Brake pressure when truck is off, but once it is started the pedal goes straight to the floor. What could be the problem? We had originally thought it was the mast cylinder, and bled and replaced it. We also bled the brakes after word. Then we realized there was a busted brake line and we replaced that and then re-bled the brakes and kept fluid in the master cylinder reservoir. There is brake pressure when the truck is off, but once the truck is started I lose all brake pressure and the pedal goes straight to the floor.
Saturday, October 1st, 2011 AT 6:17 PM