Ok I have a 86 3/4 ton 4X4. The brakes will stop the truck but the pedal goes to the floor. I replaced front and rear brakes and the master cylender. What else could be the problem? I thought maybe the soft lines are swelling under pressure so I have some new braided lines on order. I know the brakes aren't famous for their quality but at least the peddal shouldn't go to the floor. I have also blead them a few times. Could it be that hieght sencing valve? Are there any cons to just removing that and having full pressure at all times?