I recently purchased an old 99H. It's been setting for about 5 years or so. I'm trying to get it loaded so I can haul it home. I got the engine running and attempted to raise the blade. The hydraulics responded for a second or two and then stopped working. My pressure gauge on the valve block showed 400 psi. I shut it down, checked a few things, added a little more fluid, and restarted. Pressure went up to 800 psi. Still no response from the hydraulics. Then fluid began pouring from the top seals of each of the 8 control valves. By chance, does anyone know what approximate pressure range I should be seeing from this system? I don't currently have a manual for it. It's a 1947 model.
The main reliefs should be set at 1500 psi. If you have tiller bar steering, you have a 25 gpm pump and one relief valve. If you have orbitrol (steering wheel) steering, you have a 38 gpm pump and 2 relief valves.
Thanks. I located an adjustable valve (appears to screw in and out like a regulator) back by the pump. It was maxed out clockwise. If it works similar to a pneumatic regulator, that position should be fully open. It's starting to sound like a pump issue, but I hope not. It worked fine when it was parked. Also, if I'm able to fix the pressure problem, I'm likely to need seal kits for the control valves. I don't see any identification on them except "PG" stamped in the end caps. Peabody-Galion perhaps?
The original valve banks on these machines were made by Austin_Western. The OEM parts source is: http://www.minnpar.com/