I've used PB Blaster, WD-40 and Kroil. Found a product that I found beats them all. Deep Creep by Sea Foam. This stuff will break loose rust, carbon, tarnish and even stuck on 216 cu.in. vibration dampers. It also leaves a rust inhibitor coating on the metal! Was also able to get a Gravely 44Z riding mower drive pulley loose from the crankshaft that had so much rust around it and in between the pulley and shaft that it was almost rust welded to the crankshaft. Deep Creep and a few passes with a propane torch and it came loose. Just another suggestion....
Tim
