B-body brake question?

I need help with brake question. I'm having problem with rear brakes sticking on my car.(everything is new) except poportioning valve and hold off block?(I think thats close to its name) but anyway I can break loose either bleeder on whl cyl and you can hear both sides let loose and as soon as you hit the brakes again pow locked up again, Have vacuumed bled and still locking up. What does the hold off block do? Please help......

I'd check the rubber line going to the tee on the rearend. They can deteriorate from the inside out.

Manual brakes?

How much free play at the pedal?

Sorry I missed the "everything is new" part.

After the brakes lock up remove the bolts that hold the master to the booster or the firewall. Do the brakes release?

Sorry it's pwr disc and rear drum, and all hoses are new. I even replaced the tee with another. How do you measure free play?

Allen, I'll go try it real quick, i'll be right back

I'm suspecting the rod in the master is not fully retracting. This will not allow the fluid to return to the reservior.

I had a similar problem with mine (except it was the front wheels that were locking up) Ended up being the MC. Swapped it out with another that I had and I was good to go.

I just loosend the MC and it did not release pressure. The MC is new(Napa) maybe got a bad one?

If you lossen the fitting at the master for the rear line and the brakes release now, I would suspect it to be a bad master. Of course if the rear brakes are still locked up after doing this, I would suspect it to be something else.

I also tried to do a reverse bleed by pushing fluid through system by attaching to one of the rear cyl bleeder and when i opended and tried to push fluid through it would not go through but felt like alot of back pressure when i was trying to push it through. Should i remove MC and make sure rod is not jammed??

You loosen (removed) the master nuts holding the master to the booster. This should release the interference if there is any.

So what happen when you lossen the fitting at the master for the rear brakes? You will have to a least hand thread the nuts so the master won't move when you break the line free.

Allen,
I might have found it, The MC line i loosend and nothing. So i moved to the first thing moving from rear to front which is the hold off valve loosend line on the front side MC side nothing move to back side and wham brakes released..So it looks like it can be taken apart from bottom?? Can it be taken apart and cleaned?

I have never done it, but I've heard that you can do it.

me either, maybe it's just like poporotioning valve? Spring and ball?? Not sure but after supper I'm going to go pull it apart and see what it consists of.

Allen,
I removed the block tried taking it apart (decided not to) anyway cleaned it out. It's like a pressure type valve anyway after cleaning and re-installing it. It started car back up and forward and NO locking rear, Knock on wood I think it might be fixed. I got to take it for a alignment tommorrow so i'll but it to the real test, Thanks to everyone for their Input.