90's Backhoe, lightly used.
All other hydraulics seem to work fine, but the boom lift cylinders suddenly barely have any oomph.
If the arm is even half extended, they can't even lift the boom.
How do I tell if this is a cylinder/piston leak? Or spool valve problem? Or maybe bleed or fluid problem. Need higher weight oil?
Using Valvoline AW32 hyd fluid now (100F here, too)