I've had a very perplexing problem with my '99 F-150 4X4, and I'm almost to the point of putting a car cover over it in the garage and never driving it again.

Here's the background info on it:

I bought it back in January with 89,000 miles on it. I only drive it on weekends, and it just finally turned over 90,000 -- 1,000 miles in 3 months. I've been doing all the routine maintenance -- complete drain and refill of transmission and torque convertor, coolant flush, spark plugs and coils, drain and refill of transfer case, engine oil and filter, lower ball joints, etc.

Anyway, it was running fine until I did the transmission a few weekends ago. On the test drive, I got this strange clanging noise under the truck and pulled over to investigate. I found nothing wrong, and it drove home just fine. Over the last couple of weekends, a few times when I've tried to take off from a dead stop, it has sat there without moving when I press the accelerator. At first I thought it was the transmission going into neutral, but the engine is not revving up while its "stuck" in a stopped position like it would if in neutral. It's like you are pressing the gas and brake at the same time.

When I accelerate enough, there's a loud clunk and the truck finally lurches forward pretty hard. It's like WHAM!!! It only does it if I've been sitting still for a while -- stoplights or drive-up windows. It doesn't do it at stop signs, since I'm not sitting still very long. It doesn't happen all the time, just once in a while. When it does this, after it does start rolling, there's a rubbing/grinding sound coming from under the rear of the truck for a block or so. The sound seems to correspond with the rotation of the wheels or driveshaft -- noise....pause...noise...pause...noise...

I've thought of all kinds of explanations: transmission, slip yoke, universal joints, rear differential, rear disc brake calipers. I haven't considered the emergency brake, as I have never used it since I've had it (and the pedal is up.)

Does anyone have any suggestions before I just trash the danged thing?

 

interesting... I'm guessing you have drum brakes in the rear, right? If so, your parking/emergency brake uses the same pads as the service brakes, just a different lever to apply them.

So before I scrapped it, I would pull apart the rear brakes and check them out... perhaps something came loose in one of the drums and is hanging up. Not sure why this would be dependent on how long you were sitting still, but perhaps it takes a little while for whatever is loose to settle???

It sounds like you're pretty handy, so I'd definitely give it a try if I were you. Do a search on here and you can find a schematic for rear drum brakes - one of the guys has posted it several times... I think he has a link to a ford bronco forum or something, but they are the same.

good luck!

 

It has rear discs.

 

My 2000F150 made a noise similar to the one described. It never "locked up" the wheels, but turned out to be the emergency brake shoes. They had rusted so bad and broke free of rotors and fasteners. May be worth a look see......

 

I'd check the brakes, especially the e-brake. They are nutorious for seizing but are cheap to fix and easy to disassemble. The part that spreads the shoes seizes, needs to be separated and de-rusted, then anti-siezed together again. See if the outer hook is aimed toward the back or is it pulled towards the front and the spring compressed? If the pedal is normal and it's applied, drive the hook back, hammer and a large flat blade screwdriver work nice. Check the calipers too.

 

Well, I finally got around to disassembling the rear brakes tonight. The driver's side disc/drum slipped right off. Both shoes were demolished, with the metal and brake meterial being separated on both. They were the original shoes. Obviously, this was the side that would grab sometimes when I was stopped and trying to take off.

The passenger's side disc/drum would not come off at first. After prying gently, I looked behind the backing plate and saw that the spring was partially compressed. I used BLUE20004X4's recommended method of driving the hook rearward with a hammer and screwdriver. Even then, it was still a little difficult to remove the disc/drum. The brakes and hardware on this side were completely new. Obviously a previous owner had the same problems with this side as I did with the other. Why they only replaced one side, I'll never know. Either this side was sticking, or they had it adjusted too tight.

I made the decision to just gut both emergency brakes. I removed every single piece of hardware, and placed it all in bags. I've had a driver's license for 24 years now, and don't recall ever using a parking brake. I figure if I want to put new ones in someday, it'll be no big deal.

I then put it all back together and went for a test drive. The truck seemed to have more pep, and actually seemed to accelerate easier. I'd say that those brakes dragging had slowed it down. The grinding noise that I'd been hearing was eliminated. I'll know in a few days if the "locking up" at the occasional standstill has been corrected. I'm confident that it has.

 

Glad to hear you got it!

if you ever get bored someday, you might want to take some time to rebuild the e-brake. Chances are very slim that you would ever loose both circuits of your service brakes, but... ... better safe than sorry some day...

 

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Good job OP, but you really should put the guts back in. It is not much to refirbish the old stuff, wire wheel most stuff especially the hook that spreads the shoes, it separates in 2 pieces with a vice and rubber mallot. Then wire wheel the whole thing and anti-seize the pieces where they meet and pivot on. Once you have that and all the rest of the hardware is good, reassemble and slacken off your adjuster too. Mine's due for a re-do, but has lasted 2 or 3 years without a problem, it takes an hour to do so I don't care.

 

What I don't understand is that the side with the new hardware and shoes was the one that was tightly pressing outward against the drum. Even after releasing all pressure on the cable, it was still too tight to easily remove the drum. I had to pry it off.

The side that was locking up my back wheel on take-off was the one that had the broken shoe material floating around. With the history of the emergency brake shoes on F-150's and Explorers disintegrating, I'll probably pass on rebuilding the set-up. The ones that were broken in mine were paper thin. That means that they had to have been constantly rubbing at some time in the past while they were still intact.

I feel that there shouldn't be any wear on them, as the only time they should be in contact with the drum is when the vehicle is completely stopped and the parking brake is engaged. How the heck did they get worn down to nothing? Even the metal part of the shoe was scraped up where it had contacted the drum.