I recently just bought a 2002 F150 Supercrew FX4. I love it. But just last week I am having a problem with my brakes. When I start driving the pedal feels softer then normal. I know I need to flush the fluid, it looks dirty and there can be some air in the lines. The rear pads and rotors are new, the front pads are new, the rotors where turned. All this was just done piror to me purchasing it. So after driving for a bit the brake pedal suddenly will be stiff and the brakes feel better. Then after I take my foot off the pedal, the brakes are still grabbing the rotors, which is slowing the vehicle down. When I get home the rims and rotors are very hot and stink. Dont know if the mc is faulty, or the proportioning vavle is defective(if there is one).

Help

 

sound like bad master cylinder from the pedal symptoms u are describing.

 

I have a 97 ford F150 Lariat with the same issue. Brakes grabbing and still holding after releasing the pedal. I actually put my foot under the pedal to help it back up. You can feel the pedal travel. Happens after driving a while so if there is air in the lines I suspect the pockets would heat up expanding in the lines. Thought they were well bled but will have to check that again. Any test you can run on the MC to verify it's faulty? Any help would be appreciated. As always...great site!

 

I own a 99 F150 SC 2WD 4wdisc 4wABS and I too am confounded by this front disc issue. It started with the front passenger side caliper problem at arround 110K. I wasn't really that concerned with investigating the root cause. I just felt it was time for servicing. New rotors (drilled and slotted), bearings, seals, and pads. Three weeks later, the driver side caliper started to fail. Again since they weren't changed out, I didn't investigate. I changed the calipers out along with the lower ball joints at the dealer's reccommendation (the ball joints changeout were found to be unnessessary). I'm now spun off into a level of pissed I've not seen in a long time. Dealer provided calipers (rebuilt only not OEM), replacement ball joints (without any means of relubricating).and three weeks later the driver side caliper locks up and destroys the rotor. Again new rotors, rebuilt calipers, pads, bearings, seals. This time during the bleeding process, the passenger side vents like a race horse, the driver side seems to have a prostate problem. When all parts are new and flow appears impaired, root cause analysis is a must(should have done it first)! Bleed all lines starting with the furthest first taking note of velocity and volume. If all bleed the same with good flow look at component level failures. If all are of poor flow look at the master cylinder or the ABS(good luck trying to find the lines for the MC to the ABS). Line condition (rusted) may force a complete line set change even if they are not the source of a restriction(turn one line nut and roll the tube). If only one caliper seems to be affected, the master cylinder is OK but the ABS or the associated line is suspect, as could be the caliper. Please note that if this is a intermittent problem it is not a line restriction or MC failure but a component problem(caliper or ABS). Good luck troubleshooting. Have lots of DOT4. Try speed bleeders. Invest in stainless steel lines. Look for the best, not the most expensive. The F150 rates the best.

 

Glad I wasn't next to you while you were venting. Lol. Anyways we haven't resolved our problem but your right in the investigation part. I read here that the rubber brake hoses are kinda touchy and may be failing from the inside (disintegration). I was cheap (when I did a brake job) and didn't change the rubber lines cause they looked good on the outside. That may be a place to re-start my investigation. As for bleeding, it would depend on how quick you opened the bleeder screw...be consistent and watch the final flow to be steady, air bubble free. That said, it also may be the proportioning valve. To make you feel better, the ball joints would have failed soon enough. Very poor design for not allowing grease nipples. You let it go long enough and it causes more problems. This a known problem with our trucks, especially the tie rods. Had to get mine towed out of the driveway to fix it. Their are law suits on-going about this issue. Anyways, you are right about root causes, keep investigating, reading and troubleshooting, that's why this site is so great, eventually you will find the answer. 4 million heads are better than one.

 

Well finially had time to look at my master cylinder. I check everything else first, and came to the conclusion that the master was it. It sure was. I unbolted it and had to pry it off. It was leaking so it rusted, which caused the cylinder inside to stick making my brakes staying engaged. 100 buckslater well worth it.

thanks