This is getting to be a long story but here goes. I have a 1999 Cherokee that I have owned since it was new. It has almost 180,000 miles on it, and it has been a very good vehicle for the most part. The front discs/pads have been replaced several times with no problems. I don't think the rear brakes were ever worked on until now. A few months ago I decided to replace the rear shoes, since they were probably getting quite thin by now. They were working fine and not making any noise, I just thought it had to be about time. Since I couldn't get those old drums off, I took it to a mechanic. He said yes, the shoes were about gone, so he replaced them as well as the wheel cylinders. A week or so later, they began squeaking, so I took it back. I asked him why he hadn't replaced the drums. He told me the drums looked ok, but he agreed to change them then. It was ok for awhile, but the squeaking returned in about a week. The drums were also getting extremely hot. I took it back again, and this time he replaced the shoes (again). He seemed to be out of ideas, but hopefully this would do it. Well, a week or so later, same thing! Drums, especially the left side, getting very hot, along with the squeak squeak squeak at low speeds. Also there was pulsing in the brakes. I took it to a different mechanic, who put in a new hardware kit. He couldn't find anything wrong, probably because it only squeaked and pulsed when they got good and hot. Well the problem returned AGAIN. I decided to put new drums on myself. It was fine for awhile, but that persistent problem kept coming back. I also loosened the emergency brake cable, it seemed a bit tight. That too seemed to help for a while, but the same squeaking, pulsing and heating came back. I finally broke down and took it to the dealer, where I should have gone in the first place. He told me the brakes had been adjusted way too tight, causing the drums to overheat and warp. Success at last, or so I thought. They turned the drums and adjusted the brakes properly. It was great! Finally fixed I thought. But now a few days later I've noticed that same annoying squeak squeak squeak is returning. It happens after I have driven awhile. No pulsing yet. I do notice the left side drum gets warmer than the right, it was hot once when I got home. Yesterday I deliberately drove several miles at high speed while avoiding any use of the brakes at all. When I came to a stop after that, the drums were cool, so that tells me they're not dragging, at least not right now. I am open to any suggestions anyone might have. Three different mechanics can't seem to figure this out, and it's about driving me nuts! Help!!
I'm glad the dealership mechanic realized that, first thing that would have popped into my mind is the adjustment being too tight and dragging. Not many people work on drum brakes anymore and don't have enough experience on adjustment.
Where the brake shoes touch/ride on the backing plate there needs to be some sort of grease applied. You can use anti-seize or brake pad slider grease, don't go crazy. This should stop the squeaking noise when they are applied.
It is also quite possible that the drums were turned too much and are now too thin and prone to heating up/warping. There will be a thickness spec in the manual.
If you jack up the rear end and spin the tire do you hear this squeak?
Drive it for a while, atleast until the problem side starts to get warm. While its still hot, jack up the rear end and spin the tire by hand and see how much drag you have. If it seems like too much, adjust the brakes then drive it again. If it keeps ocurring, it sounds like you have something that is hanging up, causing the brakes to drag. Could be a faulty wheel cylinder or improperly lubricated parts.
1996 Jeep Cherokee- Project-- Rusty's 8in long arm, SYE kit, Teraflex driveshaft, Cragar soft 8's 15x10 with 33x12.5 Firestone Destination MT's, Eaton Tru Trac in the front
So now I took the Cherokee back to the first mechanic. (This is mechanic visit #7) Told him this whole long story. He determined that the fluid pressure was equal going to both rear brakes. He agreed that the left rear drum was getting extremely hot. This time he replaced the wheel cylinders, and said they weren't heating so much after that. It seemed ok to me for a while, but now the OTHER SIDE is getting hot and the left side is cool. ??? Everybody is stumped, but he did mention the proportioning valve as a possibility. Could that be? I've heard they rarely fail, and can be a pain to replace.
Proportioning valve only controls pressure between the front and back brakes. Sounds like you have an issue side to side on the rear.
It does sound like an adjustment issue however if you are sure that's been corrected, here are 2 more things to consider:
1) grooves in the backing plate behind the shoes. At that mileage on original shoes, the grease between the shoes and the backing plate was long gone a long time ago. The shoes can begin to wear a groove in the plate. Your new shoes, being thicker, are riding further back (toward the axle centerline). They may be trying to drop into the old groove when you try to apply the brakes and then the return spring isn't strong enough to pull them back up and out, hence they drag too much and get hot. Take it all apart and if you see a wear groove, grind it out or replace the backing plate.
2) the brake hose jumping from the axle to the body. At that age and mileage, it may be starting to close up internally which could "hold" back some pressure - maybe more than the brake return springs can overcome, causing the shoes to "hang". I don't know of this ever happening to drum brakes but it did happen on a rear disc on my Taurus.
Ok, problem solved, finally. The left rear wheel cylinder was defective. The first mechanic did NOT replace it like he said. He may have honed it, but it was the old one. It was releasing slow. Anyway I replaced it several weeks ago now, and so far, so good. Drum temps have been fairly consistent between the two sides, so keeping my fingers crossed but it looks good. Thanks to all for the help!