I had my shaft break on me twice in a row. Then took it to Clear Star and they really know what they are doing with the AC System.
My issue was the other two well well known shops were setting the belt tension way too high and this pre loaded the shaft. The first shock it gets it just snaps. They set the belt tension and I’ve not had a problem since. Blows nice and cold.
There are a few other things to check but my bet is on that.
They set the belt tension with an old spring type fish scale. They pad the top rod and push on the belt and measure the pressure it takes to deflect the belt a certain distance and set the pressure. I thought I wrote down the specs they use but can’t find them. From memory it’s around 8 pounds for 1cm deflection. Mine was at 14.
Cant remember if it was 1cm or 1/2 cm deflection. If your close to Clear Star in Dallas just take it there.