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Time to Stop

By

Dennis R. Franklin
Franklin's Tire and Suspension
Yuma, AZ

If youíre reading this you probably donít want to know how to do a brake job. But if a technician says he wants $300.00 to replace a whole bunch of "stuff" to repair your front brakes. And all you wanted was the $49.95 brake job. I would think you might want to know why. I therefore need you to understand how brakes work and what their components consist of.  I have seen more brake jobs where components are sold that didnít need to be replaced. I have also seen more customers turn down the required repairs. Why? Because the customer didnít know any better. We also have a problem with the people that work in the shops too. They need to be able to communicate in laymanís terms, what is need and what isnít. Most conversations go like this; "You need brakes"! Customer; "how much", technician; "$300.00"  customer; "too much, can you do it cheaper" answer, "I need to replace the gadget that connects to the widget and if I donít the gadget may wear out too soon. I could just replace the wooziest with out it but your warranty would only be a year. Customer says, "well how much is that"? Technician;" $89.95" customer; "Ok do it, when will it be done?" Did you understand all that? Now the fun begins. 6 months latter the customer comes back with a complaint. Technician says; well I told you we should have changed the gadget and the widget". Letís face it technicians, even the best ones, are not trained to talk to customers. I canít educate all the techs but I can give you enough information to be able to make an informed decision. How hot is hot, brakes that is?

READ ALL ABOUT IT,  BRAKING HOT NEWS

No matter how old your vehicle is or who built it they all use the same principle to stop. They all use a form of friction to convert forward (ok, rear too) motion to heat. How much heat is a matter of physics but to simplify it the gas that was burned to provide the forward motion minus energy lost in the engine, drive train, rolling and wind resistance equals how hot the brakes will get. Depending on the vehicle, the front brakes will stop most of the vehicle. So talk about hot, front wheel drive cars can exceed 1000 degrees on the front brakes. Every component in a brake system down to the type of grease used is made to withstand the high temperatures.

I should re-phrase that and add "for a time". Because as we all know, heat destroys- eventually. The items that get really hot are the ones that weíre going to be looking at.

Friction material Ė you can call them pads or you can call the shoes but these are the things that wear out. The "lining material" as we call it in the industry has as many different qualities and processes to put them together as there are with tires. The big difference is the way they perform not just wear. (Sounds familiar)? Manufacturers rate friction material with codes like "EE", "FF", "EF"etc. these ratings tell us not how long theyíll last but how they handle heat. When brakes get hot they hold with a certain grip but they start to loose this ability if they get too hot. This is called brake fade. To the driver, as the brakes get hotter and hotter, will have to push harder and harder to stop the vehicle. A lower grade lining material will as a rule fade out a little quicker. How fast the heat transfers, the absorption rate and in some cases isolation tendencies, brakes dust and noise are all factors in grading. Have you ever noticed brake pads advertised for $9.95 and with a lifetime warranty? Factory pads or the guy down the street wants $59.95 for the same thing right. Not even in your dreams will they be the same. The more a manufacture puts in and the additional processes they go through determine the price. Factory pads and some premium pads go through a process called "burnishing". This process cooks the pads, curing them so they can be put to immediate use. Lower quality pads miss this step; they let the customer do it. Most shops will advise the customer to be easy on the brakes for a few days. Reason, if they get too hot during the "break-in period" the bonding agents will liquefy and flow to the hot spots of the material. That causes squeaks, large amounts of brake dust, rapid wear and generally unhappy customers. Remember, if itís too good to be true it probably is. There are specialty brake products for people that use their vehicles in a commercial or heavy loaded condition too. Here is a little tip for you. If the manufacture not the seller warrants the product itís probably a good product. If the seller of the product warrants the product be careful. 

The other major part in the braking system is called a disc or rotor or it could be a drum. In any case the friction material grips or pushes against these to stop you. They too get very hot and thatís why were going to look at these in a little more detail. Sense almost every car on the road sense the late 70ís has disc brakes Iíll focus on that first.

If youíve ever seen the front of your car with the front wheels removed, you have undoubtedly seen a big shiny metal disc. Thatís what we in the industry call a rotor. Itís not just a hunk of machined iron itís a very finely engineered hunk of machined iron. The engineerís design them to be matched precisely to each car weight and configuration. How? If you guessed temperature you guessed right because thatís the main factor in any brake system design. The object is to make the brakes as lightweight as possible for each car. Factors like riding qualities, cost, fade resistance, longevity etc. make up some of the reasons why theyíre designed the way they are. At this point your probably asking yourself why do I need to know all this, why is he telling me this. Because when you get a brake job and a technician comes to you and says, "you need rotors" I need you to know the reasons why. Without that kind of understanding you can get ripped off or worse, make a very bad decision. Because of the need to make rotors as lightweight as possible they can only tolerate a very small amount of wear. To give you an idea how much wear, take a business card and fold it in half. See how thick that is? If measured, it would be about 15 thousandís of an inch. On average thatís all you can wear off each side before they must be discarded. There are many reasons why you can only wear off so little but the main reason is Ėheat. The thinner the metal is the less heat it can absorb and dissipate. The brake pads (friction material) would get too hot and cause the brakes to fade under hard braking. Also the brakes start to shudder or pulsate because the rotors have heat warped or created blue hot spots.

Some questions we will try to answer for you.  Do you have to machine (turn) rotors? Will grooves in my rotors cause a squeal? If one is bad do you have to change both? Whatís the difference between a $ 20.00 rotor and a $50.00 rotor? Is there a difference?

Above we looked at brake rotors them selves and kind-a how they worked. But letís, for the sake of argument, say you are having a brake job done and the technician says one rotor is beyond itís service limit and must be replaced, the other rotor although still within the manufactures specifications, must also be replaced. Is this a rip off joint? Is this shop trying to retire on me? Letís take a look. If we have a new rotor on one side and one that is very worn but still serviceable on the other, a small problem can develop. Remember our enemy, heat. During a braking operation the side that has the worn rotor will run much hotter causing it to loose itís braking effectiveness faster then the opposite side. How we have a brake pull. This becomes most noticeable during hard braking, panic situations, going down long grades or trying to stop a heavy load. Well it appears the answer is no, theyíre not trying to rip you off. The technician is just trying to do it right. This doesnít mean there isnít a few out there that take advantage this. Just because one rotor must be replaced does not mean the other has to be replaced. There are specifications from each manufacture that tell us what to do. If a shop canít show you in writing what the specs are, itís time to move on. But if you have to replace them, again, care must be taken because there is a difference in the quality of parts. Discount auto parts stores will for the most part only stock what we call "white box" parts. These are parts that are manufactured in China or other obscure Asian countries. Thereís nothing wrong with these parts other than they are not made with the same materials and they may not be balanced. As a rule they will wear out much quicker and seem in some cases to heat warp easier. I have even seen brake rotors and pads wear out at about the same time. This doesnít seem to happen to the higher quality name brand parts. I guess the old adage "if itís to good to be true it probably is" applies here as well. Most good shops will always try and use the quality material; they canít afford a bad reputation and not so happy customers. On the other hand, none of us want to spend a dime more then we have to. Theyíre not trying to rip you off. Now, that being said, there are shops that charge the brand name price but put on the cheaper product. All I can say is be careful, be a wise shopper, and ask around. 

Remember that this report is provided as a free public service of this web-site. The author is not an employee of either provider and has no association with either. Information is considered to be accurate to the best of our knowledge. As of the above date the information is Copyrighted, the sole property of the author, and unauthorized reproduction is prohibited.

Drive safe,

Dennis R. Franklin

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This page was last updated on October 13, 2002