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Shams + Scams | Glossary
Brakes are one of the most frequently performed repair jobs in the industry, and they are also one of the most expensive. Most people are stunned into catatonia when they are confronted with the cost of a “standard brake job,” which normally runs into the hundreds of dollars. This area of repair is also one of the most profitable for a repair shop, and because of the related safety factors and numerous parts to a complete brake job, it’s prone to plenty of shams and scams.
THE STANDARD BRAKE JOB
In many cases a standard brake job just isn’t standard anymore. You are getting less for that advertised special and paying more for unnecessary parts and services. The primary reason is that brake jobs represent a tremendous bonus ticket (to the shops that sponsor bonuses) for the mechanic. Brake work is performed more often than exhaust and front end work, and it's only overshadowed by tune-ups and other fast repair. Without question, brake service represents the largest repair ticket in any shop short of major engine work.
The term “safety” rings loud and clear with brake service and every mechanic and service manager knows this too well. Bad brakes on your vehicle immediately conjure up images of accidents, collisions, law suits, injuries and other unpleasantries. A vehicle owner is likely to put off other areas of car repair but when it comes to his/her brakes, most people don’t mess around. And in a sense that owner is absolutely right—correct in the assumption that good brakes are imperative. But this well known analogy can be taken too far.
Eventually, you will be faced with the realization that you need a standard two- or four-wheel brake job. It can be a disc/drum combination brake job, a four-wheel drum, or a four-wheel disc brake job. It can be a brake job for one axle only, one set, either a front or rear wheel brake job. The important thing is for you to find a facility that can do the job correctly for your vehicle at the best price.
Before I venture into the standard brake inspection let’s first examine what you can do to find out if your brakes need to be repaired— before you go marching into a brake shop or authorize a sudden repair because of a flash inspection.
Pedal Height—A good determiner is a low brake pedal. Extreme wear of the brake linings would give the brake pedal a lower than normal “feel.” With a non-power braking system a noticeably low brake pedal would be more obvious since this pedal would normally ride a bit higher. By low brake pedal I mean a pedal that's to the floor or nearly there. A distance of about 1/2-inch from the floor, when firmly applied, would be cause for alarm. A low brake pedal could denote thin brake lining, adjustment, a low master fluid level, worn drums or rotors, a leak in the brake lines or wheel cylinders, a lack of fluid in the system, bent foot brake linkage, or a combination of any of the above. If the pedal is low, check your master cylinder (located in the engine compartment, usually on the firewall on the driver’s side) to make sure the fluid level is up. The problem could be remedied by adding a few ounces of brake fluid, which costs about $3.00 or so.
Noise—Brake noise can be associated with any wheel, front or back. It can be defined by a metallic (metal-to-metal) sound—a swish-swish or grating noise, coming directly from the proximity of the affected wheel. This noise is most pronounced when braking for a stoplight or sign, for instance. It frequently resembles a swish sound—this is a result of the rotation of the shoe or pad coming in contact with the drum or rotor. A constant metallic grating (or groan) would indicate that the pad or shoe lining is absent and the surface of the rotor or drum is in direct and constant contact with the shoe or pad backing mount (hard metal). To listen for it accurately, you can drive your car slowly next to a wall, which will amplify the noise.
Actually, to listen for bad brake lining one does not need a “dead silent” environment. Of all the suspicious noises emanating from an automobile, a brake noise is one of the most obvious. It can be quite loud even in city traffic. Sometimes a pad or shoe lining actually breaks away from its mount and causes an audible noise. This happens in frequently but it can still be heard as small clatters or jerky snaps and might be felt in the brake pedal underfoot.
Clicks and rattles may be the result of broken or worn return and hold-down springs—or a broken piece floating inside the drum. For these smaller and less audible noises, such as rattles and clicks coming from the wheels, use the technique of listening while driving against a wall slowly, such as alongside a building. But before you do it remove all the hubcaps on your car if it's so equipped. You would be surprised how many times hub caps pick up pebbles sending them zinging around inside rattling. If you have wire wheel hub caps, check to see that the wire rods are not broken and flopping, causing this noise.
Keep in mind that most brake noise happens when the brakes are applied unless a spring has broken and a shoe is dragging.
Any brake noise, especially the loud swish-swish or grating type, should be taken care of immediately. It means you are metal-to-metal and your ability to stop, especially in a panic situation, is greatly reduced! Brake drums and rotors are extremely expensive, and if you let the problem continue there is a good chance the drum or rotor will be permanently ruined. In many cases, you can only purchase new ones from a dealer, which means paying top dollar.
Squeals—Every car made today has front wheel disc brakes. The most common complaint in the noise department is the front wheel brake squeal or squeak. This squeal can be detected in the last stages of braking, and has been known to drive people up the wall.
It is an irritating, loud and inconsistent noise that comes and goes. I’ve lost count of the number of people who have sworn that they needed new brakes as a result of the disc brake squeal. And I’ve had to pity the hundreds of customers who went ahead and replaced their brakes because of this problem, or were told as much by shady mechanics. This noise is common and can almost be considered normal. It happens because the brake pads get hot and glazed. The glazed surface of the pad becomes sticky and hangs up, causing this squeal or squeak.
One place I worked for offered a front disc brake “squeal service.” It amounted to removing the front wheels, spraying down the pads with a brake cleaning solution, and in some cases sandpapering the pads to knock the glaze off. This “freshened” them up. We charged little for this service, the idea being that the same customer would then come back for a thorough brake job when it was needed—then we’d really sock it to ‘em.
Since this service is rather unorthodox I don’t expect that it's alive and well today. Mechanics of today like to sell you new pads, and this is just what they’ll tell you—”The brake pads are burned or overheated.” Well, I’ve never known any brake pad to stay cool under any condition, but a brake squeal does not mean that your pads are ruined. If you simply can't stand this squeak or squeal another moment longer, beg your mechanic to knock the glaze off your pads. Let’s hope he does, as a favor to you. Give him the money for new pads (a complete front wheel disc brake job) only when the lining is obviously worn, when he shows them to you. Don’t fall prey to the “burned” pads theory. Instead, keep a heavy foot off that accelerator and don’t ride the brakes from now on.
Brake Pull—Brake pull is associated with the front wheels of the vehicle. In most cases it's caused by “contaminated” brake lining. This is a situation where brake fluid has leaked onto the shoe lining or pad via a leaking wheel cylinder or caliper or a defective wheel bearing seal. The fluid or grease makes the contact of the brake lining surface slippery—the pads or shoe lining can't function by gripping and causing friction. If the leak occurs on one wheel, it won’t “grab” as well as the one opposite it, and the car will pull in the direction of the wheel without the fluid. If the pads or shoe lining have been contaminated or wetted it's always advisable to have them replaced and the primary leak traced and repaired.
A worn brake lining or badly scored drums or rotors can also cause brake pull. So can a sticking or defective front caliper piston or wheel cylinder. In the case of front wheel drum brakes, broken hold-down and return springs can interfere with smooth braking operation by binding up or breaking. In any event, a brake pull cries out for immediate attention and an inspection should be performed as soon as possible.
Soft Pedal—A soft or “spongy” pedal, a pedal that feels “cushiony” or un-firm when applied, can mean that air is in the brake line system. This happens frequently right after a brake job has been performed. Sometimes a mechanic fails to “bleed” all of the air out of the brake lines. It can be the result of a person who takes one of the wheels off his car and loosens a bleeder nut. When a vehicle owner has to pump up the pedal several times (to get brake height), this can also be the result of air in the brake line system. An empty or near empty master cylinder can cause a sponginess in the pedal or cause the pedal to travel all the way to the floor. Check the fluid in the master cylinder.
Brake Pulsation—If you apply your brakes and the pedal “throbs” under your foot, this is known as a “pulsating” pedal. Worn or loose wheel bearings can cause a drum or rotor to rotate sloppily, causing this pulsating condition. Rear axles that are bent or twisted can cause the hub to wobble, and since the hub holds the rear drum in position this leads to its periodic misalignment while rotating.
Drums or rotors that have suffered severe heat damage can become warped or eccentric (out of round). There is a rare condition in which a drum can blister from extreme heat, and just like a boil, it can produce a lump and cause a brake pedal chatter or vibration. Drums and rotors that have suffered this severe heat damage can normally be “cleaned up,” or cut smooth on a brake lathe.
Drums and rotors that have become overheated turn a brown or dirty color and give off a noticeable odor. They can become so hot they’ll heat up other components, such as rubber wheel cylinder boots and cups, grease and even the brake pads and lining, which are made out of asbestos materials. Braking your vehicle hard while towing heavy loads downhill, leaving the emergency brake on a few notches and hard-driving habits—all contribute to overheating brake conditions. With extreme heat comes metal and component warpage, thus causing a part to be misaligned.
Brake Drag—Brake drag is a condition in which your brakes don't release fully after depressing the pedal. This can be the result of a broken hold-down or return spring. A sticking by-pass port in a master cylinder can cause this condition and lead to the brakes dragging.
Sticking pistons inside the caliper or wheel cylinder can freeze up in a braking position and cause constant friction and contact. One of the most common problems associated with brake drag has been when a vehicle owner leaves the emergency brake on in a position where it actuates the shoes against the drums. Of course, if a mechanic has adjusted the rear brakes too tightly, this can cause them to drag— which builds up heat, causing them to expand and drag further.
A condition of hot and dragging brakes is a serious one that can lead to enormous expense. You can tell your brakes are dragging because you’ll often smell it. The smell is an acrid, sharp odor. If you pull over you might spot smoke coming out from the affected wheel. If a vehicle is operated with dragging brakes for a time sufficient to put strain on the engine, it's entirely likely that the automatic transmission could suffer major component damage. Transmission clutches could burn, and delicate seals could burst causing an immediate loss of transmission fluid. If you experience this condition while on a trip or far away from a service center, pull over, stop and seek immediate repair assistance. If no assistance is available it's wise to let the brakes cool off before proceeding any further.
Fluid Level—Any time the brake master cylinder fluid is low, or nearly empty, fill it up. If it drains quickly, it's time to inspect the condition of the wheel cylinders, calipers and brake lines, because a sudden and frequent drop in fluid level is an indication that there is a probable leak in the brake system. A preliminary check would be to look at the inside surface of each wheel to spot any fluid leakage. The inside surface of a tire that's soaked or splattered with brake fluid will appear blacker than any other tire.
A master cylinder can develop a leak in the rear seal of the master cylinder body or the line connections to it. A defective rear seal in a master cylinder will show up as a wet spot or stream of fluid against the firewall directly underneath the cylinder body. If this condition is found (low fluid level) in the master cylinder, fill it to its proper capacity and then take the vehicle in for an inspection. If you lose all fluid, then you’ll quickly lose your brakes, which can spell disaster. It is unwise to assume that there are no leaks when having to fill or add fluid to the master cylinder.
Don’t let anyone sell you a brake master cylinder because he says it will complement the new brake job he s just sold you, or that it's necessary because you have to do it when the brake pads, shoes and rotors and drums are replaced and machined. A bad master cylinder will produce a brake pedal that goes all the way to the floor with increased and steady foot pressure They can a/so be diagnosed as bad when they are leaking from their rear seal—fluid trails down the front of the power assist or down the firewall (not to be mistaken for spilled fluid which gives an almost identical visual symptom) When confronted by this, demand to see the leaking cylinder, and to see evidence of the leak in the master cylinder’s area If the leak is at the wheel or in some brake line elsewhere, there s a good chance the problem is not with the master cylinder.
Generally speaking, it takes a tear-down inspection to determine accurately what condition your brake system is in. This means removing the wheels and checking the thickness of the shoes and pads, as well as the thickness, roundness and surface condition of drums and rotors (the “disc”). It should include checking the brake lines, wheel and master cylinders for brake fluid leakage. The hold-down hardware (the small pins and springs that hold your brakes in place) must be visually inspected for strength and reliability. This includes the nails, hold down and return springs, emergency brake lever, cable sleeve and operating link. Front wheel brake calipers must be examined to determine if the internal pistons are free-moving.
Usually, there is no charge for a brake inspection. In a few shops there could be a minimum shop service charge to determine the fault in the system only: this cost would be in addition to the repairs made. I would avoid a shop that charged for an inspection, there are too many facilities around who will perform this service free of charge.
Brake Linings—The first thing a mechanic will inspect is your brake linings—the thickness of the pads or shoes.
Generally, it's time to replace your shoes or pads when you have about 30% or less lining left. This 30% limit seems to be the rule of thumb with used car dealerships because they consider this to be the cut-off line for replacement. Many dealerships have been prosecuted in the past for selling used cars with less than adequate brake lining. Other repair facilities might want to raise that figure to 40% or 50% lining left as the rule to replace brakes. I would choose to put more miles on my brakes rather than have them replaced at the halfway point.
But determining when they need to be replaced can be tricky. A good mechanic can eyeball brake lining and know exactly what percent is left and estimate how many more miles they will last. He could very well examine your set of brakes and know that you have 50% lining left but he could say 30% is left. And how would you know? You can demand that he give you a side-by-side comparison of your worn brake pad or shoe and a new one. Then you can eyeball it yourself.
So what if the mechanic shows you that the left front pad is worn, the right pad is okay, and the rear shoes are okay, but he says you have to have a four-wheel brake job because you can’t have some new pads/shoes and some old ones He s half right You should recondition your brakes in axle sets. In other words, in the above example, both front brake pads should be replaced even though one is okay. However, if the rear shoes are fine, then they don’t need to be changed at all. The same could be said/f the fronts were fine, but the one rear shoe was worn. You can leave the fronts alone, but must change both rears. Don’t fall for the scam of “you must always recondition and replace all four brakes at the same time.” The front brakes on front-engined cars wear out almost 2 times faster than the rears.
Also, remember that during inspection, the mechanic will look for the wheel with the most worn lining and base his percentage judgment on that wheel. You could have 60% lining left on three wheels and 30% lining on one wheel, yet he will pass judgment on that bad wheel and recommend that you purchase a complete brake job. In a case like this, you would only need to replace the axle set with the 30% lining, but not the other axle set (see the sidebar on p. 87).
Many new cars have an electronic sensor that warns the owner of a brake lining deficiency via a dash light. These type of brakes come with a sensor wire embedded in the pads and when the lining wears to a certain point the information is relayed to the driver.
Disc Brake Pads—Most all cars have disc brakes in the front, some have them in the rear as well. The proximity of the pad mounting plate in relation to the rotor is the distance that determines the thickness of the lining. The asbestos pad on disc brakes wears in direct proportion to its use and age. A normal new disc brake pad is about 1/2-inch thick. When it approaches a thickness of about 1/8 inch it's near to replacement—or obviously when it's completely gone—causing a metal-to-metal condition. The mechanic will also advise that you re place your brake lining if it has become contaminated or wetted by brake fluid or bearing grease. Contamination means that the fluid or grease has permeated the porous material of the brake lining, rendering it ineffective. Once they are soaked they have lost their true ability to cause adequate friction. So in a sense, just a small amount of fluid on one pad could cost you a two-wheel brake job. Old brake fluid also has a habit of deteriorating some fibers and materials with which it comes in contact.
Drum Shoes—If your car is equipped with drum brakes (the majority of cars today are equipped with front disc/rear drum brake systems, although many performance-oriented and some upmarket cars are equipped with 4-wheel disc brakes), then the rear brake shoes need to be checked. They are inspected in the same manner as the front disc brake pads—with the rear wheels and drums off. The relative thick ness of the lining on both shoes, on either wheel, determines their condition. Since drum brake shoes are larger (more surface area) they are not as thick as disc brake pads when new. When new, they are approximately 3/8 of an inch in thickness and can wear until they are paper thin before contacting the metal rivets that hold them on the shoe frame. When it wears to the rivets, shoe lining will always make a metal-to-metal noise. Any shiny metal surface on a brake shoe indicates that it's worn beyond its capacity to function.
Wheel Cylinder—In addition to checking the pads and shoes a mechanic should also look for a leaking wheel cylinder. The wheel cylinder (in the case of drum brakes) is located near the top of the backing plate and bolted to it. It is similar in size to a “D” type battery. Inside the cylinder are two cups and two pistons. It is the piston’s job to expand the brake shoes so they make contact with the drum. The pistons are forced outward by a surge of brake fluid when the brake pedal is applied. The cups inside the cylinder are responsible for keeping the brake fluid within, acting as a seal or retainer. Once these cups have worn from repeated action they lose their elasticity and allow brake fluid to pass by, through the dust boots on the end of the cylinder body and onto the brake lining and parts. A mechanic has only to remove a dust boot to see if the interior of the cylinder edge is wet. If it shows just the slightest amount of moisture he will recommend that it be replaced or rebuilt. A typical cylinder rebuilding kit will contain two new dust boots, two cups and a new return spring (the spring is located between the pistons).
Calipers—The mechanic should also check the condition of the calipers. The calipers are what “squeeze” the brake pads onto the rotor when the brake pedal is applied. They have a cylinder with one large piston in it (some exotic sports cars have more than one piston). An “O” ring seals the piston to the caliper housing. Like a wheel cylinder, the caliper has a dust boot that can be pulled back to check for internal leakage. A caliper is rebuilt much the same way as a wheel cylinder, only there are no cups, just an “O” ring and a new dust boot per wheel.
Wheel cylinders and calipers are parts often pushed onto an unsuspecting customer. Few people realize they can be rebuilt at a substantial savings over new items. If the seals are leaking, don’t be pressured into purchasing new ones by a mechanic who insists they can’t be rebuilt, If he finds a leaking wheel cylinder he is apt to sell you not one, but a whole set. Why? Because they bolt on very quickly—the profit margin is higher, and you’ll probably go for it after they scare you with “you don’t want to take a chance on brakes”.
In the case of rebuilding a caliper, sure, it’s a hassle, and it’s a hassle that he’d like to avoid. Even when this service has been included in the standard advertised brake job, I’ve seen mechanics smear oil over the dust boots to give the impression that it has been done. Especially the caliper rebuilding. It takes awhile to get a new seal around that piston and back in the caliper housing. Calipers require additional tear-down time.
Rebuilding Calipers and Cylinders—Find a shop that includes this service in their brake package. Insist, if necessary, that it be per formed, or better yet, stand within visual distance and make sure that it's ! About the only legitimate excuse a mechanic can have for replacing your wheel cylinder (not rebuilding it) is if the inside of the cylinder body is pitted and scored from age and dirty brake fluid. The inside of the cylinder body can always be honed out to clean rust and grime away. But if the metal bore surface is pitted and eaten, it will not seal with new cups; therefore it should be replaced.
Measuring Drums and Rotors—The next inspection the mechanic will make will be very important. He should, if he has been trained properly, use an inside micrometer (that is preset to the drum diameter) to measure how much surface material is left on the inside of the brake drums. It is a measurement that denotes the inside diameter of the drum and is usually expressed in thousands of an inch, i.e., .060 or .090. An outside micrometer is used to check the thickness of the rotor because it's a disc and must be measured externally. If the drums or rotors are to be machined, there must be enough material left to machine out scores and pits and still remain within the minimum tolerance.
The minimum tolerances are specified by the manufacturer. If, for instance, a drum diameter exceeds that allowed by the manufacturer, it must be replaced because policy and law dictate this. That is why it's important for a mechanic to actually use the gauges to make these accurate and critical measurements. Just one false reading on one drum or rotor could mean the difference of $90.00 on your repair bill. Too many mechanics want to eyeball these parts and make snap decisions on their appearance alone. For example, a drum can look terribly chewed up and scored on its inside surface but miraculously it can “mic out” and fall within manufacturers specifications, particularly if the vehicle is new. Many drums and rotors that have been scored will clean up after several cuts on the brake lathe.
If you are told that you need a new drum or a new rotor, the mechanic or manager is obligated to prove it to you by revealing the measurement, and recording it on your invoice as further testimony. If in doubt about the condition of one of your rotors or drums, ask for this proof of service and legitimacy. If they say that the wear exceeds the minimum tolerance, ask to see the written tolerance specifications in their manual. If they refuse, then you are probably being scammed. Go some where else.
Shoes and Pads—If you’ve been convinced that the brake shoes and pads (linings) have been honestly inspected and you agree they are worn, you’ll have to choose what type you want. If the mechanic doesn’t ask, you should ask what type they are. The two most popular types of brake linings are the asbestos type and the metallic type. Metallic brake shoes have small bits of metal molded into the shoe surface which makes them very durable and long-lasting. This is fine except that this type of brake lining is a bit noisier and more likely to squeal for a long time before it “beds in.” The metal surface will also wear out your drums and rotors quicker. Unless you do a lot of hard, fast performance driving, my advice is to stick with the standard or regular asbestos variety of brake lining. Though you will not get the mileage out of them that you would the metallics, they are much easier on your drums and rotors. Standard lining also costs less.
Combi Kits—As a mechanic I used to call them combi or combination kits. These are the little springs and hold-down hardware needed to assemble and keep the brake pads and shoes in place. Among some of the pieces are the return springs, nails, hold-down springs and spring seats, hold-down retainers, anti-rattle springs and retainer clips. The packages come for either front disc brakes or rear drum brakes. Most of the pieces work on a spring or spring/wedge principle. The packages can cost anywhere from $10.00 to $15.00 per set. These pieces don't wear so much as lose their tensile strength, and that's really the only reason why they should be replaced—if they lose their tautness or spring. In the case of rear drum brakes, combi kits are designed to push the shoes onto the drum when the brake pedal is applied and pull them back away from the drum when the pedal is released. When a mechanic disassembles brakes, using his special brake tools, he can tell instantly, by “feel,” if the springs have lost their strength. He can also observe how snugly the shoes fit against the backing plate by pulling on them, testing their resistance. And many times, he will overstretch a spring himself, or lose one during disassembly.
The fact is, combi kits don’t have to be replaced as often as the mechanic usually replaces them. These are the little knick-knacks in a shop’s inventory that bring in extra cash flow, above and beyond the price of a standard brake job. If you are confronted by a mechanic who wants to sell you this brake hardware for all four wheels, I would ask him to show me at least five or six stretched or mutilated springs out of the dozen or more on the car.
Too often a mechanic will find one weak spring on one wheel then profess that you need to buy the whole kit because it's preferred to have opposing brakes operating in “identical” fashion. Not only that, he can give you a “scare” line and say that it's very important to safety. I know of mechanics who did just this because they received a small commission for each combi kit sold. The fact is, many mechanics have boxes of extra brake springs, retainers, clips, etc. that are in perfect working order just lying around the shop. He wouldn’t think of giving you another spring, but instead he wants to sell you the whole she-bang, a complete set.
The fact that your springs are bad, or ever will be, is a little slim. They hold their tensile strength amazingly well. I’ve seen cars with well over 100,000 miles with the original combi kits intact and working perfectly. But if it so happens that the mechanic can show you a few over-stretched springs that are not performing their function, yes, make the purchase, but not for both rear wheels. Buy one set for the wheel that has the bad springs. These springs actually should be included in an advertised brake special. Look for the phrase “all minor parts included.” When you get to the shop, ask if minor parts are defined as springs and clips. If not, then ask for them to be included. These items are often negotiable, because their cost is negligible com pared to the price of the brake job.
Anchor Blocks—Mechanics refer to anchor blocks as “adjusters” or “stars.” They are little cylinder-type devices located at the bottom of the brake shoes. They expand or contract when adjusted with a brake spoon. This is how the rear brakes on your vehicle are adjusted. However, these anchor blocks often become frozen or immobile. Dirt, water and grime can get into the delicate threads and jam this component, thus making it impossible to adjust your rear brakes properly. But this can be easily corrected by cleaning the adjusting nut and bolt. More often than not, it will work perfectly. Do mechanics do this? Some do; some don’t. If a mechanic told me that I needed a new anchor block because he couldn’t adjust my brakes I would ask him if he cleaned it. All you have to do to clean it's remove the wheel and drum then detach the anchor block by spreading the brake shoes. I’ve never seen an anchor block that wouldn’t come apart for the purpose of cleaning. There is really no need to buy one—they are dealer only parts in most cases anyway and the wait and charge for one could be considerable.
Backing Plates—A backing plate is what your rear brake shoes ride against and it can be faulty when worn. It can only become worn by the repeated action of the brake shoes, which will cause a cut or groove in its surface. This happens in much older vehicles and I would be leery if somebody told me that my backing plate was bad, when I was in possession of a nearly new vehicle. Besides, with a standard brake job the backing plate is routinely wiped clean and lubricated in these spots. It had better be... it’s part of the brake job.
What exactly is involved in a brake job? That depends on what you’ve negotiated up to this point. Some shops offer “complete” brake job specials, but often hidden between the included items are additional charges for services that are necessary but not part of the deal. In worst cases, some services are offered and charged as part of a package but not performed. The following is a list of services that should be included in a standard brake job. If they aren’t, then insist that they should be or find somewhere else that will perform them.
Bearings and Grease Seals—A mechanic doesn’t necessarily have to pack the front wheel bearings as a complement to a brake job, but it's a service that should be done at the same time.
Most front drum brakes are on the older vehicles. When the drums are removed from the front wheels there is easy access to the inner and outer bearings of each wheel. In fact, they are right there in plain sight. It does not take any time at all to pack these bearings with new grease, but all too often a mechanic will service the brakes and assemble the wheels without so much as smearing grease on the bearings, let alone packing them.
When the rotors are removed for the purpose of turning, the bearings must be removed and set aside until reassembly. Why can’t a mechanic make it a stiff rule to pack the wheel bearings when they are conveniently off the wheel? It takes about five minutes to accomplish the task. If the service is included and appears on the advertisement or coupon it's absolutely essential that they do the work prescribed. Wheel bearings are important. They are under heavy load and pres sure, must turn constantly and are subject to extreme heat.
How would you know if your wheel bearings have been packed after a brake job? Real easy: remove the hub caps on the front wheels of your vehicle. You will see a small cup-like cover in the middle of the wheel; it's about the size of a small Dixie cup. Pry this cup off using a screw driver and look inside the hub. This area is where the outer wheel bearing is seated. If a mechanic has packed the bearings you will see evidence of new grease—new grease is sometimes yellowish or a clear dark green. The new grease should be in profuse amounts on the outside of the outer bearing. Little or no grease or grease that's black is an indication that no bearing pack has been done. If you find that this is the case, and the policy of the shop is to pack the bearings with a brake job, or worse yet, you have been charged for a bearing pack, take the car back and insist that they do the work. Then have them initial it on the invoice for your satisfaction.
Grease seals come with calipers and drums. These seals keep the bearing grease contained inside the hub so it doesn’t travel up the spindle and splatter all over the new brakes. Some shops supply grease seals with a standard brake job. Others don't and want to charge you extra for them. Find a brake special that includes grease seals in the deal, if at all possible. If not, make mention to the service manager or mechanic to check the seals to determine if they are in good condition. While you’re at it have them examine the rear axle seals to make sure they are not leaking. An axle seal that leaks will ruin a perfectly good set of brake pads or shoes. Who pays for the brakes if they miss this inspection and as a result your rear lining gets contaminated? They pay for the shoes but you pay for the labor to install them!
Turning Drums and Rotors—If the drums and rotors are deeply scored with ridges deep enough to catch your fingernail, they should be machined smooth. This is referred to as “turning.” It is done by securing drums and rotors on a driveshaft where they spin and come in contact with a diamond tipped bit. The machine has two cutting modes: a rough cut (initial cut) and a fine (final cut). It is the mechanic’s job to make as many rough cuts as necessary to obtain a clean smooth surface on the drum or rotor. These cuts are usually made in increments of two-thousandths of an inch. A scored drum might take a cut of eight- thousandths of an inch before it's cleaned up. Then an additional fine cut of two-thousandths to finish it.
Generally, any metal cut more than ten-to twelve-thousandths is exceeding allowable tolerances and sometimes they find this out after the many cuts. Therefore it's quite possible that your drum or rotor did mic out within specification, only the mechanic found out later that it required too many cuts to “clean it up.” In this case the shop should notify you and get your verbal approval for the additional expense. This happens sometimes and it's really not the mechanic’s fault. Some drums and rotors are scored so unevenly that it's difficult to get an accurate measurement on them. If this should happen, you have every right to demand a measurement of your old drums or rotors when you pick up your car.
Quite often you’ll be told that turning rotors and drums is absolutely necessary for all brake jobs. Quite often, it's included in the entire brake price. However, if the rotors and drums are not pitted or scored, it's not absolutely necessary. With heavy brake use, such as in frequent stop ‘go traffic, the pads and shoes will wear much faster than the rotors or drums. Therefore, it/s possible that you’ll only have to replace the pads and shoes, and perhaps have the rotors and drums turned every other brake job.
Although I haven’t seen too many drums or rotors gouged, burned, or ruined by a mechanic who didn’t know what he was doing on the lathe, the possibility does exist that a drum or rotor will catch sharply on the machine and stop suddenly. This is because the initial cut in the drum has been set too deep—usually. If you are standing in view of the brake lathe and this happens to one of your drums or rotors and you find out later that this drum or rotor is ruined, then this is obviously the cause, the mechanic was at fault. If you are witness to this, and the drum or rotor is ruined, you have cause for litigation.
What happens all too frequently on the brake lathe is the habit of a mechanic to leave out the fine cut entirely. The reason is that the fine cut takes twice as long to accomplish as the rough cut—the cycle time is doubled. A mechanic in a hurry runs through several rough cuts, checks for smoothness, then pulls it off the lathe. This is a heinous shortcut. The fine or smooth cut does a much better job of cutting a true hard profile into the drum or rotor surface. Smoother and cleaner metal is not as porous. A fine cut produces a firmer, and more positive contact between the drum/rotor surface and the brake pad/shoe. It should always be mandatory. Rushed mechanics don’t seem to like waiting around near the brake lathe for a drum/rotor that's taking its sweet time on the fine cut mode. For years, they’ve been getting away with rough cuts alone. Make sure you get a rough and fine cut if your drums and rotors are going to be turned.
Arcing Shoes—While we’re still at the brake lathe let’s talk about arcing or chamfering the rear brake shoes. Rear brake shoes resemble half circles; they have a curved arc. This arc, on new shoes, is supposed to fit precisely into a drum that has just been turned on the lathe. Many times the fit is not precise and thus the shoe must be arced on the brake lathe machine. The section of the machine that handles this chore has a saddle for the shoe to sit in. A handle is used to move this saddle back and forth, pushing the shoe into a rotating abrasive disk. In this manner the shoe is sanded to the exact same arc or fit as the inside curve of the drum. What do you have? You have a perfect and complete fit with little or no error. It means that the inside drum surface is making 100% direct contact with the shoe—total braking power.
Here’s the sad part about arcing shoes. I would estimate that as many as 70% of the mechanics don't perform this function at all. Besides taking additional time, besides being a chore that's mandatory, be sides the fact that it ensures safe and adequate brakes from the start, the mechanics have told me that “what the hell, the shoes will break in themselves.” This statement is typical of a repair sham. I’ve conducted many experiments by installing brake shoes that were not arced on a vehicle, taken the car for a test ride, returned to the shop and inspected the results. In every case the new shoes were hitting (making stopping contact) on the outer edges of the shoe lining—a total braking surface area of perhaps 40% of its designed 100% potential. The shoe lining must be custom fit to the arc of the drum, especially after the drum’s profile has been changed by cutting it on the lathe.
The statement that the shoes will arc themselves is correct in a primitive sort of way. But it might take thousands of miles for the shoes to seat into the profile of the drum, especially if they haven’t been mated to the drum via the arcing procedure. Will it take 1,000 miles to seat, or will it take 6,000 miles? That depends upon how bad they were out of fit to begin with. Why should a customer have to endure a loss of 60% braking efficiency for even a short duration? The reasoning that it will soon be over because the shoes will seat in a while or that the customer will never know, just doesn’t hold water. I don’t care if they are new shoes, if they are not arced and mated precisely to the drum, the braking power will be reduced. If per chance the mechanic has also left his greasy hand prints on the lining of these non-arced shoes, that car is going to be more difficult to stop than if the job had been performed right. Is that any way for new brakes to be installed on a vehicle especially when you’re paying a king’s ransom for the job? I think not. You might have had more braking power on your shoes before that bad job was performed!
Insist that the chore of arcing the shoes to fit the drum be performed. This chore is not in the category of extra amenities; it's crucial to the effectiveness of your brakes and should be mandatory.
Bleeding Brakes—There are two ways to bleed brakes on a vehicle. One is the manual way involving two mechanics: one mechanic under the car who opens the bleeder valves to bleed out fluid, and the other who sits at the wheel and pumps up the brake pedal to force the brake fluid through the lines. This manual type of operation is very primitive and takes a great deal of time and coordination on the part of both mechanics. It is more subject to human error. Two mechanics just can’t seem to get into perfect sync all of the time and as a result one yells “pump em up” and the other mechanic doesn’t hear him, or some other mis-cue. As a result, air often stays in the lines no matter how hard these two try to get it out, and this leads to a spongy pedal. The two mechanics conceivably can spend more time, which leads to a higher labor charge, repeating the bleeding for each wheel and still end up with a few air bubbles in the system. They also have to constantly refill the master cylinder. What’s more, there is no guarantee that they will flush the lines completely and remove all the old brake fluid. Fluid breaks down in viscosity and chemically. What happens when brakes are bled manually is that not all of the old fluid gets flushed out of the system. In a sense, the old brake fluid dilutes and contaminates the new fluid that enters the lines.
The other way to bleed brakes is by using a power bleeder (a pressurized tank containing brake fluid and connection adapters). By placing an adapter over the master cylinder of a car, a mechanic can turn a valve and produce a steady pressure in the brake lines by which he can bleed off the individual wheels at his leisure. If you saw two brake special ads and one said “bleed and adjust brakes” and the other “power bleed and adjust brakes,” go for number two. When a system is power bled using the pressurized tank, a constant and steady flow of fluid is delivered which forces all the old fluid and air out of the system. This is precisely want you want—brand new brake fluid in the entire system without air bubbles.
Road Testing—Most repair facilities don't road test each and every vehicle to see if the repairs made solved the problem—but they should. I’d want my vehicle driven for a few miles with the new brake job to insure it was braking at its maximum potential, that there was no air in the lines, and that it had a good high and firm brake pedal.
Learn to recognize the symptoms of faulty brakes—low brake pedal, brake noise, spongy pedal, rapid fluid loss in the master cylinder (wet wheels), brake pull, pulsating pedal and brake drag.
It is time to replace your brakes when you have 30% or less lining left. Have the mechanic show you the comparison of your brake shoes or pads versus new ones. Remember, shoes/pads only need be replaced as axle sets, i.e. both front or both rear. Don’t be talked into a “mandatory” four-wheel brake job.
Even new brake lining on your vehicle can become contaminated and ruined by leaking fluid from a worn wheel cylinder. Check inside tires for oily wetness.
Your car might have electronic sensors in your brake lining that tell you, via a dash light, when your lining needs replacement. Check your owner’s manual to see if you have such a system on your car.
Wheel cylinders and calipers can be rebuilt economically and they don't have to be replaced except past the point of repair. Insist on rebuilding first before purchasing new ones.
If a mechanic tells you that your drums and rotors are bad you should ask him to prove it by checking the specifications in his shop manual and by showing you his measurement on the drum or rotor itself.
Find out if there is a shop policy regarding used drums and rotors if you happen to need those parts and would like to obtain them for yourself. Ask if they allow you to locate these parts and if they would agree to install them on your vehicle as part of the brake job.
Brake service is one of the most lucrative tickets in a bonus shop. Monitor the operation very carefully and ask questions about anything that seems confusing or misleading.
When checking a brake special ad pay attention to the services offered such as: rebuilding wheel cylinders, road testing, grease seals, bearing packs, power bleeding and warranty/guarantee.
Drums and rotors should receive a fine (final) cut on a brake lathe. Make sure the shop performs this service—they often don’t.
Make certain that your new brake shoes are arced. Arcing insures 100% shoe/drum contact. This service is often skipped by hurried mechanics.
If the mechanics are pushing the combi kits (hold down hardware) on you, there must be a reason. Are all of the springs bad? One bad spring? Does he have an extra? Combi kits are often a negotiable item.
Make sure that your brake shop offers the power bleed service, and that they carry the highest quality brake fluid.
Most anchor blocks are easily serviceable. Request that the shop disassemble and clean these parts before you’re talked into purchasing new ones.
For those who do their own brake jobs, be aware that dismantling and pi yards sell used drums and rotors. Many auto parts stores turn used drums and rotors for you.
Know the difference between metallic (long life) brake lining and standard. Standard asbestos lining is sufficient for any vehicle.
Ask for your old brake parts. If you don’t get your old parts, sometimes a lawyer can't help you with litigation if they don’t have some physical evidence. It pays to be prepared.
Ask for a warranty or guarantee in writing. They should come with every brake job and some are better than others. Note whether the shop provides free follow-up service on your new brakes, such as checking and adjusting them at regular mileage intervals.
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