I completely rebuilt all rear drum brake parts on a 99 Ford Ranger, new springs, shoes, cylinders, and drums. Today I took it for a test run down around town and the highway, and checked them when I got home. One wheel was fine, the other rear drum was smoking hot. Taking it off while hot, about 2/3rd of it was a light purple color, which has persisted after it cooled off. So my question is, what is the chance it would be considered OK to reuse it, or is the heat damage beyond the point of re-use ? So what would a professional auto mechanic advise me to do ? I understand that working in a profesional setting, he might tell me to replace it. But if HE had done this at home on his own car, would he also replace it, or reuse it, assuming the vehicle is a daily driver, not a performance or expensive vehicle ?

Any advice appreciated. A new drum is $45 plus tax, so I'd like to use it again, but not if it has been damaged beyond being salvageable. FWIW, I doubt if I drove it more than 10 miles before I pulled it off while hot.

The drum doesn't sound that bad, but I'm wondering about A, the condition of the shoes, and B, why the brake dragged that hard in the first place.

Have it turned in case of warping. Else, I’d use it on my 96 Ranger.

That said, I’d also keep an eye on it for cracks in the future, and be prepared to replace it next brake job. I don’t think it would catastrophically fail.

Do you know what caused the problem ?
Such as a Self-Adjuster on backwards ?

I THINK I may have adjusted my initial contact amount between the shoe and drum too close. You're supposed to BARELY feel or hear any contact after you adjust your star wheel for the spacing when you place the drum. So, I think I may have adjusted it with too much contact. The other possibility is that I did not check that the cylinder actuators moved freely left/right after inserting the old steel actuators into the new cylinder (you can't buy new actuators). Regarding installing the star wheel backwards or failing to place the longer of the shoes on the back side half of the wheel, I already checked that. I took pictures of the various details and double checked them as I was installing all the new parts. And there is no obstruction of brake fluid in the brake line that I can tell.

Regarding the shoes, I'm going to lightly sand the shoes that glazed over, and replace the drum. No need to put a purple drum back on, as my favorite local parts store exercised the warranty for me even though the part was not defective. I was clear to them that the part was not defective that I burned it myself by some mistake I made, but they did it anyway probably because I give them lots of business on a regular basis, and know them by name etc. I use them because two of the guys in there are motorheads and older racers with varying amounts of pro mechanic experience in their backgrounds.

The only other thing I can think of was a tube video I watched about some piston canal in the master cylinder that can get corroded because the brake pedal never goes to the floor until you bleed the brakes manually. I did that first, but gave up and purchased a pressure bleeder kit that attaches to the master cylinder, no more brake pressing with your significant other cursing you for making them pump a brake pedal.

Anyway I'm going to try again, but this time I'll drive a block and stop to check the drum temps, then four blocks, and so on, before I commit to a highway check. If it's still dragging after that I'll give it to one of two shops use.

I actually rebuilt these brakes about 20 years ago with no problems, apparently my brake repair skills have not improved since then. But I usually do front calipers more often since rear drums (for older cars) don't wear as fast as fronts do.

Come to think of it, I doubt that any modern cars and light trucks are using drum brakes for the primary braking function for the rear wheels. Is this your guys' understanding ?

^^^^^ 18 wheeler big rigs are drum brake.

My buddies who drive 18 wheelers tell me that one of those infrared thermometers on a pistol grip thing does an great job of checking brake chambers and axle temps. General theory is to check every time they stop and if one is hotter than the others it's time to check further.
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This message has been edited. Last edited by: OKCGene,

You should make sure your park brake is releasing properly, assuming the park brake struts are still in place. A park brake not fully releasing due to a rusted cable will cause the same failure to occur again if not corrected. Make sure the shoes stay on the anchor pin when you smack them fore and aft. If the shoes lift off the anchor pin, you have a problem.

Maybe not considered "modern" but my 2001 Ford Taurus has drums in the rear wheels.

PC

Make sure the primary shoe is towards the front. Primary shoe is the shorter one. Also check and make sure wheel cylinder is working properly.

Once you've figured out why you had this problem and corrected it, drive it and see if it feels like it warped from the heat. If not, drive on.

Find and repair the problem, then I'd reuse the brakes and drum.

quote:

old fashioned

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99 Ford

Just reading that made me feel old.

 
Toyota FJ-40 uses 2 wheel cylinders per wheel. 4 different part numbers per axle because on each wheel one has the star wheel at the top and the other on the bottom, and reversed for the other side. Then you have to adjust two star wheels in tandem to get the right contact. Not only that, the star wheels are much different, having tiny slots around the wheel and a tiny hole in the backing plate. Toyota makes a special brake spoon just for these, or you can get by with a screwdriver. Other than all that, the shoes and springs are pretty much like any other drum brake setup. Now that the FJ is gone, the Toyota spoon is used just as a small pry bar.

A few years back, a member made a comment that he never had trouble with drum brakes. That really made - and makes - me laugh.

quote:

Originally posted by wrightd:

Come to think of it, I doubt that any modern cars and light trucks are using drum brakes for the primary braking function for the rear wheels. Is this your guys' understanding ?

2021 - Toyota Tacoma. All Tacoma’s come with rear drum brakes. If you badmouth the rear drums on the Tacomaworld forums, you will quickly learn that the rear drums of a Tacoma are magical brakes that were touched by Jesus.

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If you badmouth the rear drums on the Tacomaworld forums, you will quickly learn that the rear drums of a Tacoma are magical brakes that were touched by Jesus.

If you drive through water deep enough to reach them, drum brakes stop working and stay that way until they dry again. Lightly dragging the brakes while in the water helps a little. However, the Tacoma drums are pretty substantial and don't wear out often. You're more likely to puke a wheel cylinder or axle shaft seal than actually wear the shoes out.

Sometimes in humid climates, drums get a thin layer of rust on the braking surface after sitting a while, which makes the brakes grab and skid until the rust is scrubbed off.

Update. I replaced the drum, sanded the glaze off of the overheated pads, backed off the wheel 100%, and drove it about 50 miles today, about half on the highway. Stopped and checked the temps periodically, no problems. Drum temps were good the whole time.

BUT, I didn't exercise the emergency brake this time. I'm going to inspect the braking cable system, possibly clean and lubricate it, and re-test (close to home). After that I'll be in the clear, because I know the driver uses the emer brake from time to time when parking on inclines etc., and wouldn't want her to discover burning brakes after releasing the emer brake after parking on an incline.

After that, transmission and radiator flushes, and I might expect that truck to go another 50k without issues. That truck is like a go cart, I forgot how fun it was to drive.