Brake problem, rear brakes are locked up.

[broncomitch]

I recently replaced my prop valve and a few lines and plumbed in my cnc cutting brakes.

Afterwards my rear brakes are stuck on and won't release unless I Crack the bleeders...

First time I cracked the lines leading all the way back and the pressure never released unless I cracked the bleeders..

I figured my old rubber lines were swelled up not letting fluid return, so I replaced em with no luck, and I pushed the Pistons back in the calipers and they seem to move freely.

I cracked the inlet on the cutting brake and nothing, I cracked the outlet and the pressure released a little bit.

I'm going to bypass it tomorrow and see for sure but it doesn't make sense and the cutting brake works perfectly too.

 

[Spork]

Bad master cylinder maybe?

 

[sawtooth4x4]

I had that happen to a range rover. ended up being the master cylinder

 

[broncomitch]

I thought the same thing..But I can take the line off the master cylinder and the pressure dose not release..

 

[I Lean]

It sounds like from your diagnosis so far, it almost has to be the cutting brake. It is supposed to be in "bypass" mode until you move the handle, so your brakes work normally. Can you manipulate the lever and get them to release? (like the pistons aren't moved far enough to be in the open spot) Any adjustment possible on that?

 

[broncomitch]

I moved it back and forth and didn't notice it releasing pressure..but I do think there is a little adjustability in it.

 

[broncomitch]

The line up top (far left) is the inlet, the line to the right of it is the outlet.

 

[broncomitch]

Looks like I found the problem.. I think??
The inlet hole is drilled off center so the seal on the plunger is covering up the hole..

Inlet/top section.

inlet/bottom section.

plunger.

 

[broncomitch]

So apparently the problem was the keeper/adjuster was screwed in to tight..
The pressure pushes the piston forward to let the pressure through run back through...the adjuster wouldn't let the piston move forward.
All is good now apart from my peddle and cutter being to soft..