Hi I have a 1993 F350 4WD 7.3L and Iam having problems with my new brakes
I have replaced the front rotors, pads and calipers also the rear drums and shoes also the wheel cylinders and I have also replaced the power booster and master cylinder well this is the third master cylinder and I replaced the vacuum pump. The problem I am having is every time you step on the brake it will kind of stop the truck but then the peddle will fade to the floor I have bleed the brakes
over and over also put a power bleeder on it Iam getting all fluid no air. If the truck is off the brake pedal is fine but like I said when it is running the pedal fades to the floor.Also Iam not losing any fluid out of the master(like a line leaking).I cant fix the problem so I hope someone can help.

Thanks
Jeff

 

This isn't going to help much. I've been through the samething. The truck stopped just fine, but holding pressure on the brake pedal, it would keep going donw. And I reaplced about everything that I could change, and was told by one of the "Older Guy's" that it's "The Nature of the beast" that it was the system that was in the truck.

 

This might not help much either. My truck did the same thing, and I replaced
everything too. Mine ended up being the vacuum hose was cracked, running
to the vacuum booster

 

If your resevoir is seperate from the actual master (plastic),check for air leaks around the grommets.I've seen them suck air there,but not lose any fluid.