Well, I took 1 apart. Used the grease gun method, worked great. Smoothly pushed it out. I did not see any sign of corrosion in there. Put it all back together and I can use pliers to pull the piston in and out. I did not try pliers before. The rubber seals all look good, no tears, no dryrot.
Sound about right? I'm going to do all the rest and see what happens. A rebuild kit for 1 cylinder is $30.00. I'm leery of spending money on the drum brakes when I can spend $230 and convert them to disc and then they will basically last forever. This 4-wheeler will see very light use.