So I bought this car a few days ago, and brought it back to the lot to get the 'due bill' items corrected. One of those items was the 'shudder' (warped rotors.) They sent them off and had them turned, and remounted.

Now I'm getting a pulsating rub noise I can hear distictly from the front end. It did correct the original shudder and the brakes are very smooth and exact. My first panic was one of my wheels was mounted wrong and it was clipping a caliper, which doesn't seem to be the case.

I've done lots of brake jobs myself, and even rebuilt a couple of calipers... Brakes a pretty basic mechanical instrument (minus the new fangled computer assisted junk).

Anyone run into this after a simple R&R w/ resurface? My initial thought was the pads needed to rewear into the rotor (the pads are at about 60%).

I'm gonna take it back tomorrow and have them stick it on the lift. Thoughts beyond that? Anything I should look for?

Thanks!
-M

 

I got this resolved today.

It boiled down to an error when remounting the passenger side front caliper. It was slightly cocked and the inner edge of the rotor was rubbing against it. The rub was very minor and the rotor nor the caliper appear to be damaged.

It's a lame mistake, and mercifully a minor one. *sigh. Oh well.. thing stops on a dime smooth as silk!

-M

 

It really sucks when service shops and pro mechanics screw things up or don't perform quality checks. This more than any other reason is why I do all my own work.

Generally you don't resurface German disks. They can warp for various reasons, and turning them usually doesn't get rid of the warp permanently, as the stresses in the metal that caused the warp carry through the disk, not just on the surface.

Best practice is to simply replace the rotors when warped or too thin when mic'd. (That is why German discs are so dam cheap when compared to Japanese or American discs). Most brake jobs should only replace the pads, scrub the old discs with a green scrubby and brake cleaner, then bed the new pads in real well.