I have a 1995 4x4 with 5.9 motor automatic. I have replaced all working components that have to do with brakes, bled the brakes. When I put my truck in reverse and turn the wheel to back out of a spot the brakes sink to the floor. When I put it back in drive if I pump it once it catches and will never sink to the floor again as long I am driving around, it only does it if I am in reverse turning, no other time.........anyone have any ideas what it wrong??? Parts I have replaced are master cylinder, calipers, shoes & front pads. Back wheel cylinders are both functioning and not leaking. I have been told to drive it and accelerate and slam on my brakes to adjust them and that has not worked either.

Thanks,
Tony

 

Just bumping to see if anyone can help me!!

 

Since everything works fine when moving forward, I'd say everything at the wheels is installed correctly. No vacuum would make for a hard pedal. Too much vacuum would make for a soft pedal. What do your RPMs do when you put it in Reverse and turn the wheel?

 

Thanks for the reply, RPMs are at normal while backing up this was also something I considered. Someone today I spoke to thought it might be the brake booster any thoughts on that?

 

But it works fine moving forward so the booster is holding or working properly then. The brakes are going to the floor based on you switching into Reverse and turning the wheel. They are only going to go to the floor if there's too much boost or you have a leak somewhere. You said everything is dry and it works fine moving forward and you're not out of brake fluid yet so, you shouldn't have a leak. I can't think of what this would be. Sounds very odd. I don't think you can install your lines wrong when you put a new master in. Did you connect all of the electrical connections good? Might double check those again.