Soft/no brake pedal when running and soft pedal after first inch with car off.

[Jordan_J]

I have a hydroboosted car and was building boost when I heard a fairly loud pop/crunch like sound and the very instant that happened the pedal sank to the floor. My car barely stopped with the pedal all the way down at that point.

When the car is off the pedal is very firm, but if I press hard enough, after about an inch I feel what seems like a "bump" in the pedal and it goes straight to the floor very easily. When the car is running, it just easily goes to the floor and the pedal returns slowly.

I don't see any leaks in the lines anywhere.

I know the slow pedal can be a symptom of faulty hydroboost.

Would this be a bad master cylinder? Booster? Something else? Friends have suggested both MC and Booster but don't want to start swapping parts if I don't have to! Thanks fellas!

 

[charlief1]

Pull the master off and take a look where the 2 of them go together. There may be some fluid where it goes together and you should be able to tell which it is. Brake or steering fluid. Also check under the dash and see if it's wet thee. That should give you some idea.