PDA

View Full Version : Warpage?



Alexlind123
04-12-2006, 08:35 PM
I suspect that one or more of my brake rotors may be warped. The brakes shudder upon application, increasing in intensity as the brakes heat up. The front rotors have about 3000miles on them, and look brand new. No grooving or lippage or cracking, smooth to the touch. I replaced the front pads not too long ago as well. The rear rotors have some grooving, but no excessive lip or cracking. The rear pads have plenty of thickness left.

How can i check for warpage? Do i need a dial indicator, if so, where do i get one?

Rob
04-13-2006, 01:02 AM
It may not be related to rotor or brakes at all. Whatr speed does this happen at, or is it any time brake are on?

sKilled
04-13-2006, 02:56 AM
I had a similar problem - and I found the culprit whilst changing my discs. During the last pad change (last time I let ANYONE go to a 'pro'), the front left caliper was installed incorrectly. They managed to push out one of the rubber boots that guide the caliper out of the housing. I had a hell of a time getting it back in and I think I tore it...looking for a new one now:(

632 Regal
04-13-2006, 05:34 AM
thrust arm bushings? When do you feel the vibration?

Alexlind123
04-13-2006, 06:22 AM
I installed new 750il thrust arm bushing in september, and i only drove like ~40 miles a day. As i said before, the shudder occurs only upon application of the brakes. This is at any speed and does not occur when not braking. At low speeds like 25 in town, it is not noticable.

Rob
04-13-2006, 06:29 AM
Might be the brake discs. But still take Jeff's advice. Re check all front suspension parts that may be worn.

632 Regal
04-13-2006, 07:11 AM
http://www.bmaparts.com/epcvsoapimc.epc?cookieID=1S10OAWYM1S10OB3H8&drillid=8&subcatid=801030@@Front+Discs+%26+Drums&clientid=bmaparts

SchnellE34
04-13-2006, 07:56 AM
I suspect that one or more of my brake rotors may be warped. The brakes shudder upon application, increasing in intensity as the brakes heat up. The front rotors have about 3000miles on them, and look brand new. No grooving or lippage or cracking, smooth to the touch. I replaced the front pads not too long ago as well. The rear rotors have some grooving, but no excessive lip or cracking. The rear pads have plenty of thickness left.

How can i check for warpage? Do i need a dial indicator, if so, where do i get one?

I have exactly the same problem. I checked all suspension arms and bushings, everything checks out with very little play (or movement.) The pads look fine, very smooth and not worn past half way.

I have new Brembo's I am going to install and of course clean as much rust as I can off the hub.

Bill R.
04-13-2006, 08:12 AM
a brake rotor micrometer. When the wheel is off the car you have to use washers on the original wheel bolts so that you can bolt the brake disc down evenly then mount your indicator and check runout. Then you need to take a brake disc micrometer and check at at least 8 points around the rotor the check for variations in thickness. Either runout or variations will cause your problem. An indicator can be purchased cheaply through harbor freight tools. .0005 minimum is nice to have. And a magnetic base kit for it also. I think that harbor freight also has brake rotor micrometers too.. but by the time you buy this stuff you just bought a pair of rotors and then some.



I suspect that one or more of my brake rotors may be warped. The brakes shudder upon application, increasing in intensity as the brakes heat up. The front rotors have about 3000miles on them, and look brand new. No grooving or lippage or cracking, smooth to the touch. I replaced the front pads not too long ago as well. The rear rotors have some grooving, but no excessive lip or cracking. The rear pads have plenty of thickness left.

How can i check for warpage? Do i need a dial indicator, if so, where do i get one?

Qube
04-13-2006, 08:28 AM
If it shudders when braking at ANY speed, I would presume the rotors. If it only happens when braking firmer at higher speeds, I would suspect suspension components...

BillionPa
04-15-2006, 11:08 PM
I would suspect rust on the wheel hub causing a bad seating of the rotor, that can cause a LOT of problems.