I have a 99 f150 4x4 that has done this twice, once last year and once this year during hot (90+) weather. I'll notice the vehicle seems like it doesn't want to go. Park overnite and it will work ok. Last time it happened the other day I stopped at wally world and both front wheels were real hot and I could smell the brakes. Came out hour later and when I pushed the brake pedal to put it in gear the pedal went to the floor. Pumped up pedal and drove off but truck would barely move, drove 10 mph to a buddy of mines shop and it sat overnite and worked perfect the next day. He inspected everything and seems to think it might be the abs control unit. He noticed a small amount of fluid had come out of the unit and dripped on the ground. I thought I would get on this forum and see if anyone had seen this before? Thanks
Also no abs light or brake light has ever come on

 

Sounds like the pads are sticking to the rotors, and the caliper pistons are either stuck on or clipped on, the pads. Sometimes, a collapsed front flex brake line will collapse internally and block flow, but that would be a little rare on both wheels at the same time.

If there are no "pending codes", and no warning lights ( red for hydraulic pressure problems & yellow for electrical stuff like ABS sensors or ECU), I'd cycle new brake fluid through the system and flush out any possible moisture or air, check fittings for leaks, check the front flex lines.

If you do all that, and can't find anything obviously wrong, check the wear on the pads. If they are more than half gone, I'd switch them for a set of ceramic pads. If they are REALLY worn down, the caliper pistons might be sticking from over-travel, but I doubt this is the problem, but it could be, especially with any moisture in the system. The pistons could be corroded and sticking in the bores. It really sounds like overheated pads sticking to the rotors. Ceramic pads will fix that ( for about $60.00).

Dave

 

I'd wager either worn or dry caliper pins (might try greasing them) or sticking caliper pistons. If the brakes are dragging severely it may overheat the brake fluid causing your loss of braking.

I had a similar problem on a Mustang, but it was only one side and I fixed by buying a rebuilt caliper.

 

If you do choose to go to ceramic pads you will need too change the rotors. if you are changing from semi-metallic to ceramic you will have problems stopping for sure. it sounds like you may have problems in the calipers or lines though.

 

It's happening on both sides, calipers move freely. I would think with sticking pins or collapsing lines it would probably be one side. Pads are about half gone. I thought about old fluid but my mechanic says "not likely it is clean." He's thinking abs controller but that thing is like $1400.00. I appreciate more ideas.

 

I am still having trouble with the brakes on this truck and I was hoping to maybe get some more ideas. I don't drive the truck alot, and the brakes were not dragging all the time but I had them do it recently and the dealer suggested new master cylinder, we replaced it. Then I got the pads changed and the rotors turned and a bad rear ABS sensor replaced. Got truck back and now the brakes are dragging all the time. It is on BOTH sides. I can't believe it! I'm leaning toward the ABS control unit being bad but that thing is EXPENSIVE. Any ideas appreciated

 

Still sounds like sticking caliper pistons. The fluid doesn't have to be very dirty, it just needs enough moisture to corrode the pistons/bores. Pedal pressure will still engage the brakes, but the corrosion prevents the pistons from backing off a few thousandths when you let off the pedal.

Dave

 

Ya know, it was done all backwards.
Why would the rotors and pads be a cause for sticking, as the 'root' cause.
It's the calipers that are putting the presssure on the pads and discs for whatever reason.
Next time get under and open the bleeders to see if the calipers back off.
If yes, it's not the calipers either.
Normally when replacing pads you force the caliper pistons inward to make room for the new pads. This would break a corrosion issue for the most part as well as back push fluid into the master cylinder resevior.
Find out what's causing the pressure lockup to happen.
Good luck.

 

I had one side do the same thing. It got so hot it melted the center cap off of my wheel. I had ceramic pads on it, I tore both sides down because if one did it the other side could go also. All of the pads were cracked down the middle, I replaced both calipers, turned the rotors and AutoZone replaced the pads under warranty. The new pads had saw cuts in them where the old ones were cracked, must have been a heat thing with the ceramics. That was over a year ago and no more problems. Sorry for the long post but I thought I should explain.

 

How would you go about troubleshooting "what is causing the pressure lockup to happen"?
Whatever the cause, it is doing to both sides equally or it would be pulling to one side. Am I thinking right here?