Ever had self adjusting brakes overtighten?

rustycowll69 said
when you say you replaced the back lineS, I take it you mean the hard lines on the axle housing. But what about the rubber flex line from frame to axle tee fitting?. Those can deteriorate internally and act like a one way check valve. It usually happens at a strain point. I've never seen it on a rear axle flex line, but I've seen it twice on front brakes on Darts about 20-25 yrs old. Your Duster is almost 50yrs old.

Congrats rustycow.... I think you hit the nail on the head. I replaced the rear hose this evening and cut the old hose apart. The old hose that I said “looks healthy” had a blockage. I couldn’t blow air thru the hose. I’ll add a photo showing the blocked section of hose. I’m guessing there was probably a small piece of trash that caught in the narrowed section. View attachment 1715473404