The Stovebolt Site Forums The Parking Lot Tons 'o Fun rear brake problems

1953 3800.
I seem to have a problem with my rear brakes. For some reason they are locking up after a short drive. It's almost like the parking brake is on. Has anyone else had this problem? All new shoes and hardware. Now that the weather is better I'm planing on getting out and pulling the drums to see if anything looks off. My roads are VERY rough, and I'm worried that all the bouncing around is messing things up.

Any advice or suggestions welcome.

Tim

May just be adjusted to far out and rubbing and getting hot which make them tighter and lock up. Take a whole bunch out of adjustment like leave a gap. Then drive. Most of the braking is up front anyway. The. Test drive. With some braking. If you lock up. Then it has to be something not retracting right. But since you said all new hardware it should be fine. Then you can start back adjusting shoes closer to the proper setting. And test driving as you go. You can always unhook parking brake to validate it has no cause. Then add it back later.

bluesman Try getting in your truck cold drive somewhere without using your brakes,carefully roll up to a curb or something to stop you get out and see if your drums are warm/hot. If they are warm/hot back-off adjustment. As was said be sure park brake isn't the culprit. when you get on a slight slope and let the pedal off will it roll back ?? It should--if not brakes probably too tight !! Also if you smell them as in hot need loosened-up ! Dought if it's rough roads where I grew up the wash boards were terrible the trucks got thru that.

I had a similar situation . Mine was due to an old brake hose from frame to rear end . It would allow brake fluid to go to wheel cylinders but would not allow fluid to return back . This is quite common . I was able to verify this . When the brakes were not released I cracked a bleeder and could here the shoes retract. New hose , no problem. Note : Do this test in a safe location and the vehicle is secure and will not roll as you release the brakes .

Another way to test this is to drive without using your brakes . I know this can be difficult and may not be possible . Check to see if any drive . If not possible put the truck on safe jackstands . Rotate the wheels and check for drag. If no drag vigorously apply brakes . Now go back and check to see if your brakes are releasing . Try to rotate the wheels. If wheels are dragging crack a bleeder . See if this improves the situation.

It could be something different but if you have new wheels cylinders I doubt whether it is them.

Do you have a service manual? They are pretty handy.

My pal had this same issue and I have given this same answer to others and it helped them. He chased it and chased it trying to find the issue with the brakes, shoes, cylinders, springs, etc. It wasn’t the brakes at the drums at all. It was the adjustment on the push rod of the master cylinder. He got it adjusted properly by an old boy shop and the issues disappeared. Check this. It likely is contributing to your issue, or might be the real problem.

Thanks for all the replies.
when I rebuilt the brakes I installed a new dual master cylinder, I assumed it was designed for my set up. I haven't gotten back out to pull the drums, but I'm wondering if I somehow got the shoes reversed. As I understand it one of the shoes goes towards the front of the truck and one goes towards the back and one of them is self actuating. The thing is, I don't have many miles on the truck since the restoration (like 100 or so) and the brakes worked well until I had to climb the (very) rough steep hill leading to my house. Then they locked up.

One other thing, when I did the brakes orgininaly I noticed that there was a grove worn in the backing plate where there is a flat spot. I think this is where the shoes ride as they move to engage/disengage. Maybe they are hanging up. I don't know if there are replacement backing plates available.

Hopefully I'll be able to get out and dive into things next week

Tim

While rebuilding the brakes on my one ton, I welded up those grooves and got the backing plate area for the shoes smooth. My grooves were almost holes through the plate and I could see how yours might be hanging up on them, especially if you’ve reused the old shoe springs. A new set of those make a HUGE difference in pulling power. Ask me how I know...😉 I had to replace mine after 500 miles when one broke and made an awful grinding sound in the front drum.

It can’t hurt to weld those grooves up and see what happens. That’s a freebie. Time, yes. Cost, no.

So , did you ever fix the problem. Let us know to help another bolter.

If you adjust the take up on the brake pedal to the master cylinder too much, heat expansion of the metal linkages and brake fluid will cause the brakes to engage. It just happened to me after I replaced the pedal bushings and had to reinstall the linkage. I adjusted it a little too tight and after the 15 minute ride to the feed store, the brakes were dragging on the ride home. It was all 4 corners for me, all the drums were very hot and I could smell burning brakes. I just backed off the pedal adjustment and the problem was gone.
Your issue could be a combination of the pedal adjustment and maybe the shoe adjustment if you're only seeing it on the rear brakes. I'm sure you'll get it after some trial and error. At least that means you get to drive it bunch!

I vote for the master cyl. adjustment. The rod should have a tiny amount of free play before it contacts the piston inn the master cyl or the booster. If not the piston in the MC does not come back far enough to open the port & relieve the pressure.

George