RANDY P

Needed.

Had a nasty problem with shimmy while under moderate braking. No steering wheel shake, body shake slight shake in car and gearshift quivering like it's excited.

Was pissing me off pretty bad. Pulled wheels off several days ago and pads looked good with even wear and rotors seemed to be wearing evenly.

Did a quick re-bedding of the pads by doing a series of 50 to 10 MPH hard stops (Almost triggering abs) without actually stopping, just slow down- about 10 times in a row and problem solved.

The problem seemed to be excessive brake material deposits causing high spots on the rotors...

I'm on standard semi-metallic pads and oem rotors BTW. If you get shimmy, pound the brakes with some hard panic stops and that should fix it.

Gspec

lol.......no

RANDY P

Really? Why don't you tell me why not?

24 HRS still fine BTW.

zhillz

This.

Its kind of hard to explain but your pads are going to contact in the place regardless of pressure. In theory you would have just made the low parts lower equivalent to the high parts making the high parts lower. Get it?

RANDY P

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

You don't always need to replace or turn the rotor. In my case, my rears had some deposits. I underlined the part in question. I don't drive the car on a track or abuse it and I am on semi-metallic pads. So, I opened it up and re-bedded everything.

My suggestion above was "try this first" before running for new rotors. That's all.

The obvious question now is "is there a "cure" for discs with uneven friction material deposits?" The answer is a conditional yes. If the vibration has just started, the chances are that the temperature has never reached the point where cementite begins to form. In this case, simply fitting a set of good "semi-metallic" pads and using them hard (after bedding) may well remove the deposits and restore the system to normal operation but with upgraded pads. If only a small amount of material has been transferred i.e. if the vibration is just starting, vigorous scrubbing with garnet paper may remove the deposit. As many deposits are not visible, scrub the entire friction surfaces thoroughly. Do not use regular sand paper or emery cloth as the aluminum oxide abrasive material will permeate the cast iron surface and make the condition worse. Do not bead blast or sand blast the discs for the same reason.

But of course, had I been some 80 y/o lady at the stealership or some hack shop their ""mechanic" would've told me to replace everything. That's the nature of most shops these days.

Just replace it.

rjp

PS: 48 hrs and 100 Miles, still fine.

zhillz

Now i understand.

RyanV

iTrader: (9)

Im going to try this because I had my TT front rotors turned and my brakes were perfectly smooth for a couple weeks. Now I'm getting vibration and I never really stomp on the brakes because I don't have to so I could believe a buildup of pad dust adhering to a hot rotor.

I'll try this tomorrow and see what happens and report back.