1994 Ford F350 Two Wheel Drive Automatic 90000 miles
I have a f350 dually diesel. The brake pedal goes to floor when engin is running. Ok when motor is off. New master cylinder, bench bled, no leaks in system. Full system bled three times, all brakes adjusted and in good condition. The shop I had the work done at has no idea.
Was pedal going down the original problem? If yes problem in Hydro-boost accumulator leaking down.
Pedal go down slow when pressure applied? Do brakes apply?
Let me know
Thanks for donate
June, 22, 2010 AT 12:54 PM
Yes the pedal went down in the begining. They started with the master cylinder. The brakes apply when depressed and pedal slowly goes to floor
June, 22, 2010 AT 1:23 PM
On my brake system I have a vacumn booster behind the master cylinder so I don't think I have a hydro booster accumulator
June, 22, 2010 AT 1:50 PM
Thought it was superduty many 350 are so try this apply parking brake not full on but say 5 clicks does pedal not fall or go slower?
June, 22, 2010 AT 2:00 PM
With parking brake on half way does not make a differents still creeps to the floor when pedal is applyed
June, 22, 2010 AT 2:19 PM
Checking break pedal reserve engine idling pump pedal 3-4 times the off pedal wait 15 sec. Now apply brake pedal untill it stops. Now raise engine RPMS to 2000 then release accelerator as engine returns to idle brake pedal should move downward. If not check vacuum pump
June, 22, 2010 AT 2:41 PM
The problem is when you wait the 15 sec. Then reply pressure it dosen't stop it just goes slowly to the floor
June, 22, 2010 AT 2:58 PM
This my last idea was the porportioning valve on the new master cylinder or reused from old one?