That is the name...or compressor clutch..

but the thinking is - if you coil is bad the compressor is not far behind...that is why you have to buy them as a unit.

Rock Auto has a new aftermarket for 174...I remember paying 99 dollars for clutches before...so you probably will have to buy the while unit. Or, go to the junkyard

 

I tried to find brushes for a starter once, Couldn't find much after searching or would have to buy 40 more than i needed. Seems they don't want to sell individual parts to repair things. I'm sure it's out there but you have to do a relentless search. I wound up going to a guy that rebuilds motors and breathed new life into the starter instead of replacing it.

 

Check eBay for the clutch and coil.