Questions:
- you hear a squeal when you brake, but only after you've been driving around for 1/2 hour or so?
- you assume or your know the shoes and/or drum is hot - because you hear a squeal? Or -
- you have somehow measured the drum / shoe temperature and compared it to the other side?
- do you know if the problem side is dragging? Because you've jacked up that tire, put it in neutral, and have problems turning the tire by hand?
- when this problem (heat condition) is happening, does that tire lock up significantly sooner than the other tires upon moderate to hard braking from speed?
I assume your rear brakes have the star wheel adjuster mechanism, to advance the shoes towards the drum as they wear. Here's a theory: Your adjuster has positioned your shoes, when cold, to a satisfactory position with respect to the drum (a satisfactory gap). But as you drive and brake, your shoes heat up (which is normal) but the gap closes up and your shoes are touching the drum when they shouldn't be. As a test, configure that wheel for manual adjustment - take the wire off and put a spring across the adjuster wheel (remove the wire and the adjuster plate). I believe I've read where police cars with 3" rear shoes have this setup - the manual adjuster setup. Back off the adjuster wheel so that the drum spins freely when cold, so there's a good gap between the shoes and drum, then drive and see how that goes.
> In the photo, you shoes appear to be wearing unevenly, more at the bottom.
The brake shoes will float and will find their optimal position when applied, I can't see how a wear pattern could develop based on an off-set wheel bearing. Perhaps brake shoes that are extra wide, like the 3" shoes, don't have a stiff-enough backing plate, and most of the wear will be along the center spine (because that's where the piston is pushing).
Check that the shoes are correctly mounted - the shoe with less braking material is mounted on the forward-facing side of the wheel.
Alternate theory: There is junk in the brake distribution block acting like a 1-way valve. You apply the brakes, fluid moves towards the wheel cylinders, you take you foot off, the fluid is supposed to flow back, but in the rear distribution block the channel for that wheel has junk that plugs a passage and pressure is maintained in that wheel cylinder. The junk being particles of the inside of the rear flex brake hose. Take that block off, blow air through it, look at the ports under a magnifier, pic at them with a needle or pass a wire through them, wash the block in solvent.
