I have a 1960’s Montague 8’ fiberglass rod, and I need to replace the cork handle. This pole breaks down just above the reel. The handle below the reel is wood. Just above the ferrule where the pole separates is cork, and that cork is so old, it is breaking up. How can I change out this cork? It looks like I need to remove the ferrule. How would I do that? Heat to melt the glue? Where would I find new cork? Is there any other way to repair this?

Geoffrey,
Pretty simple.
Disassemble the pole.
Use a pair of slip joint pliers, opened up to the lower part of the pliers so that you simply go round and round with the pliers chewing away the cork.
When all of the cork is gone- use gentle heat - to soften any remaining adhesive left on the rod blank and use a razor knife or similar sharp knife held perpendicular to the blank to scrape off all of the adhesive from the blank. If the paint or finish comes off - where the new cork is going to be located - so much the better. But, do NOT nick the actual fiberglass layup, fiberglass, and resin.

Then, depending on the taper of the rod blank you may find that the location of the cork has a diameter that is the same size or close to the same size as the ferrule.

In any event, if the diameter of the rod blank where the grip goes, is smaller than the ferrule, simply use masking tape to create an arbor that will be the same size as the ferrule. If you are going to use a premade grip, simply use a reamer to ream it to the size of the ferrule if the ferrule is larger than the rod blank at the grip location. If you are going to use individual cork rings and wish to glue each ring in place along with the rest of the unshaped cork rings - ream each one out to the same size as the ferrule, and as needed, use masking tape to create an arbor at the total locations of the rod blank where the new finished cork grip, or the individual cork rings go.

Then, after slipping the premade grip and or individual cork rings over the ferrule, coat the rod blank above and at the desired location for the new grip with epoxy. Slide everything in place and if you are using individual cork rings, also coat the faces of each cork ring and clamp the assembly - to insure a good grip. Or, if working with a premade grip, simply slide the grip in place and then use a rubber band based clamp, to hold the new premade grip tight to the rest of the rod 's handle .

Best wishes.

Buy a new cork grip or make your own, drill the new grip for a diameter that fits over the ferrule, sand down the old grip to that dimeter, slip the new grip over the remnants of the old grip and the ferrule and Bob's your uncle. If you need to turn down the grip, to make it concentric or to shape, put the rod together and have at it.