Brakes
Asked by GuruD47HJ Aug 03, 2017 at 09:38 PM about the 1994 Ford F-150 XLT LB
Question type: Maintenance & Repair
I have a 94 f-150 had to replace a rear brake
cylinder. I have bled the brakes 3 times.when i start
the truck the pedal still goes to the floor.i have
tripled checked for leaks and cant find any. Does
the master cylinder need to be bled as well??
2 Answers
If air gets into the master cylinder, then yes. Here is something to consider. Your truck is over 20 years old. The bore in the master cylinder is a lot longer then the normal travel of the piston when the pedal is pushed. As a result, corrosion can build up in the bore, making it rough, at the far end where it is never used. Pushing the pedal to the floor can cause the rubber seals to come into contact with the rough area of the bore damaging the seals. If damaged, brake fluid will leak past the seals back into the bore causing reduced braking levels. If there are no leaks and no air is coming out when all wheels are bleed, it's probably the master cylinder.
Thank you this is what I was wanting to find out. Dad doesn't seem to think it's ty he master cylinder yes it's and old northern truck so rust from the salt up there I've replaced brake lines, back guts of the drums and brakes..