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95 F250 PSD (Brake booster has 500 mi. on it)...The brakes are working, but the pedal is REALLY soft. I think it is a vaccum leak, but I would love to see if anyone has any ideas on how to check and what to do if it is.
Yes the cruise works great and no the brake light is not on. Also I replaced the check valve @ the booster. The pedal will come back up after the brake is released, just not quite as fast as it should. The guy I bought it from said something about the actuator for the damper control under the dash @ the climate control??? I was going to pull each vaccum line from the tree and plug them one at a time to see if that will help, that way if one is bad I'll know which one and I can replace it. I am also going to bleed the brake system asap to see if that changes anything.
Last edited by Smokin&Strokin; Feb 10, 2008 at 10:20 PM.
Just wondering what would the cruise control have to do with it?
One of the inputs to the PCM module is the line going to the brake warning light. If this line is grounded, the cruse control is disabled.
If the warning light is burned out and one of the things that turns the light on is activated, then the only sign will be a non-functional cruse control.
Low fluid, the parking brake, or low vacuum can all trigger the lamp and disable cruise control.
Yep, a bad damper in the climate control could do it. The vacuum switch triggers at a real low vacuum - by the time the light comes on, the vacuum is way down.
But low vacuum will produce a hard pedal. Low/no vacuum=no power brakes. So can assure you that if your pedal is soft you do not have a vacuum issue. You either have a bad master cylinder, air in the system, moisture in the system, rear brakes out of adjustment, a leak, or a bad RABS valve.