57 fleetwood brake lock up

[Brad Janousek]

The brakes on this 57 cadillac are stuck about 1/2 on and they wont release.  All four wheels are locked.  The first time it did it they released after about a hour but when they locked up the second time they have been on all weekend.  I can move the car under power but it barely does it.  I verified all four wheels are locked each time and Im sure it has something to do with the master cylinder.  Ive never messed with hydroboost brakes and I thought I might get some opinions here before I dig in. My guess is the bleed hole in the MC is plugged?  Thanks for any help.  Brad

[wm Link]

My guess would be either all the drums have ample surface rust on them or pitting in the cylinder of the master cylinder since it is affecting all the wheels. You could loosten the brake line at the master to purge and retract the wheel cylinders.

[Paul Flykt CLC # 18899]

I had the same problem with my 57 before I had the booster rebuilt. The only way I could release the brakes was to unhook the vacuum line at the intake manifold. Then I tapped on the "tin can" portion of the booster that houses the piston that provides the boost to release it. Apparently the leather seal on the piston was hanging up and keeping the brakes applied.
I could drive the car with the vacuum line unhooked, but sure took at strong leg to stop it. I cut the hose and plugged it by the check valve at the manifold and drove home.

Paul

[Brad Janousek]

Thanks for the responses.  It was exactly as Paul stated.  The leather lined drum that runs in the tin can was hanging up.  I completely cleaned the booster and everything with it and it works great now.  Thanks, Brad