Front Calipers Sticking

[askiles]

So I am having a bit of a problem with my front disc brakes. After some use, the pedal gets more and more stiff, and then is stuck near the top of my travel, meaning the calipers are stuck closed. The wheels will not turn at all. I can open the bleeder and it lets off the pressure, and then it is good...until the brakes are pumped about 10 times. Each time it gets more and more stiff. What would be causing my brakes to do this?? I have driven the car for awhile now, and it just started to do this. They are early GM calipers, early GM master cylinder, and a 2lb residual valve I believe. Is this a bad residual valve?? Any and all help is greatly appreciated!!

 

[James C]

Sounds like a bad valve to me

 

[askiles]

Thanks. That was my thought. Basically it is stuck and performing as a check valve, not letting fluid back into the master cylinder.

 

[Golly]

Make sure the brake pedal is returning all the way back. Sometimes it will stick on the floor , or carpet etc. and not completely return, thus, uncover the return port in the master cylinder. (personal experience)

 

[RPM]

Sounds like you have the push rod for the master cyl adjusted to tight. It should have no slack in it, but not tight enough to have any preload on it.

 

[2old2fast]

Got a return spring on the pedal ?
dave

 

[409T]

Check what RPM said.

 

[Swampdog]

I've seen sticking calipers caused by the flex line going bad and the internal line collapsing and holding the fluid from returning to the master cylinder. Sort of like pulling your arm out of your coat and the lining coming out with it.

 

[railroad]

Usually just one line on fronts.