I have a 94 F-250 with heavy duty rear axle. Sometimes while driving slowly, when I step on the brake, I hear a thunk, and the right rear brake grabs and doesn't release. When it does this, if I'm stopped on a slope with the transmission in neutral, the truck will not roll down the slope. The brake seems to release after I drive several yards, or back up a bit. I've replaced the rear shoes, drums, and brake springs, and that seemed to help at first, but now it's doing it again. The cylinders, hoses, rear ABS valve, and master cylinder I replaced about 4 years ago, and there is no leakage from the cylinders.

 

 

You might also want to double check to ensure you didn't put the right brake shoes on backwards. The differences in some brake shoes is so slight it is easy to do and it will give the symptoms you describe.

 

What Dave said. The front shoe braking surface is typically shorter than the rear. I'm no automotive engineer, but I'm sure there's a reason for this. I've driven a LOT of vehicles of a LOT of makes, and ALL of them had shorter shoes in front than in back. VW (the real kind), Ford, Chevy, Jeep (which actually had Ford brake components in 1974). Make sure they're not swapped.

Might check your E-Brake components too, and make sure it's all assembled and hooked up right and the lever was installed correctly on the back shoes. Check the cable as well as all the mechanical components inside the drum. The levers typically don't come on the new shoes and have to be moved over during the brake job. If installed on the wrong side, it could cause some problems with the mechanical push-rod between the shoes.

Next question, is does this happen immediately after the brake swap, or does it take a little while and several stops to start showing up? Sounds like something different mechanically is happening on one wheel, perhaps an adjuster sticking? If the adjuster doesn't keep the bottom of the shoes separated enough, then the top edge may not seat properly in the groove in the wheel cylinder piston. I always take my adjusters completely apart, clean them, then lube with lithium grease and graphite mix to make sure they don't sieze. No short cuts on brakes for me. Won't go is a problem, won't whoa is a MUCH bigger problem.

I had a retainer spring come off one time, and besides the damage done by the spring getting stuck between the shoe and drum, I had some wicked fun getting home with a wheel locking up at random intervals.

 

 

Mine did that same thing... frozen e-brake cable.