I have a 1995 Ford F-350 with RABS II braking system, on which I recently replaced the front rotors, calipers, pads and rear drums, shoes, wheel cyls,& hardware.
I purchased a Motive power pressure bleeder and have bled both front and rear a number of times including the hydraulic control unit on the left side frame member, only to come up with the same result of a soft brake pedal when the engine is running. The brakes work well but the pedal sinks and is soft.
With the engine not running the brake pedal is real firm as it should be. I disconnected the electrical connection to the ABS on the Hydraulic control unit and I got the ABS light on the dash, reconnected the wires and the light went out so it seems as the ABS is working. The brakes worked well before I worked on them, but they were well worn. Since I am new at using the MOTIVE bleeder I intend on bleeding them again, it seemed to work as it should, I have clear clean fluid at all bleeder screws. Any suggestions??
Thanks, Jim

 

 

I read about removing the spring on the modulator...think I'll give it a try along with a manual bleed. Thanks Hayapower.