Oops I posted in the lawnmower forum.

First my when mowing my 1989 Simplicity 5212's deck started sounding
like a helicopter. Turns out the outside port mower blade started
spinning freely on the shaft, what looks like a bearing race fell out of
the shaft when I removed the cutting blade, and there is maybe 1/4 inch
play in the bottom of the shaft assembly between parts 10 and 13 below.

Here is an exploded view of what I am talking about from: https://www.partstree.com/parts/simplicity/mowers-lawn-garden-tractor/5212-1691255-simplicity-lawn-tractor-42-deck-12hp-gear/42-48-arbor-group/

I'm pretty sure I'll need part #8, probably 13 and maybe bolts 1 and 11.

I'm stuck though because I can only get about 1/8 turn on bolt #1
using a vice grip on the already stripped shaft and about 18 inches of
wrench. I'm putting way more than 70 lbs of pressure on it.

Think I'll shatter the whole assembly if I try an air compressor?
I'm big and can out torque mine but the hammering effect of the
compressor is worth something.

Thanks in advance for any tips.