Rear brakes locking up

[ACLR8R]

I had installed a set of s-10 wheel cylinders and they were fine for the first couple of drives, but then they started locking up bad. So I just went ahead and put the right cylinders in, and the same thing is happening again. It is like once the self adjusters adjust them they start locking up. Any ideas?
Thanks

 

[MaxVO2]

Check to see if the proportioning valve under the drivers side door area is working by having somone press the brakes hard, and see if the exposed nipply looking thing moves. If you don't have the newer brass proportioning recall valve installed, you'rs may have gone bad.

You can check for more info on www.Gnttype.org in the technical articles section for more specific information on how they work, etc..

Hope this helps

Billy