Residual pressure?

Hi, yesterday I had the drums off for an inspection and clean. Long story short, there was some residual pressure in the system enough to very slowly ,a mm in 2 minutes, extend the off side wheel cylinder once the shoe return springs were removed? Could this be related to the caliper sliders at the front still needing an overhaul as one side while free is not totally smooth and is waiting for the repair kit to be fitted? Any ideas?

I wouldn't have thought so. The fluid would just return back to the master cylinder reservoir with that pressure, just like if you had pushed the pistons of the cylinder back in yourself.

It's as if you have a one way valve keeping the pressure in that part of the system. I've heard of rubber brake lines breaking down inside and creating this situation but do you run rubber or braided brake lines?

Kirkynut

Rubber at the moment

I wonder if the rubber pipe on that side is damaged internally then?

I think Martin may have been the one to highlight the issue on here but I might be wrong on that. I've read it several times though and think once was in car mechanics magazine and possibly old Ed China mentioned it on Wheeler Dealers!

Using pipe clamps causes the pipe to split inside and the split part presses against the outside of the pipe acting like a one way valve.

It might not be this but a new pipe is how much? A tenner?

Kirkynut

There is a spring between the pistons in the rear cylinders that keeps the pistons touching the brake shoes, so the pistons will move out slowly on their own, presumably one is slightly stiffer than the other.

Nothing is broken

Awesome. Never had one like that. Cheers.