Brake Problems....
12-31-2014, 10:17 AM
#1
Brake Problems.... Sorry to ask this here but....you guys are generally the best source for information.
My wife's 2004 Yukon out of no where had the brake pedal go to the floor while she was driving it. The brakes worked, just not very well and not until the last 1/2 inch of pedal. I figured it was a master cylinder, so I just replaced that. Spent an hour bleeding it on the bench and am certain I got the air out of it. When I pump the brakes with the car OFF the pedal feels normal, I get resistance and it doesn't feel spongy. Turn the car on and the pedal goes right to the floor and returns very slowly. It does not have a vacuum booster, it has GMs hydro-boost that runs off the PS pump, which is working normal as I have power steering atm.
Any ideas? Any help would be much appreciated.
My wife's 2004 Yukon out of no where had the brake pedal go to the floor while she was driving it. The brakes worked, just not very well and not until the last 1/2 inch of pedal. I figured it was a master cylinder, so I just replaced that. Spent an hour bleeding it on the bench and am certain I got the air out of it. When I pump the brakes with the car OFF the pedal feels normal, I get resistance and it doesn't feel spongy. Turn the car on and the pedal goes right to the floor and returns very slowly. It does not have a vacuum booster, it has GMs hydro-boost that runs off the PS pump, which is working normal as I have power steering atm.
Any ideas? Any help would be much appreciated.
12-31-2014, 11:23 AM
#2
It's one of the factory soft lines. Have the car running so it has power boost, someone in the car to push down on the pedal. You will see one bluging most likely. When the car is off you don't have enough pressure to replicate the line failure.