Odd intermittent brake problem - SOLVED!

[Fix4Dirt]

There is, but LS is not a priority. I don't offroad, so with 4WD and my driving ability this truck will go anywhere I want it to. Growing up on a farm 12 miles from town without 4WD or limited slip (or ABS), I learned how to drive on slick and muddy surfaces. I try to use 4WD as little as possible in the winter just for the challenge - as long as there's no other traffic around.

then in that case any low mile 3.73 should do! iirc at the JY around me if i egt one w brakes its 250 iirc...

 

[429CJ-3X2]

This should be my last update on this issue.
The grinding noise was due to the upper front corner of the rear shoe making contact with the backing plate (should be a tiny gap), which pushed the shoe outward so the outside upper few inches of the shoe was grinding against the drum. Seems to be a problem with the backing plate as the old shoe shows signs of rubbing too, but not nearly as bad as the new one. I could have taken it all apart and ground the corner of the shoe off, but that's not happening (see above). Instead I hit the backing plate with a punch and big hammer and gained a little clearance, then took my grinder to the outer steel edge of the shoe. No more noise!

I then adjusted the rear brakes and went for a test drive. Brakes feel and work as they should!

I replaced parts I didn't need to, and spent considerable $$$ I didn't need to - particularly on the booster, but I don't really mind all that. My brake fluid is now clean. I have a new master cylinder - plus the old one for a spare - and new rear brakes. The ABS now seems to work. And I learned a bunch. What I do regret is taking 6-7 weeks to work through all this when I probably could have solved it in a day or two if I had checked the rear brakes at the beginning. On the other hand, the progression I worked through seemed reasonable. In the end, I have my truck - my main vehicle - back on the road, and that's what really counts.

 

[CDW6212R]

Well done for keeping at it until you found the problem. That's what counts, and brakes are something you can't give too much attention to.

 

[oklagp1200r]

This should be my last update on this issue.
The grinding noise was due to the upper front corner of the rear shoe making contact with the backing plate (should be a tiny gap), which pushed the shoe outward so the outside upper few inches of the shoe was grinding against the drum. Seems to be a problem with the backing plate as the old shoe shows signs of rubbing too, but not nearly as bad as the new one. I could have taken it all apart and ground the corner of the shoe off, but that's not happening (see above). Instead I hit the backing plate with a punch and big hammer and gained a little clearance, then took my grinder to the outer steel edge of the shoe. No more noise!

I then adjusted the rear brakes and went for a test drive. Brakes feel and work as they should!

I replaced parts I didn't need to, and spent considerable $$$ I didn't need to - particularly on the booster, but I don't really mind all that. My brake fluid is now clean. I have a new master cylinder - plus the old one for a spare - and new rear brakes. The ABS now seems to work. And I learned a bunch. What I do regret is taking 6-7 weeks to work through all this when I probably could have solved it in a day or two if I had checked the rear brakes at the beginning. On the other hand, the progression I worked through seemed reasonable. In the end, I have my truck - my main vehicle - back on the road, and that's what really counts.

What did you do with your old abs pump and module?
Did you have a abs light on at the beginning of your problem?

 

[429CJ-3X2]

I kept them. The ABS hadn't worked right for some time, and I had pulled the fuse about 3 years ago.

 

[oklagp1200r]

I kept them. The ABS hadn't worked right for some time, and I had pulled the fuse about 3 years ago.

But did you have a abs light prior to pulling the fuse?
Reason I'm asking is because I need a working module.

 

[429CJ-3X2]

Since a dirty or bad sensor or bad hub can cause the light to come on, whether the light was on before I pulled the fuse is somewhat irrelevant. You don't want this module, nor would I pass it on to anyone as a properly working unit.
The truck had a severe vibration when braking from highway speeds for several years. Didn't always do it, but usually, and sometimes was worse than others. I didn't know for certain this was caused by the ABS until I removed the fuse. What prompted me to pull the fuse was when the ABS started randomly engaging just as I came to a normal stop on dry surfaces, allowing the truck to creep forward when it should have been stopped. Both conditions ended immediately once I pulled the fuse. Whether these were caused by the hydraulic or electrical side of the unit (they come apart), I don't know, but as a complete unit, it doesn't work properly.

The '01-02 2 door Sports and the '01-02 Sport Tracs use the same module, and that module is exclusive to the Sports and Sport Tracs. That's what the parts exchange manual at the salvage yard shows. '03 and up have rear discs, so a different module would be used. 2WD uses a different module than 4WD.