If the brake-shoes are not fully retracting, yur gunna see them not sitting against the top anchors.
Here are la few reasons for this. In order of likelihood;
Mechanical;
1) park brake strut engaged
2) park brake cables not releasing
Hydraulic;
3) fluid not returning to M/C. This can be due to
a) w/c slugs sticking in their bores, or
b) collapsed hoses, or
c) internally rusted brake lines. This usually takes place in the lowest parts of the rear lines, where water collects, like under the driver's seat.
I've never seen it in front disc brakes.
d) compensating port not open. This could be an adjustment if a recent replacement, but on ancient ones, the hole is usually rusted shut. I just drill it out as a matter of course; but don't drill into the seal! You can often tell if the port is closed by the fluid not roiling on pedal release.
Unrelated to brake drag,
is rearend drag or rear wheel-bearing adjustment;
>like as if the axle is allowed to carry the drum into contact with the shoes. or
>If the gear oil is not serving it's secondary function as a coolant anymore and the lash goes away. or
>if the fluid level is too low, and the pinion bearing is going away.
>Don't forget; tapered bearings have to be grease-packed; they do NOT share oil with the differential. Well, they're not supposed to.
BTW,
>if your rear tires are not the same diameter, then differential action is called into play, which will make heat inside the diff. which will go into the oil, then the housing and simultaneously, the axles.
>also
Soft, undersized or overloaded tires, will make plenty of heat due to carcass-flex, some of which goes into the air inside the tires, then into the wheels which are bolted to the axles and drums. Sometimes the tires get so hot that they explode.
