My Buddy has a 1994 F350 5.8L, runs great but wont stop when you try to brake. We've replaced the booster and master cyl but the pedal still sinks straight to the floor barely able to stop the truck. Any ideas on what it could be? We're thinking something with vacuum pressure...

 

im gonna assume you went around a bled all the lines right?? keep bleeding them.. it might take a few times around. i replaced a the rear lines on my old 97 and it took 3 times around to get all the air out.

 

We did do it once and We are gonna do it again tommorrow. And then check all the hoses and lines for leaks. Thanks for the response.

 

You do know that you need to bench bleed the master right? If not you'll never purge the air. You can't just slap on the MC dry and expect it to work.

 

We did the bench bleed of the Master Cylinder and we bleed all the brakes a few times, and the pedal still goes straight to the floor. We are completely baffled right now.

 

theres air somewhere just going to take some time to get it out

 

sounds like a leak or air still..ive done some brakes that i had to bleed them for about 30 minutes before they finally worked. did you adjust the rod?