OK, so you have cartrdge pins. Are you planning on re-using them or simply replacing the pins & collets with new.?
Attached the R&I procedure but if it has been on for any length of time it will not be as simple as the procedure makes out so prepare yourself for a challenge. To give you an idea the 4C-9634 Puller Stud is rated at 60 tons, the 6V-3175 puller is rated 55 tons @ 10,000psi. For your own safety please don't go using 1-1/4" diameter 12TPI all-thread bar, it WILL break.
For unlawful carnal knowledge?
There is a good reason why the recommended tooling for removing the collets includes a 55-ton rated hydraulic cylinder……I've tried a treaded puller on them with no luck. I think I finally torched the collet out but don't really remember. I know I spent several days fighting it. The ones on a 973 have three fine thread holes to use bolts in. Did one in around 4 hours last week. I would get new ones with the new pin.Good luck.