Ok, truck seems to stop fine, pedal feedback seems normal but... I was holding the truck and trailer (with the brakes) on a hill. I could feel a very slow give to the pedal under my foot. If I kept applying force, the pedal would slowly drop to the floor after 2 to 3 minutes. The pedal returns to normal if you release it from the floor and apply the brakes again.

My logic tells me that there is a leak somewhere but I searched FTE and saw the following suggestions: master cylinder leak, abs valve problem, air in system, stuck caliper piston etc.

Then I went to the service manual and read the following:

"For example, after braking to a hard stop, the vacuum in a diesel booster may be significantly reduced. If the driver continues to apply the brakes at the stop, the vacuum will start to build again and the pedal will sink as the increasing boost moves the diaphragm forward. This doesn't mean there is a fluid leak or a malfunction in the system. "

Huh? Maybe i don't have a problem after all. What do y'all think?

thanks, dave in Va

94.5 f350 kabinchassy