84 4KSQ - Need advice on brake problem

[Huw Powell]

> Replaced master cylinder, bled cylinder and brakes again...worked fine for a
> while....then, had to put the brakes to get a high hard pedal....bled brakes
> yet again...air in the line and frothy fluid....Done this 2 times and still
> poor brakes...no signs anywhere of leakage or fluid loss.  Mechanic says
> there is what he believes there is a proportioning valve under the master
> cylinder.

Yes, there is, and it has to be bled too.  Your symptoms do sound rather
like the air is never being properly evacuated from the system.

The bleed order is, as I recall, prop. valve, RR, LR, RF, LF, prop valve
again.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/