Brake Pads

blackfang said:

Working in the auto field for the past 3 years, I also don't buy into the rotors don't warp theory. Juston explained it prefectly when you turn the rotors.

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No actually he didn't explain anything. All he said is that he had to dial in the cross slide on the lathe untill it cleaned up the rotor. The reason he had to do this was because the pad material was deposited unevenly on the rotor. This caused areas of the rotor to wear uneven. The rotor did not warp. Every time you hit the brakes you transfer some pad material to the rotor. It is a on going cycle. This material is removed to be replaced again. If the pad get too hot for the compount it will deposit in some places and not in others.Then the rotor is warn rather than the last coating of pad material. This causes spots in the rotor to be thinner than others. There are several other factors like imprinting and carbide build ups in surface areas of the rotor. These can all contribute to the uneven wear of the rotor. Proper break in is still the most important thing.

I dont and never have worked for pep boys.

I understand what you are saying about the pad wear and transferring it unevenly. What I don't get is you are saying there is no way ever that a rotor can warp? It's not like I dont work with 20+ year master and senior master techs and this is the first I heard of it

blackfang said:

I dont and never have worked for pep boys.

I understand what you are saying about the pad wear and transferring it unevenly. What I don't get is you are saying there is no way ever that a rotor can warp? It's not like I dont work with 20+ year master and senior master techs and this is the first I heard of it

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Its quite simple... Do you turn the hats? No. Thats because it doesnt warp. the rotor wears unevenly. If it was warpage them the hats would also warp. What you people think is warpage is uneven wear. You can check the thickness all over and you will find that you have thicker spots and thinner spots on the rotor. To the untrained eye you will think the rotor bent. It didnt. When you have a spot on the rotor that has no pad material cast on to it you get more rotor wear in that spot. When you have even disposition of pad material then you get even rotor wear. Incorrect pads for the temp application will not deposit evenly as they exceed the temp rating. Other things that can cause uneven wear is imprinting. Holding the brakes on when the pads and rotors are very hot will cause the pad to stick to the rotor and deposit a imprint of the pad on the rotor. This gives you a spot that will not wear the same as the rest of the rotor and now you have a thicker and a thinner spot. Next as you over heat the rotor you will have the carbon in the rotor forming carbides (Very hard spots.) These hard spost will not wear the same and will also cause thicker and thinner spots. not warpage!
Last point. If the rotor warped you could not turn it to fix it. You would end up with much thinner wall thicknesses in relationship to the inner walls. You would either have a really bad vibration from the bad balence or you would have to balance the rotors before you reinstalled them. Do you balance the thousands of "Warped" rotors that you turn.. I dont think so. Maybe you should talk to the 20 year experts you have and really think about the things that are taking place during braking.

everything that you have said Mr. Duke has made perfect sense to me.
i work at pep boys, and i know that compaired to people like you, i know next to nothing. but as for the other people at my work....well they make me look like you.
but there is one thing that i noticed there, when we get a shipment of rotors in, with some of the ProStop (china) rotors, you can place them on the table and actually see that they are not strait. people bring them back to be turned, and they still are not strait. whats going on with that? is it because they are made so cheaply?
i have an 02 gt with ThermaQuiet pads. i have been using them for about 6k now and i have braked very hard many times and still no vibration from my rotors. but after suck braking with my oem pads, i got alot of vibration. these pads squeek a few times when i first start driving, but after that they are silent. they also seem to stop a bit better. are these concidered race pads? oh ya, i have a life time warranty on these pads too

Another pad option is EBS green pads. I just installed them on my wife's car and they grip much better than oem pads.

my boss and i had heard this theory of no warping of the rotors so we tested it with a mic(measures rotor thickness) we got reading every 1/2" all the way around a warped rotor and came to the undeniable conclusion that the rotor was uniform in thickness all the way around...therefore this only leaves one solution...that rotors do warp. the idea seems plausible that you present...and sounds cool which is why people will jump on the bandwagon...but i'm holding to the evidence i have seen and tested...rotors can and do in fact warp.

Ok let me through in my .02.

Being in the auto parts bussiness for 17 years, I can tell ya'll a few things here.

1st. Rotors DO warp, you can heat up your brakes and drive through a water
puddle and WARP your rotors. And when you turn a rotor/drum(Ive done plenty over the years) it is not all pad/shoe deposits. And the newer composite rotors (1988 & up) warp alot easier than the older rotors/drums.

So always get your rotors/drums turned when doing a brake job!

2nd. As for a good quality pad, stay away from autozone. (unless you like brake dust)
I would reccomend either Wagner thermo-quiet pads or Raybestos super-stop pads. Look to spend at least $40.00 on quality pads.


And to the guy that says rotors/drums don't warp, Do you replace your rotors/drums at every brake job?
BTW I have pulled rotors off the shelf that were warped because they were stacked wrong. (not flat)

If you can't trust your partsman, who can you trust?

I have Performance Friction's Carbon Metallic pads and I can feel the extra stopping power over stock pads. I never tried Hawk, but I'll probably try those next.

Man wtf.... I dont know who to believe because my 3 year experience in the auto field tells me they do warp, now they don't, then they do...ugh I am going with what i see day in and day out until something more than a website can prove it. I have 20+ year senior master techs telling me they can warp due to conditions.