Hey All,

I have a 1985 F150 that I have completely replaced the brake system front to back.I have a baffling problem. Over a month or so, the front reservoir on the master cylinder goes dry and I lose about 50% of my brakes. Each time this happens, I trace all lines to each wheel only to find there has been no leak anywhere. I have replaced the master cylinder twice, including bleeding before installation, and bled each wheel. The problem persists. I know this supplies the rear wheels, but there is no sign of leaks anywhere and therear slavecylinders work fine once bled. Any clue as to what is happening?

 

Pulled both rear wheels and check the wheel cylinder cups for leaking? Run the brake lines and no sign of dampness? Checked the splitter at the rear diff and it's ok? Someone drinking your fluid?[sm=alien.gif]

 

if the rear slave cylinders were leaking, wouldn't they drip down onto the wheels? The junction is fine (without leaks)above the rear differential. No leakage from the brake lines that I can find.

 

They should, but if you don't see fluid anywhere else, then I'd put and eyeball on it. [sm=mail.gif]