drum brake problems

[71GMC_3/4T]

I just did mine a couple weeks ago. If you have the screws out of the drums (assuming you have them), you may need to back off the adjusters like FredT says. To do this, you will need a brake adjusting tool and a small long screwdriver. It helps to know what you are dealing with before you start, so try to take off both drums - you may get lucky with one. The other side will be a mirror image. Get a flashlight and look in the hole. You need to push the self adjuster arm away from the toothed adjuster wheel and hold it there. You then need to back off the adjuster wheel by engaging the brake adjuster and turning it with the brake adjuster tool. Try to turn the drum while you are doing this. If it gets tight, you are going the wrong direction. Either that, or try adjusting it without holding the self adjuster arm. It should turn easily only in one direction. Once you have established that, push in on the arm and go the other way.

While you have the rearend apart, it is also a good idea to put new seals in the hubs and repack the bearings. Get a new diff cover gasket and change the oil too. It will thank you for it by lasting longer... Go to Napa for the gasket. Most of the Checker/Autozone type stores around here didn't know jack about 3/4 tons.

If you're going to disassemble and repack the bearings, you will want to buy the nut keepers, which for some reason, Checker's had(!). If you don't have a 1 5/8 socket, you can tap the nuts loose (after bending the keepers out of the way) but use a drift punch instead of a chisel like the previous idiot did on mine.

When I did mine, one drum was well grooved from the rivets and the other was still fair due to being lubricated by gear oil. They told me they were beyond turning, but I asked them to humor me by just smoothing them up and leaving the grooves. It's an old beater and I couldn't see spending another 100 a side on new drums.

Rebuild or replace the brake cylinders while you're doing this.

Good luck!