Brake troubles
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Joined: Aug 2005
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Brake troubles
I can't figure it out, it is a 1992 f350, the brake pedal will slowly go all the way to the floor with the engine running and pressure on the foot pedal. When the engine is not running it is hard as a rock and does not loose pressure.
I have replaced the master cylinder (twice, first a rebuild then a new one)
I have bleed the brakes the rear ABS valve the master cylinder, I have rebuilt
the front calipers there are no signs of leaks. The only thing that is left to replace is the Rear ABS valve, the ABS sensor in the rear end, and the power brake booster. I replaced the Intergral proportioning valve on the master cylinder although it does not look like the same valve that is in my manual, but it was the only valve for the master cylinder the dealer could find.
I have replaced the master cylinder (twice, first a rebuild then a new one)
I have bleed the brakes the rear ABS valve the master cylinder, I have rebuilt
the front calipers there are no signs of leaks. The only thing that is left to replace is the Rear ABS valve, the ABS sensor in the rear end, and the power brake booster. I replaced the Intergral proportioning valve on the master cylinder although it does not look like the same valve that is in my manual, but it was the only valve for the master cylinder the dealer could find.
Fleet Mechanic
Joined: Nov 2003
Posts: 1,372
Likes: 14
From: West Cornwall, CT
If you have a high hard pedal with the engine off, the master is OK.
Since the pedal drops with the engine running, it sounds as if there is a vacuum leak in the lines leading to the booster or the booster itself is bad.
Lou Braun
Since the pedal drops with the engine running, it sounds as if there is a vacuum leak in the lines leading to the booster or the booster itself is bad.
Lou Braun
