Rear drum Extremely hot after driving.
 

ill try to keep this as short as possible. all help is greatly appreciated.

1. i had a problem where when i came to a complete stop my rear brakes would stick. i adjusted the shoes so that they were more snug on the drum. this got rid of the sticking.

to be honest i think i may have had them too snug on the drum. after a while of normal back and forth to work etc, i hit the highway and i could hear the vibration/ dragging from them being too snug. this ruined my driver side rear wheel cylinder (saw the leaking on the back side of my tires) so i changed both cyllinders and bled brakes, also i sprayed the area with brake cleaner. (i didnt have alot of brake fluid left so ill admit, the brake fluid is dirty but the lines were bled properly and the brakes feel great)

since i had the wheel off on each side, i also backed off on the how snug i had the shoes to the drum. at first i was getting smoking from the driver side drum (bout 10 days ago), but now i get this scraping noise when im driving at low speeds, especially when im making a turn. seems like it goes away above 20 mph.

i have new shoes but i didnt put them on yet because its been cold as heck outside. it will be warm this weekend so ill change the shoes then.

do i need to back off even further on how snug the brakes shoes are to the drum?? i drove for about 5- 10 minutes locally today, when i got home i could smell a little smoke from the rear drum so i took some snow off of the ground and placed it on the drum. needless to say it started sizzling like crazy. the drum was about as hot as a frying pan smh


im sure one of you gentlemen is more knowledgeable than me. can you help me thru this problem?? as you can see im not completely clueless so i should be able to work it out with some decent instructions.

i also tried to search the problem on here. i got one thread with one reply but it only discuss front disc brakes.

if there's a link i missed ill gladly read up. id prefer to have this thread replied to tho


i have a 97 4 door 4wd 4.3 front disc/ rear drum blazer

thanks in advance

With the rear drums, you can adjust them in reverse, try that and see if it works.

Put the truck into reverse in a parking lot, hit the gas, get up to about 10mpg, and apply the brakes pretty firmly, almost locking them up (basically slam on the brakes)

If the shoes get brake fluid on them, they're junk, replace them. Little shoe toward the front of the vehicle, big shoe toward the rear of the vehicle. As for adjusting.... During assembly, make sure the adjusters turn freely, clean and lube the threads. When you put the drums on, the shoes should be adjusted so that you can just hear the shoes drag. You should not FEEL a drag when you turn the drums by hand. The self adjusters will do the "fine tune adjustment".

When you apply the brakes going forward, the shoes rotate slightly on the backing plates. Driver side shoes rotate counter clockwise, passenger side clockwise. They remain in that rotated position until you apply the brakes when moving in reverse. Then the shoes rotate the opposite direction. When they rotate in reverse, the self adjuster will tighten the adjustment, if necessary. They only adjust in reverse, and they will not over-adjust. A lot of people think that driving in reverse and hitting the brakes a bunch of times is enough to adjust them. What they don't realize is the shoes rotate on the first application only. One chance to adjust them. The brakes need to be applied while going forward to rotate the shoes for the next attempt at adjustment in reverse. Gotta hit 'em quick & hard, more like a jab and release on the brake pedal, if they lock up, it means you hit 'em hard enough. The farther out of adjustment they are, the more times you need to do it. After a few times, you'll notice the pedal height start to increase. So, forward and apply the brakes normal, come to a complete stop. Reverse, 5-10 mph is plenty fast, jab 'em quick & hard. Repeat as necessary. If you do this once a week, maybe 4 cycles or so, the rear brakes will stay in adjustment, and make the front brakes last longer ;)

Appreciate the responses in here. Its been awhile but this thread has helped alot.
Unfortunately, I haven't gotten to the bottom of this issue yet. Ive gone thru two rear wheel cylinders. Something is cracking them so I think there is damage to the rear axle or something. Ive noticed that there is a noticeable amount of "play"/ movement when putting the drum and wheel back on (driver side). It makes it kind of tricky to put the drum on. There is a ring that keeps coming loose. It sits behind the mount for the drum itself, it looks like it goes to the inner bar of the rear axel. I jam the ring back into place but when I sit the car back down on the ground I hear a bang almost like it popped back out. Last time I took the wheel off the ring had come loose so im assuming it did again.
Another issue which I believe lead to this. When I followed the first replies to this thread, I replaced the rear wheel cylinders and drums on both sides. I noticed that one side had newer springs and the other side had what looked like the original factory springs. I bought a new set of springs and when I had everything apart, I laid each old spring next to the new springs I just bought to make sure I had everything for re assembly. The new spring set didn't have the spring for the adjuster so I had to use the old one. The adjuster arm doesn't seem to fit properly after the first cylinder cracked. I think that in turn damaged the whole attachment to the axel and now i think the whole wheel is unstable.

The problem is the backing plates are worn and or rusted out. As a result, the wheel cylinder will not stay in the correct position. The axles have to be removed to replace the backing plates. Most auto parts stores stock, or can get them. Usually around $20 each.

I think there are some things that might be something to pursue. Parts popping out in the brake assembly sounds like you may have a bad rear wheel bearing. This will let the axle assembly sag down and ride on the top of the shoes, right at the wheel cylinder. That will cook them for sure. It's also possible your rear flex hose is partially collapsed inside. Since there are return springs, it does have a little reverse pressure when you release the pedal.

I called autozone and they told me there is no backing plate available for rear drums

Another reason to avoid that store.


Give this part number to your new favorite auto parts store:
http://www.dormanproducts.com/gsearc...eyword&q=13867
Nevermind what the Dorman website says for model years, the same backing plate is used through 1997 on S/T series vehicles with rear drum brakes.

The image below indicates where the backing plates wear if they are not regularly lubricated. All six surfaces on each backing plate must be flat. If/when they wear, it allows the shoes to move inboard and lose contact with the wheel cylinder pistons. If/when they lose contact, when you apply the brakes, the pistons will fall out and you will lose brake pressure. These plates are designed for use with #514, 9.5" x 2" shoes.

Attachment 31430

**Update with pics**

i couldnt definitively say that the backing plates were whats needed or the only thing thats needed.
so to be sure i took about 7 or 8 pics to have you gentlemen take a look for yourselves.

im pretty sure when you see the damage you'll be able to pin point the problem. the weather is breaking so ill have plenty of time to work on it and post results

ok here is a basic view with the wheel off, as you can see the pads are worn all the way down at the bottom of both sides

http://i3.imageban.ru/out/2014/03/22...efa7be14f3.jpg

here's a quote from one of my previous posts, and the pictures that follow are a visual of what im talking about. (i use a flat head screw driver to hold the ring in place in one of the pics so i could take a good pic)

this is the ring i was talking about

http://i2.imageban.ru/out/2014/03/22...04dae3d850.jpg

http://i3.imageban.ru/out/2014/03/22...23b254892b.jpg

http://i3.imageban.ru/out/2014/03/22...02a6e96a57.jpg

now here is a pic of what i think is major damage to what captain hook called the backing plate. please correct me if im wrong.

http://i2.imageban.ru/out/2014/03/22...28bfe8a645.jpg

this is that same view, only this time i "jammed" the ring back in place. just to add on to your understanding and show where that ring goes since you gentlemen are only seeing pics

http://i3.imageban.ru/out/2014/03/22...e47c80b7a1.jpg

this is the back side of the backing plate. you can see the bleeder and the fluid line. the damage is to the left on the axel

http://i2.imageban.ru/out/2014/03/22...2266f700bc.jpg

and as i said before, what ever is wrong is cracking the rear wheel cylinder everytime i change it. this is a pic of the current one thats cracked (red arrow points to crack)

http://i3.imageban.ru/out/2014/03/22...dd33772f70.jpg


once again, i appreciate any advice or help you guys can give. i just want to make sure i understand whats going on and what and how to fix this before i start taking things apart. i never worked with an axel but imho im pretty good with fixing things and i can get the resources to get the job done. thanks in advance.