632 squeals

[CAMelectric]

1982 632. Gas Engine and hydraulics are newer/rebuilt 5 years old as far as I know . It ran great all last year. But after last winter it had an issue all summer. It will run fine, do everything properly for like 30-45 minutes. Then once it gets hot the hydraulics squeal a Little while when i lift, the hotter it gets the more they squeal to a point i don't have any lift pressure. Then i let it cool a few hours and it's fine again. It seems like it's not getting fluid to the main filter or the cooler fins.

 

[Tazza]

With the cab off, is there a square block on the hydraulic pump? if so, there is a hidden filter on the left side behind the middle fitting. Remove the fhose then un-screw the fitting from the block, there should be a filter behind it, almost no owner knows it's even there to replace or clean it.
Hopefully that is your issue, easy and cheap to fix.