Outer Limits 4x4 Board

I have a 93 Sierra.
Replace the rear shoes quite often as I drive a fair amount of mud.
When the brakes start to get reaosnably low the passenger side wheel cylinder pops the piston out and I lose all my fluid
Any suggestions as to why its doing this?
My understanding is that even if my rear brakes were metal to metal the piston should not be popping out?

Cheers PAUL..

mistaboz wrote:I have a 93 Sierra.
Replace the rear shoes quite often as I drive a fair amount of mud.
When the brakes start to get reaosnably low the passenger side wheel cylinder pops the piston out and I lose all my fluid
Any suggestions as to why its doing this?
My understanding is that even if my rear brakes were metal to metal the piston should not be popping out?

Cheers PAUL..

There are more than 1 type of rear cylinders fitted, you may have wrong one. If too narrow, they will pop out at end of shoe life.

Maybe you are missing a spring, retainer or similar, or have stretched one too much. Just guessing here, have no idea..discs rock

could be the drum has been over machined to a point where shoes can open too far???