I have an older Chronarch 100 that needs a new bearing on the spool shaft. It was bought new in the mid to late 90's. Not sure if "spool shaft" is what it's called but it's the bearing on the shaft running through the spool.

   Do I just need to remove the pin going through the shaft that keeps the bearing on?

yes , you need to remove the spool shaft retaining pin to remove the bearing . here is the breakdown of a reel , there are photos and explanation of removing the pin correctly , cause if you do it wrong and are not careful you will ruin the spool shaft or the pin . this is a Revo Inshore reel , but it will be generally the same as far as spool shaft pin removals go

http://www.tackletour.net/TTForums/viewtopic.php?f=37&t=29451

TY

Be really careful. it is very easy to bend the spool shaft or damage the spool itself. On the positive side, in my experience, the Shimano pin is much easier to deal with than the Revo.

I have an older Chronarch 100 that needs a new bearing on the spool shaft. It was bought new in the mid to late 90's. Not sure if "spool shaft" is what it's called but it's the bearing on the shaft running through the spool.

Do I just need to remove the pin going through the shaft that keeps the bearing on?

How do you know it needs replaced?

The engagement pin on the Revo is tapered and can only be removed in one direction. While the Shimano engagement pins are straight and can be removed more easily. If you do mess up it will cost you a new spool, be very careful when trying to remove this pin it has gotten many an angler into costly trouble.......

Good Luck & Tight Lines!!   

If I were you I would rather have it done by a pro and while I 'm at it change the other two bearings and change the drag pads. RM or DVT will do a great job.