Since I've owned my jeep I have put new drums, hardware kit, wheel cylinders and lines on the back breaks the shoes still look good. I adjust them to where I can barely get the drum on and they still don't work that good. When I am sliding backward down a muddy hill the front will lock up but the rear won't, even when I mash the pedal to the floor. If I put it on jack stands and put it in gear the wheels do stop when I push the pedal but it seems like they should stop sooner than they do. If I am on a gravel road and hit the brakes the front will lock up but the rear wont lock unless I pull the e-brake.

 

You need to adjust the rear shoes with the drums on, through the little rubber covers on the back. They should be adjusted so they start to drag, then back off a litttle bit. You can't get it tight enough with the drum off.

 

An actual adjusting tool or bent screwdriver really helps with the "back off a little bit" part. Otherwise it can get a bit frustrating.

 

I've successfully adjusted my drums so that is slight drag on them with the drums off. the presence of a rust ridge on the drum will make this impossible though. I'm thinking you may have a failing master cylinder or prop valve.

 

Prop valve?

 

Proportioning valve.