I had the same issues with my AC on a 7130. Replaced the AC belt and it started squealing again not long after it was replaced. Found out that the drive pulley is stamped steel and wore enough that the AC belt would bottom and slip. Replaced the pulley with a newer heavier pulley and the problem went away.

It was a son-of-a-gun to get those four bolts out of the fan hub though. I finally had to torch two of them and use vise grips to remove them. Make sure you protect your radiator if you do any torching.

On the 3pt arms....mine started coming down, so I just made a couple of brackets that slip around the lift assist cylinders and keep the arms in the upright position. *shrug* Poor man's way of fixing the issue?