The problem(as stated by several purchasers) was that some of his MC's had no recess inside the piston on the back side for that $1.00 neoprene retainer to lock into. In other words the piston in the back was for a power brake setup rather than a manual brake one. this summer I am going to(on the bench ) use some RTV & let it set up & see whats up with this. It does sound hokey(& unsafe ) but I've always(& still do) greatly respected Ebergs knowhow so I am going to cut to the chase & see for myself