Brakes? Locking up when I go in reverse

I have a '94 C1500 truck, 5spd Manual, when I started up this morning i began to back up went about 3 feet, and the truck just stopped. I have had this problem, once before, but it didn't completly stop and I could tell that it took force to back the truck down a hill, and would even stop if I was to completely step on the clutch. But back to this morning, after this happened, I figured that just like the first time If I pulled the truck up forward a few feet, what ever was wrong would just correct itself and reverse like normal, but today this was not the case, i pulled up, and I put the truck back in reverse went about maybe half a foot, and it just locked up again, and I tried to force the truck backwards a little, but there was nothing, and I didn't dare put too much force on the transmission. I'm guessing this has something to do with the brakes.

Oh, I don't know if this matters or not, But the truck is RWD, and it does not have ABS.

Did you remove the ABS? My 90 K1500 has ABS on the rears only. Not sure if 94 had in on the fronts or just the rears but it did have ABS from the factory.

It would help to know if one or both of the rears are locking up. The self-adjusters only work in reverse and I suspect one or both of them are sticking causing the rears to lock up.

Also look for any fluid leaking (wheel cylinder or axle seal).

//2000CAYukon

No this truck did not have ABS from the factory, and I believe it is both rear tires but I am not sure.

Had the exact same problem with my '93 CK 1500. Wheel cylinder was leaking, and return springs were weak on shoes. When you back up, they lock into the drum. Time for a rear brake job. I'm pretty sure your truck has RWL ABS, but it shouldn't be a factor.

Roadrunner has it nailed its your rear brakes maybe just a broken spring abs makes no difference it doesnt know whether you are driving forward or backwards