looks like it needs a bit of TLC on the rear, are they disk or drums?
if disk the brake could have seized on, check by feeling for heat (don't touch, coz you may burn your hand if it is seized)
if it is a drum brake, the return springs may have become slack and cause the shoes to rub against the drum.
renew the head gasket, easy repair, but you need a torque wrench to correctly tighten down the head.