On my F350, 1990 diesel four door pick up, I have the problem of having the rear brakes lock up when I need to use them more that you might in a normal slow roll to a stop light. At first they remain locked only slightly, you can feel them pull the truck to a stop at a very low speed, and then as I drive on, they will often continue to sieze until they will begin to smoke and finally, after stopping, remain locked up completely. The truck will not move under it's own power. After allowing them to cool, they resume normal operation. (well, normal until it happens again) Other clues are these, the "rear anti-lock" warning light comes on when this happens. also, the engine running seems to exacerbate the problem (vacume problem?). I have looked at the auto adjustors and although the shoes are low, there is plenty of distance between the surface of the material and the rivit head. They could be replaced, but this is not the problem. The e-brake works normally and is not sticking, the front brakes seem OK and work well with minimal pedal effort.

Has anybody any experience that will give me a clue as to where to begin. All the shops want to do is to begin replacing everything ... I can do that myself! I'm hoping someone will have already skinned this cat and can start me down the road to recovery. Thanks for reading this far and do help me if you can.

Cheers

 

I'm not sure about this newer stuff, but in an older one I'd suspect the master cylinder not returning all the time.

Dave

 

That points to a bad brake booster.

Also note that there are actually 2 different shoes for drum brakes, the leading shoe should have slightly less material on it compared to the trailing shoe. If these are mixed up the rear brakes are prone to locking... experienced this myself.

 

If the anti-lock light is coming on it is in the anti-lock system probably.

Possibly needs bleeding.

 

As to the master cylinder not fully retracting, would that not affect both front and back? Perhaps not, but if you know for sure, I'd appreciate a comment to that effect,

As to a bad booster, I should have included the fact that releasing the vacuum there does not always have the same effect, it works once in a while which is probably coincidental with the real problem, whatever it may be.

The shoes are mounted correctly and that was a proper item to look for, however before this problem began, they worked flawlessly. If they were recently installed I would be more suspicious of them.

As to the Anit-lock being the problem, I have no clue what that means. Sounds reasonable but where do I look and at what do I look to either asses the situation or to replace the "anti-lock" thingie ... that being a very technical term used in my garage often.

 

These guys are all way off.

I have seen this exact same problem on many Ford trucks. Your ABS valve is clogged up. When you step on the brakes, it engages the rears, but the clogged valve prevent the shoes from retracting. Eventually the springs win and they push enough fluid through the valve that the shoes can retract. The ABS light coming on is a dead giveaway to this problem.

You can either replace the ABS valve, or bypass it with a piece of brakes line. The RABS on these trucks works so poorly it's not worth fixing IMO. If it were my truck, I'd bypass the line, bleed the whole system out really good, pull the fuse and the light bulb for the ABS and forget about it.

 

That is way true. I just yank the fuse on the RABS as one of the first upgrades I make to these trucks. That won't help this guy, tho, since his ABS valve is gummed up or could it be the rubber brake hose collapsing internally?

Either way, the RABS on these trucks is useless, and the RABS my 2000 Super Duty was no better. In fact I would call it dangerous.

 

The rubber hose isn't strong enough to prevent fluid from being pushed back because the springs, especially on a HD truck, are more than strong enough.

 

Perfect, that is the only thing that takes into consideration all of my symptoms. Thanks tons and you know that will be my target ASAP. Ps. I am intrigued by your signature line re: evolution ... we are opposites on that item, but then your comment about not needing to study a subject would permit me to disagree while respecting your opinion ... at least we agree on our Fords ... thanks again!

 

Well, there's a story about that line. I certainly never said that. Someone sent me a link to a website of the 100 greatest quotes from christian fundamentalist chatrooms, and that was one of them.

If you're a a sponsor, you can see the thread in the clubfte forum. It sparked a really good discussion, as there are quite a few members here on FTE who won't acknowledge evolution. I'm not one of them.

 

Even more interesting to know the history of that line. I may have suspected that it came from a fundamentalist group and being an ex-member of said group I have a nose for that type of toss away line. Not to belabor the point, but it is curious that the more one becomes educated (not schooled) the more one might take exception to the "God said it, I believe it and that settles it" type of reasoning. A recent read of mine was about the history of the copying of the text of the Bible. The hands that it passed through while the only means of reproduction was one letter at a time by a person who could copy letters and not read, may have added some level of misquotation to the book. I see we are nearly neighbors, Rough and Ready here, so we may cross paths one day. Keep truckin' and helping others ... it's a gift and a talent that few enjoy, Thanks again!

 

Regarding the brake problem ... I bypassed the ABS thingie and it woiks poifectly! Thanks Andy!

 

Where did you get the stuff to make this bypass work? I have looked everywhere for some 3/16" line that has the larger fittings on it like ford uses and a union that has the larger fittings but the 3/16" hole in it. No luck at Napa, Autozone, and a local brake/clutch place either.

Thanks

 

Made it my self by cutting the stupid and frozen bypass valve in half, brazing the ends together so that the hose fittings would not know the difference and put it back under the truck. No valve and no problems! I hope you can do the same.
dbcopper

 

I'm having the same problem. Is the proportioning valve part of the ABS valve? That's the only thing I see, I think, on the inside of the drivers side frame rail.