You are going to be beating your head against a wall trying to fix that.... I repaired 4 today....along with a body swap and a Blade 350 antenna upgrade.
There are so many things that you need to be concerned with that you will need to work on them for several weeks straight before you can successfully make it work like new again.
The bearings cant be binding, the shafts cant be bent, the axis need to be aligned, the connectors need to be seated properly, motor shaft potentiometer clearances need to be set, this is just a few concerns and the list goes on and on.
The shaft is designed to spin and has to be secured to the roll assembly. If the hole is reamed too large the redloctite will not fill the gap and set up. You will need to bush it with a brass bushing after drilling it out oversize. JB weld is too soft for reliable retention.
Jeremy James