E-350 AMBULANCE BRAKE PEDAL FADE

1991 Ford E-Series Van

Tiny

McQueen Repair

November, 12, 2007 AT 11:39 PM

Replaced Master Cyl with NEW unit (I Avoid Reman Units as much as possible), Bled System, checked adjustment, Still had Pedal fade, Replaced Master With second New Unit.

With Engine running, pedal still slowly fades to floor. RABS light is on but no codes are stored.

30+ Years in the Biz, and I'm Stumped!?

FOUND 11 RELATED QUESTIONS

5 Answers

Tiny

fairracing31

November, 13, 2007 AT 12:11 AM

Good possibilty you have a frozen or sticking front calipar.

Tiny

McQueen Repair

November, 13, 2007 AT 12:23 AM

Calipers and Wheel Cylinders were first on inspection list, Calipers Collapsed easily, no leaks, slides are ok, wheel cyls. And rear shoes appear to have been replaced within last 6 mos.

Tiny

McQueen Repair

November, 13, 2007 AT 10:50 AM

Replaced Vacuum Booster, Now have proper Pedal Height, and NO FADE! : Mrgreen: : mrgreen: : mrgreen:

Tiny

fairracing31

November, 13, 2007 AT 11:09 AM

Wow, that is a new one on me. Never seen a brake booster cause pedal fade. How did you determine it was the brake booster?

Tiny

McQueen Repair

November, 13, 2007 AT 8:04 PM

I isolated the Master Cylinder (Installed plugs in line Fittings), Engine off, Vehicle had a solid pedal. When I started the engine, the pedal faded away. On the second test I stepped on the brake with the engine running. When the pedal reached the halfway point, I shut the engine off. The pedal stopped dropping. After 1 1/2 minutes of applying pressure, and no pedal fade, I concluded the booster must be bad.

Fortunately, I was right. I've been repairing cars for 30+ years and have never seen a booster fail in this way - a good Tech is always learning!

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