[tcoop]

I have a 1984 C10 and have been dealing with the rear brakes locking up. I thought I had it fixed because I have been driving it for a couple months with no problem, but the other day I had to hit the brake hard and the right rear locked. I have changed shoes, both rear wheel cylinders, had both drums turned twice, new master cylinder, flushed the lines and adjusted and re-adjusted the brakes and it will still lock up.
I don't know what to look for as far has wear on the shoes, is there some wear pattern that will give me and idea of what is wrong?
Thanks for the help,

[KMatch]

Only the usual thoughts come to mind, all important: Adjustment must be right, the short shoe must be in front, all air must be bled, the right wheel cylinders from side to side...

How about the front brakes? If they're weak, they'll put more need for the rear to stop it.

Does it have a rear bumper? Any other loss of rear weight?

More weight in the front as in brush guard?

[tcoop]

Originally Posted by KMatch

Only the usual thoughts come to mind, all important: Adjustment must be right, the short shoe must be in front, all air must be bled, the right wheel cylinders from side to side...

How about the front brakes? If they're weak, they'll put more need for the rear to stop it.

Does it have a rear bumper? Any other loss of rear weight?

More weight in the front as in brush guard?

I have adjusted them several times and even tried letting the self-adjusters adjust them. The shoes are installed correctly as well as the wheel cylinders.
I can only check the front brakes by applying them hard and the truck goes down in the front, so I assumed they were working correctly.
I have all the stock bumpers and no extra weight on the truck.

I noticed one shoe has a shiny area in the middle of the shoe. Now I am thinking that if that area is hitting first it would add more pressure to that area thus stopping it quicker that the rest of the brake system? Does that make since? Would that cause the rest of the brake system from being able to be applied further? I ask that because when the brake locks, it seems that is all the braking power I have and that isn't very much.
Could that be faulty new shoes or maybe warped drums? Hummmmm
Thanks for the suggestions,,advice is always welcome,
oletrkguy in SC

[ken konoff]

tcoop, I also have owned an 1984 C-10 for 22 years, have had the same problem when making a panic stop of usually right rear locking up. I have found after all these years what compounds the problem is if the brake drum lining is worn, or too thin the rear brakes lock up more often. Hope this might help another 84 C-10 owner. Ken

[tcoop]

Originally Posted by ken konoff

tcoop, I also have owned an 1984 C-10 for 22 years, have had the same problem when making a panic stop of usually right rear locking up. I have found after all these years what compounds the problem is if the brake drum lining is worn, or too thin the rear brakes lock up more often. Hope this might help another 84 C-10 owner. Ken

Did your truck have this problem the entire time you owned it, or did it start happening as the drums worn.

Actually, after you said that, I noticed that after I had the drums turned, it would do ok for awhile, but eventually they would start locking up again.

Did you eventually get your problem corrected?
Thanks,,,

[ken konoff]

Yes, I still own the truck, never will sell it, and I bought new G.M. drums big bucks, and with the new drums and new pads seemed to correct the locking up problem. I also found too much brake pad dust compounds the problem also. I currently don't put too many miles a year on the truck, 2,000 to 4,000 miles a year, so the former problem doesn't really have a chance to appear. I clean the rear brake assembly every year, doesn't take very long. When I ran cheap Chinese drums, they seemed to wear alot quicker. Hope this help's. Ken

[tcoop]

Originally Posted by ken konoff

Yes, I still own the truck, never will sell it, and I bought new G.M. drums big bucks, and with the new drums and new pads seemed to correct the locking up problem. I also found too much brake pad dust compounds the problem also. I currently don't put too many miles a year on the truck, 2,000 to 4,000 miles a year, so the former problem doesn't really have a chance to appear. I clean the rear brake assembly every year, doesn't take very long. When I ran cheap Chinese drums, they seemed to wear alot quicker. Hope this help's. Ken

Yes it does help, I have been leaning towards getting new drums. I need to do something because I want to use this truck to pull and more importanly stop my boat. As it stands right now I am a little gun shy about pulling anything. Thanks for the feed back, I appreciate it

[66GMC]

Rear axle seals are in good shape ... no oil contamination, right?

We used to have a 95 Ford Ranger that would lock up and /or drag the rear brakes when it was damp out. Stepping on the park brake part-way for a few seconds was usually enough to dry things out.

[sqzbox]

2 things you can do.

1. convert to a disc brake rear Axel
2. change the rear gears to a posi.

Open spools are famous for locking up the right rear under panic stops. If you already have a posi in it, the drums are probably your problem.

I don't see how you got both drums turned twice and still be within spec's for drum face thickness. The spec's for the thickness is stamped on the outer edge of the drum and anything thinner is shot! You could do better buying new drums as mentioned.

[tcoop]

Originally Posted by sqzbox

2 things you can do.

1. convert to a disc brake rear Axel
2. change the rear gears to a posi.

Open spools are famous for locking up the right rear under panic stops. If you already have a posi in it, the drums are probably your problem.

I don't see how you got both drums turned twice and still be within spec's for drum face thickness. The spec's for the thickness is stamped on the outer edge of the drum and anything thinner is shot! You could do better buying new drums as mentioned.

You may be right because when I look at the drum is looks like the inside of the drum it shiny and the outside of the drum doesn't look like it it hitting.
thanks

[fast68]

backing plate may be tweaked damaged

are the shoes on right?

primary and secondary not reversed?

springs all on in correct order?

parking brake parts not binding or installed right?

try removing the parking brake cross bar and arm lever and such


if there is any fluid or oil at all on the drum or shoes then it will cause freezing grabbing

definitely!

gotta be clean and dry

[tcoop]

Originally Posted by fast68

backing plate may be tweaked damaged

are the shoes on right?

primary and secondary not reversed?

springs all on in correct order?

parking brake parts not binding or installed right?

try removing the parking brake cross bar and arm lever and such


if there is any fluid or oil at all on the drum or shoes then it will cause freezing grabbing

definitely!

gotta be clean and dry

Everything you mentioned is correct. The shoes are on properly and there are no leaks, everything is dry.
I have not taken the parking brake bar out, but almost everything else i have tried. Only thing i haven't replaced on the rear brakes is the drums and those may be next. I am running out of options....thanks for the help