r Figure 12- 15: The a na tom y Coil w ire of a non te... rem ove (Figure 12- 16 shows different kinds o f rotors) Figure 12- 16: V arious typ e s of rotors 317 To rem ove your rotor, follow these steps: 1 Before you remove your rotor, move it on its shaft Does it move easily? If not, you really need this tune-up badly! 2 Remove the rotor from the shaft To remove a small rotor, just lift it straight up o ff the distributor shaft (see Figure 12- 17) To remove... something called the cen trifu ga l advance (see Figure 12- 19) Its function is rather com plicated, it has nothing to do with this m inor tune-up, and it hardly ever breaks Just leave it w here it is and forget it Figure 12- 19: A cen trifu ga l advance 319 R em ove the static shield On som e vehicles, you may find a static shield, shown in Figure 12- 20, which you have to remove before you can change your... wheel lobes slide easily past the points figu re 12- 31: Place only a sm all am ount of lu b ric a n t on the cam w h ee l, or it w ill fly around and burn the points 2 Look at the top o f the distributor shaft, where the rotor was sitting If th ere’s a wick inside it, place a few drops of light engine oil on the wick in the shaft, as shown in Fig ure 12- 32 I f you don’t have the proper kind o f oil, forget... that the clips on both wires touch each other.but do not touch any other metal They’re designed to go back to back so they fit snugly into the clip on the prim ary term inal Refer to Figures 12- 21 through 12- 24 to see the different types o f configurations and the way to reassem ble yours If you don’t see your configuration in these illustrations and you neglected to make a drawing o f the way yours