Does your mast have a "cap piece?" that is a whole casting that is mounted on top of the mast tube and contains the various sheaves for your halyards.
- - If so there is normally a large stainless pin that goes through the masthead cap and the sheave. There are sometimes cotter pins holding the Pin from coming out. If so, remove one or both of the cotter pins and use a socket wrench extension bar or similar type round bar to pound the pin out of the masthead cap.
- - If the sheave is mounted in a slot/hole cut into the face of the mast tube then there is normally a stainless steel
metal "box" (sometimes a whole casting) that is bolted/riveted to the face of the mast tube. The box holds the sheave and its mounting pin/arbor. You remove the bolts/rivets and pry the whole box containing the sheave from the mast tube. Then disassemble the sheave and repair or replace it.
- - On the bulk of boats the masthead halyard sheaves are metal with a "oilite" bearing. This is a solid bronze short length of tube which has been impregnated with oil
and is the "bearing" that the sheave rotates on the pin/arbor. It is normal for these "oilite" bearings to loose their impregnated oil
and then bind or freeze on the pin. After you get the sheave out you can have a new oilite bearing press-fit into it - or - find a "ball-bearing" sheave of the same size - diameter, width, arbor hole - and use it instead of an oilite bearing sheave. I did that on my primary halyard sheaves for the main and jib
- - Basically remove the whole sheave from the masthead cap piece by pounding out the bearing pin or removing the whole sheave mounting box from the mast tube face is the normal process. Then repair or replace the binding sheave.