[1976gmc20]

Well, just to add to the above: if any oil is getting past the cylinder packing, then it is getting routed into the second hydraulic tank when the cylinder is fully extended, and then it is going - well, apparently nowhere but rather just filling up that tank. That could cause problems, and also if that tank is not vented so the cylinders can suck air or oil back when retracted/lowered.

I'm going to guess there is a plug in the bottom of that round tank that previously or at least by design would have had a suction line leading directly to a PTO driven pump. It was common to use the non-pressurized side of double acting cylinders to store extra oil so the tank could be smaller. It seems like at the very least there should be a cross-feed line between the round tank and the pump/tank to equalize the oil or air coming out of the "top" of the cylinders.


I used to use black pipe for static portions of the high pressure side of the pump without any problems, but I reckon that's no guarantee that it is truly safe. I had if I recall correctly a 20 gpm pump that could produce up to 2000 psi. I had plenty of hoses blow out before I finally managed to replace everything with brand new hose, but the steel pipe never failed.