Bamar In-Mast Furling Halyard Replacement
 

HELP!! Does anyone have any experience with a Bamar in-mast mainsail furling rig? Mine is on a Taswell 43, 22 years old and the wire halyard has never been changed(and it's raw)! I'm doing a complete re-rig, the mast is out of the boat, we're trying to get rid of the wire halyards, and I can not find any way to get access to the upper swivel head or the halyard attach point---except to cut a new "doorway" in the mast!!
Any advise/experineces/and suggestions.....for changing the halyard, maintenance to do, how to dis-assemble the system, and/or things to look for/fix on the rig will be very much appreciated. Somehow cutting a chunk out of the mast just doesn't seem to be a good plan! Thanks in advance.

Bamar info