Rear brake locked up?

[Macs Garage]

(1999 GMC K2500 8 lug 5.7) Went to use the truck and right rear wheel was skipping on road.. If I backed up it was fine, go forward again and still not turning. Went back and forth a few times and it started working. Brakes were replaced last year and don't have many miles on them. Haven't noticed any leaking brake fluid. This is the second time it has happened. Not looking forward to pulling those big drums off. Or is it my rear end? Asking what to be looking for and suggestions.

 

[Schurkey]

You're not going to know until you pull it apart.

Probably grease or brake fluid on the shoes making them grabby. But not guaranteed.
Probably NOT something in the differential, or it'd be goofy backing-up, too.

 

[Erik the Awful]

Probably NOT something in the differential, or it'd be goofy backing-up, too.

A broken-off tooth can get pinched by the gear in one direction, and not in the other. I'd pull the drums and inspect, and if nothing looks out of the ordinary, pull the diff cover off and look for FOD.

 

[Macs Garage]

Update- 14 bolt 9.5" rear end. Hasn't happened again, but crawled under the truck tonight. Found the fill plug on the cover is homemade. Always has had old oil around it, but now is wet and the bottom of the cover is wet also. I added 20oz of 80/90. I will be ordering a new cover and putting new oil in. Pulling the truck wheel off and checking the brakes is on the to do list. I can hardly keep up with the honey do list.

 

[GoToGuy]

Home made plug? Wow that's sad.
My first guess would have been look for something in the Rt. Brake torquing over something braking locking the wheel. As diff problem most likely would felt and sounded like a rock crusher. Yep the only to tell is open it up. Inspect and evaluate. Good luck.

 

[Erik the Awful]

You were under the truck but didn't bother to pull the rear cover and inspect? It's quite literally a fifteen minute job, and that's if you're slow at putting puckey back on the cover.

 

[Macs Garage]

I want to replace the cover. So why take it off now? New one on order with the fill plug. Out of stock most places.

 

[Erik the Awful]

So why take it off now?

Went to use the truck and right rear wheel was skipping on road.. If I backed up it was fine, go forward again and still not turning. Went back and forth a few times and it started working.

So far you've been lucky. It truly sounds like you have something loose in the rear. Next time it moves around you may break something serious.

 

[Macs Garage]

Pulled the brake drum off last night. Was dry inside and but the rear shoe was sticky on the bottom 3" and front a little bit. Otherwise everything looked normal. After cleaning everything off and the brake cleaner evaporated, the rear side of the wheel cylinder was a little wet. I replaced the wheel cylinder and twisted the brake line off in the process. Made a new brake line, new brake lines were on my list anyhow so I had the supplies. Revisited the rear end and the bottom bolts on the cover weren't very tight. Hopefully my new cover will arrive before UPS goes on strike.

 

[Macs Garage]

So far you've been lucky. It truly sounds like you have something loose in the rear. Next time it moves around you may break something serious.

Walmart was out of 80/90 and the parts stores were closed.