I have a piece of equipment that's homemade and recently I've started having a problem with the hydraulic system. Under a heavy load or when a cylinder maxes out, it has started loudly squealing. It used to be pretty much quiet. I thought it might be the pressure relief and changed it, but it made no noticeable difference. I tightened the belt and keep the filters changed, but nothing has helped. Can someone point me to what might be going wrong? It worked for a few years just fine until recently. It's a pretty basic system: open center, 20 gpm rexroth pump with a clutch that flows through a series of valves that operate several cylinders and a hydraulic motor. Thanks,
Justin
Justin