Hot Rear Brakes

[PakProtector]

Well I can confirm that now the right rear is dragging and the left rear spins free.

So given it switches sides, something is stopping it from pulling back far enough. Still lost as to exactly what. My Benz did this and I had to adjust the booster pushing spike.

Douglas

 

[JDSwan87]

Just did the VCDS ABS actuation and now BOTH rear brakes are heavily dragging after 10min of waiting for them to release. Changing the master cylinder (since I already have it).

 

[JDSwan87]

Changed the master cylinder (it was already on order before oilhammer said it's not hydaulic), problem remained.

I took the pads to work today and removed .030" from the steel backer where the pad rides in the carrier clip (NOT where the piston contacts the steel backer). Pads move free-er now, not that it was bad before... Reassembled and the problem persists.

As mentioned earlier, it appears the problem is switching from side to side.

 

[jmodge]

In the picture where your parking brake cables attach up at the handle end it looks like you have two different lengths cables, something appears off anyway. Did you ever disconnect them from the calipers and drive it?

 

[JDSwan87]

In the picture where your parking brake cables attach up at the handle end it looks like you have two different lengths cables, something appears off anyway. Did you ever disconnect them from the calipers and drive it?

E brake cables have since been disconnected at the caliper for troubleshooting.

Anyone know what "normal" operating temp for MKIV rear brakes is? I'm in the 200-250*F range after a 4 mile drive, 50mph, stops every mile... (a decrease from 450*F)

 

[jmodge]

E brake cables have since been disconnected at the caliper for troubleshooting.

Anyone know what "normal" operating temp for MKIV rear brakes is? I'm in the 200-250*F range after a 4 mile drive, 50mph, stops every mile... (a decrease from 450*F)

They should be within 10-15 degrees of the fronts, all four should be within that perimeter

 

[snakeye]

Try another caliper that you know doesn't stick. I was almost in the exact same situation as you last summer: new TRW calipers and carriers, car with ESP, new MC, new booster, Akebono/Zimmerman combo, new HD cables, rear left brake line.... Rear left kept sticking. Put the old caliper back and it stopped right away. Since then the brakes haven't dragged.

One, and then the other handbrake lever on the calipers did however start sticking, but I kept manually reseting them, and eventually the problem fixed itself, and that's been fine since 3-4 months now. It's as if you need to break the rear brakes in or something. I did read on here at least once that the rear left brake is known to cause problems, not sure why.

 

[JDSwan87]

Well I drove the car to work today, 10 miles, stops about every mile. The "hot side" appears to have changed from the left rear to the right rear.
LR 175
RR 495
LF 275
RF 265

Thoughts

 

[jmodge]

The only temp that looks normal to me is the LR. I would crack a bleeder on any of those other 3, the rest are VERY hot. If I was in your shoes I would suspect something with the ABS and would cycle, bleed, and drive it multiple times checking temps for change and cracking bleeders. Looking for consistencies and inconsistencies, any kind of clue as to hydraulic or mechanical. At those temps you might have some new warpage added in to the picture