I contacted the Axle manufacturer and they sent me all new calipers
the calipers on your MasterCraft trailer are from an early GM design. The manufacturer is Reliable Tool & Machine in Kendallville, IN., they sell the complete axle to masterCraft. They are perfectly aware of the problem of sticky pistons due to incorrect tolerances of the caliper bore and piston and should be giving you free replacements calipers. You can contact them @ 260-347-4000 or www.reliabletool.com
, the man in charge is Kelly Charles.