Anyone having a problem with brakes jamming on 1089 928? Any suggestions on what the possible causes could be? Could it be the master cylinder or booster?

 

Have you pulled the wheels and inspected the calipers, pads and rotors??????? What do they look like? How many miles on the car? when were the brakes done last?

 

Brake master cylinder is most likely culprit, BTDT.

 

Is it just one caliper or all four?

All four would tend to make me think it is a bad master cylinder. Put new brake fluid in the system first, if the problem continues, replace the master cylinder.

If it's just one wheel locking up, then I would rebuild the bad caliper and bleed the system.

 

Was about to edit my post after Gretch's response... if all 4, MC.

 

if you find a caliper sticking ( IE by doing the test the rotor with the IR gun ) make sure to rebuild both calipers for that axle. Make sure the push rod is adjusted correctly as if its not retracting then the master will hold pressure i9n the lines then its only a matter of time till thiungs get hot.
So what was the last thing that you fixed???

 

I had a single wheel lock up problem on an '85 S (right rear). Turned out that the brake cylinder was scored and the brake piston was hanging up on it... Worth checking.