Rear Brake Intermittent Loss of Pressure

[beardyweirdy@me.com_imp]

Hi All,

I've got a puzzling issue with the rear brake.

I changed the pads a while back, and replaced the fluid.

All was good for a while, then I started to loose pressure.
It went completely so, I drained the system, stripped the master Cyl., checked it over, all looked good, cleaned and rebuilt.

Good pressure after re-buld but after a short while I totally lost all pressure. Nothing.... then it came back... then it went again!

I resolved to replace all the seals in the master Cyl.
But now it's working again, with good pressure, after doing nothing but letting the bike sit around.

Just wondered if anyone had any experience like this.

I'm guessing a replacement of the seals might do it, but wondered if it could be anything to do with the ABS?

Any ideas appreciated...

thanks
Kev