After swapping in 3/4 ton axles, I still can't get my brakes to work. Through all my trials I have: swapped out the master cylinder(new), proportionong valve, & booster with stuff for the 3/4 ton truck I got the axles from. I know there's no leaks in the system, but I can't get them to bleed correctly. I get good pedal while I am bleeding them, but as soon as I start it up it goes to the floor. The other thing that is happening is: After pumping up the brakes & bleeding them, I open the top of the master cylinder & fluid shoots out on the half thet goes to the front brakes. Is that part of the problem? If so, what causes it? My next step is to replace the wheel cyl's & calipers so that everything is new. I don't think that's gonna solve my problem, but at least everything will be new.