how hot do drums get?

[Sovereign]

I recently redid the rear brakes on my 86 C10. New Bosch shoes and had the drums turned. It's the light duty setup so 11" drums with 2" wide shoes. I've put everything back together and adjusted the shoes so they were dragging just a little. I could easily turn the wheels. It's not as free spinning as the fronts but I'm not fighting to make a revolution.

After a short 4 mile drive with minimal braking, my drums were getting up to 100*C while the front rotors would be at 30*C. So I adjust the screws for the shoes in a bit and go for another drive, same issue. This next time, I turn the adjuster all the way in on one side only. Go for a 5 mile drive and that drum is at 60*C while the other side is 150*C. This was expected and what I hoped would happen.The problem is now that the pedal is soft since the one side is adjusted in so far.

What am I dong wrong? Every time, the drag on the drum is what I would consider minimal but they were still getting very hot in a very short time with minimal braking. The front rotors are always significantly cooler after my test drives. I can adjust the one shoe out a small amount or just back up a few times and press the brake to self adjust the pads. I'm afraid I'm just going to be right back to the high temperatures in the drums again. It's been a long time since I have worked with drum brakes, but I don't remember them getting excessively hot. Other than the heat, the brakes felt and worked great. I'm concerned something is not right and will cause serious issue on a longer drive.

I have the shoes with less material facing towards the front of the truck. The brakes I replaced were good. I only did the brake job because I got gear oil on the pads changing the rear gears. The one difference I have noticed between old and new pads is the friction material on the old pads that faced forward didn't extend so far up towards the top and bottom of the shoe. From what I am seeing for shoes online, that seems odd and what I have on now is correct.

Any thoughts?

Thank you

[Dead Parrot]

Quick adjustment trick. Adjust both to be in/soft. Back the truck up several times getting to about 10~15 mph, then sharply stop. The rears should self adjust.

Make sure your e-brake is loose during this, then adjust as needed once the rears finish adjusting.

[cadillac_al]

If they are heating up then they must be too tight. Just a light drag will make them heat up and the heat just makes them tighter.

[truckin 79]

I recently had a an issue when I came to a stop and started again, something felt like it would let go when I accelerated. Well it turns out the shoes would expand but would not contract on rear drivers side. I took drum off and pressed on brake pedal and could see the shoes were hung up. I greased the contact points between shoes and backing plate and that did it. I replaced drums, wheel cylinders and shoes not long ago. I wiped down backing plate but never really cleaned it. In the spring I am going to take everything apart again and clean backing plate and switch to all new brake springs. I am also going to change the rear rubber brake line as well just to make sure everything is new. In the end maybe check and make sure the shoes are contracting and the brake shoe springs are not weak or shoes binding on contact points of backing plate

[1976gmc20]

Axle bearings running hot and you just now discover that after replacing brakes?

[Sovereign]

Originally Posted by 1976gmc20

Axle bearings running hot and you just now discover that after replacing brakes?

Axle bearings are new. I rebuilt the whole rear end when I put the 3.73 gears in. I noticed the drums getting hot from my break in drive with gears. Everything related to the gears, including the axle bearings, is good to go.

Originally Posted by truckin 79

I recently had a an issue when I came to a stop and started again, something felt like it would let go when I accelerated. Well it turns out the shoes would expand but would not contract on rear drivers side. I took drum off and pressed on brake pedal and could see the shoes were hung up. I greased the contact points between shoes and backing plate and that did it. I replaced drums, wheel cylinders and shoes not long ago. I wiped down backing plate but never really cleaned it. In the spring I am going to take everything apart again and clean backing plate and switch to all new brake springs. I am also going to change the rear rubber brake line as well just to make sure everything is new. In the end maybe check and make sure the shoes are contracting and the brake shoe springs are not weak or shoes binding on contact points of backing plate

I did not grease the contact points. I should probably do that. I don't think the shoes are getting hung up though. I can easily slide the drums on an off.

Originally Posted by Dead Parrot

Quick adjustment trick. Adjust both to be in/soft. Back the truck up several times getting to about 10~15 mph, then sharply stop. The rears should self adjust.

Make sure your e-brake is loose during this, then adjust as needed once the rears finish adjusting.

This will be the next thing I do just to see where the system wants to be.

Originally Posted by cadillac_al

If they are heating up then they must be too tight. Just a light drag will make them heat up and the heat just makes them tighter.

Shouldn't there be just a little bit of drag when you adjust the shoes out after installing?

Thank you, all. I appreciate the information.

[1976gmc20]

Shouldn't there be just a little bit of drag when you adjust the shoes out after installing?

Yeah, just barely touching. I used to repair/replace drum brakes all the time when I worked at a service station. I never greased contact points and never to my knowledge did we have them heating up like that.

If the brakes were that hot then you probably couldn't touch the wheel from the outside, which is how I check stuff at rest stops on a long highway drive.

I did have an old pickup that the automatic adjuster on one side would over adjust and eventually lock up that wheel. I finally just took the drum off and flipped it so it was manual adjust only. But you would know because you couldn't get the drum off without manually de-adjusting if that was happening.

I dunno - maybe there's some weird new brake shoes causing this?

Axle bearings are new. I rebuilt the whole rear end when I put the 3.73 gears in. I noticed the drums getting hot from my break in drive with gears. Everything related to the gears, including the axle bearings, is good to go.

Or maybe not?

[Sovereign]

I put my hands all over the rear housing checking for heat related to the gears and bearings. I felt nothing hot. I also hear nothing from the gears or bearings as I drive the truck. My truck is quiet for a C10.

Correct, I can't touch the drums after my short 5 mile drive with minimal braking. The heat is that intense. Meanwhile, touching the rotors is no big deal.

Thank you

[kglowacky]

maybe adjust them all the way in and see if you still get excessive heat . my memory says there is a rubber hose above the pumpkin that could have collapsed causing the brakes on both sides not to release quick enough/