1) The shaft seal bellows should be replaced in six year intervals as recommended by the manufacturer.
2) NEVER USE SET SCREWS MORE THAN ONCE! Please be sure to never use the same set screw on the shaft twice. There are two set screws in each of the two holes in the stainless steel rotor. One is tightened onto the shaft and the other is tightened onto the first to lock it in place against the shaft. The set screws are made with a cup at the base that compresses into the shaft ensuring a secure grip. This maintenance kit comes with five new set screws included. When re-installing the rotor please use new set screws. In the case that you do not have spare set screws, the set screws in the rotor need to be reversed so there is an unused cup being compressed onto the shaft.
3) This kit would be for Catalina 28s hulls 724 and earlier plus hull 727 that have had a dripless shaft seal installed built before the advent of the fiberglass skeg. If you have a later hull check out full replacement kit #Z2501 and corresponding maintenance kit #Z5250 appropriate for those Catalina 28s.