Drum is stuck

[dmjlambert]

Hi,

If you folks have any clues to give I would appreciate it. I have a 1969 C-10 long bed pickup with rear drum brakes. It is my daily driver. Last night I was pulling into the driveway and had to give it more gas than I thought was normally necessary to get up the incline of the short driveway. As soon as I pulled to a stop I smelled something burning. I got out of the truck and the driver side rear wheel was smoking. I looked back in the truck to make sure I had not been driving with the parking brake on, and I was not. Whew. But it was just the driver side acting up. What I think may have happened is a brake shoe fell apart and wedged itself in there crooked or doubled up or something like that. I would like to know.

I chocked the front wheel and jacked up the wheel and took the rear wheel off, put the transmission in neutral. I'm trying to turn the hub and drum to line up with the adjusting hole so I can back off the adjustment, but I can't turn the drum. Any hints or tips? I have posted here a video to show that the brake is not impossibly tight, I can wiggle the drum just fine.

I tried putting my hubcap tool behind the drum and use a mallet to hammer the drum off, but it won't come off that way. I'm going to go back out there and puzzle over it a while longer while you folks may have time to soak this in and perhaps give me some homework. I appreciate it.

Drum stuck - YouTube

[truckster]

The only thing I can think of is pry bars from the back.

[dagnabbitt]

If it is like what happened to me you wont hammer it off. You need a light and some bendy tools and to go at it from the back. Get in there and wiggle away, save your strength.

[Steeveedee]

Get both rear tires off the ground (you're half way there) after putting the right rear wheel back on. Mark where the adjuster hole is in the drum out on the tire/wheel and use your engine to turn the drum. It has a bit more torque ability that you do!

[dmjlambert]

OK thanks. I put the nuts on to protect the threads and used leverage to move it. Better.

[dmjlambert]

Yes, that is interesting. I thought about leaving the right wheel on the ground to keep it stationary, and use the engine to turn just the left drum while it is in the air, but I did not have enough beer to support my decision making toward that method. The right wheel is turning freely, so I'm sure the engine power would just turn that right wheel if both were off the ground.

Something I did consider is mark the position on the tire, and put the tire on and drive it forward a few inches, then jack it up and take the wheel off. Anyway I did get the drum turned by using leverage, and loosened the star wheel and took the drum off. Here is where we are.

[dmjlambert]

So far I have not found a reason for the smoking. It looks fine to me, other than I have the long shoe in front. So I'm puzzled.

Something I omitted from the story is last week I adjusted my brakes because my automatic adjusters are not keeping them adjusted as they wear. I adjusted them so they were tight and then backed off the adjusters until the drum moved freely. I did that on all 4 wheels. I was needing to get that done because the brake pedal was sinking too low. Every couple of years I need to do that.

I don't have anything funky going on like wrong adjuster for the side of the vehicle or anything like that. The adjuster wheel is just worn too much. I know the parts are right because when I reach in the drum window I am pushing down on the star with a screwdriver to tighten, and pushing up to loosen. I have since the adjustment driven several hundred miles and have not had this problem of the smoking and stuck brake come up. I would think if there was any drag from that adjustment it would have worn off the brake shoes just a little and there could have been smoking slightly on my first test drive after the adjustment, but the truck has been working fine and no problems. Now a week later pulling into the driveway I suddenly have a problem with just the left rear.

In the next couple weeks I'm going to completely replace my brakes with a 5 lug system from a 1971 truck. So at that time I'm going to make sure the auto adjusters are working fine.

I'm thinking of putting the drum back on and adjust it and take it for a test drive.

[geezer#99]

Your shoes are on wrong.
Short pad goes to the front.
That might cause the problem you have.

Memory is fuzzy but I think the brakes are self energizing. That’s the reason the short shoe is in the front.

[dmjlambert]

I had my daughter sit in the driver's seat and depress and release the parking brake. I saw movement in both directions of the lever it moves in the drum brakes. I had her press the brake pedal and saw no movement from the cylinder. I am embarrassed to say here, but I'm just going to say it and you all can scold me, there is no brake fluid in the rear reservoir of the master cylinder. Man oh man. So time to fill it up and then see what I got going on after that.

[dmjlambert]

And of course I'll need to bleed them. I think I'll flush front and back reservoirs and bleed them until all the old fluid is out of the lines. I don't have all my tools handy because I'm down the road apiece (Texas version of down the road apiece, several hundred miles) from my house. So my nephew is coming over tomorrow to help me out.

[cwcarpenter98]

Before you add the fluid, make sure you get your shoes swapped to the correct orientation mentioned by geezer#99 above

[dmjlambert]

Yes and thanks. I’ll get it all straight and working I hope. I may post here again if I run into something more that puzzles me. For now I just have my embarrassing improper maintenance to deal with.

[Warrens69GMC]

Your strut bar has fallen down, resulting in the shoes being pushed farther out.

Or so it looks.

[LNP]

Maybe the wheel cylinder sticks. Could be the parking brake cable doesnt return 100% too.

[Steeveedee]

If the adjustment is too tight, the drum will expand with the heat. Then, when backing up, the adjuster will take up some slack. This can be a vicious cycle. I've had to back the brakes off on people's vehicles at the side of the road in the past.

[don t. - 72gmc]

I would check your brake lines, wheel cylinders and such, before adding brake fluid. If no one has replaced the lines, brake parts, rust/wear-n-tear, you could have a leak. Reason-1 why Im doing a total brake system re-do.

Good luck...Don.

[dmjlambert]

I wish to thank you guys for replying here and giving me all this great info. I'm checking out all the things you are pointing out. This forum is the best there is for social networking on the web, plain old good advice, and friendliness, and I appreciate you folks.

[mrein3]

Originally Posted by dmjlambert

Hi,

If you folks have any clues to give I would appreciate it. I have a 1969 C-10 long bed pickup with rear drum brakes. It is my daily driver. Last night I was pulling into the driveway and had to give it more gas than I thought was normally necessary to get up the incline of the short driveway. As soon as I pulled to a stop I smelled something burning. I got out of the truck and the driver side rear wheel was smoking. I looked back in the truck to make sure I had not been driving with the parking brake on, and I was not. Whew. But it was just the driver side acting up. What I think may have happened is a brake shoe fell apart and wedged itself in there crooked or doubled up or something like that. I would like to know.

I chocked the front wheel and jacked up the wheel and took the rear wheel off, put the transmission in neutral. I'm trying to turn the hub and drum to line up with the adjusting hole so I can back off the adjustment, but I can't turn the drum. Any hints or tips? I have posted here a video to show that the brake is not impossibly tight, I can wiggle the drum just fine.

I tried putting my hubcap tool behind the drum and use a mallet to hammer the drum off, but it won't come off that way. I'm going to go back out there and puzzle over it a while longer while you folks may have time to soak this in and perhaps give me some homework. I appreciate it.

Drum stuck - YouTube

I'm going all the way back to your original post on this thread. You mentioned you checked to make sure your parking brake wasn't engaged. That implies it still works. Up here in the rust belt the parking brake cables rust up. Then when you use the brake, you got leverage with the pedal but when you release it, one or more of the cables is frozen which would cause one or both sides to hang up.

Have your daughter work the parking brake while you observe. A temporary fix to a stuck parking brake cable is to remove the bar that goes horizontal across the top of the axel between the two shoes. You can leave that out and never have a parking brake or leave it out while you hunt down brake cable parts.

A solo way to see if a cable is stuck, and is something I always do after doing a drum brake job - this is hard to describe - with everything assembled and the drum still off, whack the bottom of the shoes with the lower part of each hand, back and forth. The shoes should pivot back and forth and remain in a circle. If the top of each shoe pops out when you hit the bottom, you got a stuck parking brake cable and removing that bar will fix the problem.

[dmjlambert]

I believe my brake lines were restrictive, perhaps collapsed inside the brake hose between frame and differential, and causing the brake to be partially engaged and not fully releasing, which lead to heat build up and cylinder failure. The cylinder was leaking. After replacing the cylinder and brake shoes last weekend I got back home. On the way home I stopped often. One time I stopped in the middle of the trip the wheel was normal outside temperature. The other times I stopped I thought the wheel was excessive in temperature, as in uncomfortable to hold the hub cap for more than 5 seconds. So the problem was intermittent.

This weekend I replaced the brake lines from the front to the back including hose, tee, and lines going to the cylinders. Bleeding was a whole new story compared to last weekend, about 10 pumps of the brake filled the little bottle on the one-man bleeder tool. Much more volume and free flowing this time. Preliminary test drives do not heat it up. I’m going to monitor it for the next 20 or 30 trips and see how it goes.

If this fix sticks it is the same thing as posted by Knanthrup in this old thread
http://67-72chevytrucks.com/vboard/s...d.php?t=609667

[LNP]

Glad to hear you got it fixed. Its not uncommon for brake hoses to fail as they age or something causes damage to it and then restrict the return flow of brake fluid.

[dmjlambert]

Here is an update. As it turns out the problem was not resolved. The driver side rear drum brake overheats intermittently. When I drive around town, when I get to where I'm going I reach down and feel the hubcap. It is same temperature as outside, or it might feel hot to the touch. It has not heated to the point of smoking or that I can feel the drag of the brake engaged, but it is possible I have not encountered that severity of problem yet, and perhaps it's coming.

I don't often set the parking brake, and I don't think it is likely a problem with the parking brake. About 5 years ago I replaced the parking brake cable that goes to this driver side rear brake, because the cable was rusted and binding. The new cable appears to move freely.

To summarize the above posts, I replaced the shoes and cylinder and cleaned up and inspected the brake. I replaced the hard lines from the front to rear, the rubber line, and the hard lines on the differential.

Is it possible my master cylinder is bad, and could that cause just the driver side rear brake to drag and overheat intermittently? I have read they have a 10 lb residual valve in them for each of the brake circuits (front and rear) and I was thinking perhaps that is what is malfunctioning. The residual valve overcomes the spring in the drum brakes to keep the brake shoes nearly engaged, according to what I've read. I suppose there could be a difference in springiness from right to left brakes, but don't know.

I removed the master cylinder and took it up to O'Reilly Auto Parts because it has a lifetime warranty and I thought I would ask them to swap it, but when they tried to do that for me they found the part is no longer available. It was a rebuilt master cylinder and it is 7 years old.

They have offered to refund and then sell me a new master cylinder and I would pay the $50 difference between rebuilt and new. If I do that, the new master cylinder will probably get a couple of months of use before I remove it for a front disc brake swap.

I have a new master cylinder for disc/drum setup, but my favorite mechanic to help me with that whole brake swap is having a personal issue to deal with so we can't start right now. I was contemplating putting the new disc/drum master cylinder on and check it out running it on my 4 drum brake truck. The short brake line that goes from the front reservoir to the distribution block would need to be re-bent to move it out by 3/4 inch if I did that. I suppose I will not have the correct residual valve for the front drum brakes so it may affect the feel of the brakes.

I would be interested to know what you folks think.

[Richard2112]

I don't know if this helps at all but the parts are distinct and this is how my rear brakes are set up on my one ton. Looks similar to your setup, (I think) mine is just bigger. I have never had a problem with the drum brakes and other than what you see, I replaced the return spring on the e-brake cable and soaked my cables in motor oil overnight before installing. They've worked without problems for years.

[Steeveedee]

If the hydraulic lines that feed each side are all new, they can be eliminated as a source of the problem, as can the master cylinder, because the pressure would be the same on both rear wheel cylinders. It's possible that the adjuster is setting the shoes on the LR tighter. Do you check both rear hubcaps for heat?

[dmjlambert]

I adjusted both sides the same amount, and I have checked both sides for heat after a drive. I adjusted them by tightening them with the drum on, through the hole in the drum, pressing the brake, and seeing if they will tighten more, and then I back them off until the drum turns freely. I don't have a lot of faith in the auto adjusters, I don't think they successfully turn the adjuster wheel by the teeth. I probably could just put the master cylinder back on, and loosen the adjuster wheel on the left side by a couple of turns and see what I get. Perhaps the problem is simple, I sure would like to find out that is the case. I read your post about potential for vicious cycle above. I am not understanding the intermittent nature of the problem.

[Ironangel]

Are your existing front drum brake lines 1/4" like the rear? That will require using a 3/16" to 1/4" adaptor if you go ahead and use the disc-drum MC. I'm thinking rust, dirt and debris is in the piston bore of your drum-drum MC intermittently blocking the return port. The disc-drum MC you have shown will work for front drums but the front port is for 3/16" flare fittings, that's where you'll need the adaptor. The reason a drum-drum MC will not work for a front disc is the reservoir size, disc brake calipers use twice the volume of fluid than the wheel cylinders in drum brake applications. If it were me I'd spring for the correct drum-drum MC and be done with it. Take on the front disc swap when it happens. Trade the new disc-drum MC for the drum-drum MC and trade it back when you make the swap...Eliminate the variables.