nubomb

Just had my brakes done, all new rotors and pads and new fluid. The car stops fine (better then before), no squeeling but at low speeds when I'm breaking to a stop it feels like something is warped or my rims feel terribly out of balance. Car brakes pretty straight, not a lot of travel or vibration in the pedal. Any idea on what is going on? I didn't think a brake job could get hosed so I'm wondering if I'm out of balance somewhere. Curious as to what it could be before I bring it back to the mechanic.

lars

You'd suspect, from the timing, it would be something to do with the brakes. You don't say if you have one of the cars with brake-by-wire, which probably wouldn't provide that kind of feedback through the pedal. If the vibration isn't in the brakes, one thing that could cause a low-speed wobble is a broken tire belt. I had one of those once. It took me a long time to find the problem, which is why I mention it, and several trips to different tire balancers. I looked for runout, all the other possible causes and in the end decided to replace the tires. 'Oh", said the service guy as he took the tire off, "look, you have a broken belt". Look for a dimple in the tire wall.

Diamond White W212

Did you properly bed in the brakes?

Here is are two EXCELLENT articles from StopTech and Zeckhausen Racing on bedding in brakes. More importantly, it explains what causes that 'warped' feeling, even though the rotors themselves are not warped;;

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

http://www.zeckhausen.com/bedding_in_brakes.htm

It takes awhile to read but I think it will answer your question well.

mleskovar

+1 Also...if during the break in process you need to come to a stop and hold it use the parking brake. The object is not to transfer/exhange material between the pad and rotor during break in.

nubomb

Thanks all for the feedback. My car is a 99 CLK430, so I don't think it is break by wire.

I guess I have a couple of things to check on. I do have a bulge/bubble in one of my front tires so that may be causing part of the problem.

Could it be due to over tighting or not a consistent fit on the lugs on the rims as well?

Since these are OEM brakes and not reall high performance stuff I didn't think there was any real proper brake in procedure. I'm guessing I can still do this and hopefully burn off any material imprints?

mleskovar

Makes no difference who made the pads, break in is important. Improper break in can also cause the common squeeling everyone complains about. Often you can just look at the rotor and see an imprint of the pads when it's done wrong. Try 120 wet/dry sandpaper on a rubber block and cross hatch both sides of the rotors....then do the break in procedure.

Htowncls

good post OKClass.. it helped me out today putting on the porterfields on the front and bedding..

vettdvr

[QUOTE=nubomb;2094706] I do have a bulge/bubble in one of my front tires so that may be causing part of the problem.

Could it be due to over tighting or not a consistent fit on the lugs on the rims as well?

QUOTE]


If you have a bubble/bulge I would change the tire immediately. It could blow out and cause serious damage to the car and you in an accident.

Also if the lugs were not tightened properly you could have warp in a rotor. Final comment the mounting flange where the rotor mounts should have been cleaned at installation to insure running true also. Jim