1995 Ford F150 6 cyl Two Wheel Drive Manual 150287 miles
Customer brought me this truck with a broken left front brake hose and the master cylinder empty. Pulled the front wheels to replace both brake hoses & found the brake pads very thin. Replaced both front hoses, front pads & front calipers. Bled air from front brakes and got decent pedal height; started truck and brake pedal went to the floor every time I pumped it, would not give a good pedal when I had the engine running, only with the engine shut off. I pulled the rear wheels & checked the brake shoes and adjustment, OK; I bled the rear wheel cylinders then the front calipers and still had no pedal height even though the rear brakes were adjusted correctly and I had a good strong emergency brake. I then bled the entire system, including the ABS bleeder valve screw, twice more with the same results (no engine/pedal - engine/no pedal). I vacuum bled the entire system then gravity bled (opened all bleeders) and no change, no pedal when running. I loosened the master cylinder lines & bled it, no air, OK then bled the rest of the system, no pedal when running. I removed the master cylinder nuts & pulled the cylinder away from the vacuum booster; I turned the adjusted on the booster rod out two full turns & installed the master cylinder, no pedal when running. I removed the cylinder and turned out the rod three more turns (total of five turns) and installed the cylinder, no pedal when running. I drove the truck down the road and applied the brake 3 or 4 times; the pedal went to the floor each time but the rear wheels locked up showing that the rear brakes were working normally. I shut the truck off and went to talk with the owner; I asked him if he or his employees had been experiencing any problems before the hose blew and he said they hadn’t, that no one had complained. I returned and started the truck to move to another location and had good pedal! I test drove the truck for about ten minutes; good pedal all the time but I started smelling the brakes like they were getting hot. I brought the truck back and had to leave it to finish tomorrow. I need an opinion on my work and diagnosis of the problem and also any suggestions you might have. I don’t like adjusting the brake pedal height at the booster rod because I believe that is treating the symptom rather than the problem. I plan on turning the rod adjustment back in a couple turns tomorrow and road testing again to see how it performs but haven’t yet understood why I couldn’t get a normal pedal after replacing the hoses, pads and calipers.
Thursday, March 19th, 2009 AT 8:25 PM