ive got a very confusing problem with a van ive been working on, its a 2003 dodge minivan, have replaced the rear brakes and wheel cylinders, bled brakes and a few days later there was a massive leak inthe system, pulled apart the brakes and discovered the wheel cylinder on the passenger side had pushed the piston out of the bore fully on the side facing the front of the van. it shouldnt be possible for it to over-extend and "blow up" but it did. thought maybe there was a spring problem as one was floating around in the drum. put a new spring kit in, checked everything, re-bled brakes and put it back out on the road again. have heard the brake light is back on again and i will be looking at it again tommarrow. dont know why it could be happening, looks like all shoes are identical, no "primary" or "secondary" specific shoe. measured the wheel cylinders and all seem to be the same length. drums were not turned, just knocked the rust-ridge off with a dremel tool. how on eart could the wheel cyl expand far enough to push out a piston and lose fluid? and only on one side? it defies all logic for me. whats worse is that its not even my vehicle and i have no idea how to explain this. you would think it would have happened right away, not a few days after the fact. any ideas?

 

I assume you are adjusting the brakes correctly,if they are not adjusted,then the wheel cyl. will try to take up that space when the brake pedal is pressed,also check the drums and make sure they are in spec.

 

Sounds to me like either a brake shoe wasn't on that wheel cylnder completely and came off when the brakes were used and blew the piston out. Or wrong parts, or not adjusted enough.
Bob