Truck has 79K original miles on it. The brakes were very spongey and the Hydroboost was wet around the accumulator. I bought a re manufactured Hydroboost from Napa. Switched it out and the brakes were not any better (I swapped out the push rod also per the directions also). I also bled the unit with the tires off the ground and side to side to purge the air. I noticed that the old master cylinder had some fluid getting past the lid so I figured I would just install a new one to see if that was part of the problem. I installed a re manufactured unit from Napa. Bench bleed, installed and tried to bleed the brakes. Now I have zero brake pressure. So I pull the new MS and take it back to Napa for a brand new one. I do the same thing and get it installed. Still, zero brake pressure. The brake pedel goes to the floor very easy (and returns slowly) but will not build pressure.
While bleeding the brakes, the rears would pull solid fluid from the vacuum so I know they were bled well. The fronts will just pull a combination of air and fluid. It will never get a solid stream of fluid. I have run a gallon of fluid and it keeps pulling air from the fronts only...
Since the new Hydroboost unit was not better than the original one, I am thinking that perhaps it wasn't a Hydroboost issue to begin with. I also had pressure with the new unit prior to swapping the two master cylinders. The chevy dealer by my house had no idea what it could have been. How am I pulling air from the front brakes. I even tried gravity bleeding with no luck and the old fashion buddy bleed. I am getting no pedel pressure whatsoever.
I do not see any leaks from the wheels or anywhere else for that matter.
While bleeding the brakes, the rears would pull solid fluid from the vacuum so I know they were bled well. The fronts will just pull a combination of air and fluid. It will never get a solid stream of fluid. I have run a gallon of fluid and it keeps pulling air from the fronts only...
Since the new Hydroboost unit was not better than the original one, I am thinking that perhaps it wasn't a Hydroboost issue to begin with. I also had pressure with the new unit prior to swapping the two master cylinders. The chevy dealer by my house had no idea what it could have been. How am I pulling air from the front brakes. I even tried gravity bleeding with no luck and the old fashion buddy bleed. I am getting no pedel pressure whatsoever.
I do not see any leaks from the wheels or anywhere else for that matter.