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cs
08-25-2010, 01:33 PM
One of the problems with old work trucks is that they don't get driven enough. Mine didn't get driven hardly at all while I was gone. I've been driving it some since I came home and have noticted it now has a problem. BTW this is a '92 short wheel based 4-wheel drive Chevy truck with a manual transmission.

The problem is going in reverse. When going in reverse the right rear wheel locks up. This only happens in reverse and only on the right side. Now if you drive it a mile or so forward than there is no problem backing up (i.e. the back wheel doesn't lock up). But park it for a little while and when you go to back up the right rear wheel locks up. Drive it around the block a time or two and it clears up.

I'm thinking that I need to re-build the rear brakes.

Any other suggestions?

Chad

Bobby of Tulsa
08-25-2010, 01:53 PM
Pull that right rear drum and see if the shoes are wet. Sometimes a wheel cylinder will begin to leak, and the shoes will swell up.

Hwyl
08-25-2010, 01:58 PM
Fix it ASAP, or you'll be looking at a new drum.

Uncle Duke
08-25-2010, 02:30 PM
Is it locked up as soon as you go into reverse and start moving? Or as soon as you hit the brakes in reverse?
Some drum-rear setups have an adjuster which operates when you're backing up and hit the brakes - that might be sticky.....

cs
08-25-2010, 02:38 PM
It locks up after about 10' without hitting the brake. Sometimes it is more than 10' and sometimes it is less. I do know that driving forward a little while takes care of it. It may be a broken spring or a bad wheel cylinder. I'm going to have to take it down and look at it. I've even heard of rubber hoses colaspsing causing this problem.

BTW it is not driven enough to make this an ASAP problem. By not enough it is only driven when needing to haul something and right now I have nothing to haul. The other times it is driven is when I have to move it to cut grass.

Chad

OconeePirate
08-25-2010, 03:23 PM
I'm going to venture a guess that Uncle Duke there is right. My poor little Ram 50 did the same thing. Clean the adjusters and other mechanical bits inside the brake drum, see if that fixes it.

Mike DeHart
08-25-2010, 03:39 PM
You could have rust in the wheel cylinder on that side causing the brake shoes to not retract all the way. When everything is cold it will self apply because the shoes are dragging. Drum brakes are designed so they do not self apply going forward, which would be a bad thing when all four wheels locked up every time you stepped on the pedal. Anyway, they still drag going forward, you just don't notice it, until the drum heats up and expands. The expanded drum then does not lock going backward because the shoe isn't dragging anymore. Except that when it cools down you get the same thing all over again.

It could also be a wet brake shoe from a leaking cylinder as said above. Either way, I would figure on replacing both rear wheel cylinders and likely both rear shoe sets. Have both drums resurfaced since the heat might have warped the one, and whatever you do to one side you always want to do the same on the other. Suck the old brake fluid out of the master cylinder, refill it with new and bleed the entire system. Old brake fluid absorbs water and rusts cylinders, especially when the vehicle has been sitting.

cs
08-25-2010, 05:17 PM
I'm hoping that maybe this weekend I can get a chance to tear the rear brakes down and try and see what it up.

Chad

Stiletto
08-25-2010, 08:30 PM
I wonder if the chamfer on one of the brake shoes is worn away and the leading edge is picking up on the drum.

Dumah
08-27-2010, 10:21 AM
Strongly suggest a complete teardown of the rear brakes and pay particular attention to the return springs. When I replace shoes on a drum brake setup, I ALWAYS replace the "hardware kit", this will give you not only springs but retaining hardware as well. A common problem with vehivles that sit a lot is the holddowns breaking and causing similar grief.

Cheers, Dumah
Halifax, NS