'90 535i Caliper or Bearing problem

[hlenoble]

My '90 535i does not roll freely all the time. Most of the time I can feel a distinct "holding back." I noticed that my left front wheel is noticably warmer than the other 3 wheels after driving. I thought that the problem was on the left, and now it seems clear that the left front wheel is the problem.

My initial suspicion is that the caliper is hanging up, but is it possible that there is a wheel bearing problem? What can I do to definitively diagnose the problem? I am replacing the front suspension this week, so I am pulling the wheels anyway, making now a good time to do the repair.

Thanks in advance...

- Hal

[Jr ///M5]

Drive the car to get the caliper to drag or seize, take it back home. Immediately, jack the car up on that side and try to turn the wheel while it's off the ground. If it doesn't turn freely, pull the wheel off quickly. With the wheel off, crack the bleeder for the caliper to relieve pressure. If the hub spins freely, it's your brake line swelling or master cylinder binding, not allowing the fluid to return. If it doesn't spin freely, it's your caliper binding. Your caliper can bind up if the guide pins are crusty or the internal seals are binding on the piston not allowing it to return to normal position after braking.
I had the same problem with the 535 and the Mercedes, turned out the calipers were binding on the 535 and the master cylinder was binding on the Mercedes. This is the exact reason brake fluid is flushed on these cars on a regular basis. In both cases the previous owner didn't have it done as they should.

Hope this helps,
Jr