if the brake lining is cracked all the way through (or even more than just a heat crack) just replace them. the price of rear brake shoes is not worth the sudden failure if the shoes come apart (brake lockup or worse, no brakes at all)
replaced the worn out wheel cylinders then drive it. if it is not ok then adjust the proportioning valve as needed.

85 runner -dual cases, headlight harness, 34" TSL's
86 toy buggy getting sas'ed with a 14 bolt rear - 8.5" 10 bolt front (this will go away when i find a 60)