The problem with these brakes is that the main part of the caliper cannot be stripped down. There are three concentric shafts all moving independantly and its almost imposible to grease them properly as they don't have much of a stroke to work the grease in. So far these bits have stayed reasonably free. If they stick I'll have to drill out the welded pins to break it apart,
The auto reverser shoe, toggle arm and centre shaft have large areas of flat steel touching with very little play. They jam up very easily despite me giving the whole trailer a good wash after each dunking.
Still better than drums especially since the bearings do not need to be exposed to access the brakes - and the caliper comes off easily for some "attention" in the vice.