Since learning all this, I have eliminated all brake shimmy in my personal fleet by doing the following:Ĭhecking all rotor widths with a micrometer, and all installs with a dial caliper for runout. This puts a "pad imprint" on one part of the rotor, that will continue to catch more pad material and build up. Typically this involves heating the brakes up, then coming to a hard stop and leaving the brakes on hard. Rotors were of uneven thickness when new. What's more there is lubricant on the pad ears, pad backs, caliper pins, etc., that happily allow movement on a new brake job (hopefully), but this lubricant gets washed off over time. It takes time for the pads to wear a bit and the friction materal build-up to occur. Why does it build up unevenly? There are three major reasons. However when it happens unevenly, it produces a shaking or shimmy feeling. This transfer from pad to rotor is supposed to happen, indeed it makes the brakes work better, which is why brakes function better after break-in. The shimmy feeling that comes from brakes is usually due to uneven friction material build-up on the rotor. What is passed off as a "warped rotor", and blamed on the user running through a puddle after heating the brakes, is a myth. Does this sound logical or far fetched? Help!!!! They are over heating and causing the rotors to warp. So the mechanic I figure has been putting on cheap parts. Got a third opinion today: rotors warped! This guy today says unmatched rotors and cheap brake pads. He checked the brakes hoses and says no leaks or problems there. He checked the calipers and they are not sticking. We had them checked again by the mechanic who did the back brake job thinking once again it could be the back brakes. So we went back to the first mechanic who did the front brake job. Took it back to the mechanic who replaced the back brake work thinking they may need adjusted, but it wasn't that. Once all that was taken care of, the car started to shimmy again when applying the brakes. He found the back shoes were worn thin, the drums needed to be replaced as well as the wheel cylinders. We kept experiencing problems with the back brakes and decided to take it to another mechanic. The mechanic we were going to said nothing was wrong with the back brakes, but to just keep driving the car. We have replaced the rotors 3 times, but prior to doing that we were having problems with our back brakes.
0 Comments
Leave a Reply. |