Super C Hydraulic Problems

Here’s the latest. Thanks a million Hal

Symptoms:
1) Engine cranks harder then it should. Not bad, but you can tell something is not right.
2) Hydraulic Pump gets VERY hot VERY quick after starting engine (within 15 seconds).
3) Rocker arms don’t move at all.

Purchased a hydraulic pressure gauge 0-3000 psi, 2" hydraulic hose with 1/4" fittings on each end.
Performed the touch-control test procedures precisely IAW the Service Manual with a load of 300 lbs on the rocker arms.

Started the tractor and the pressure pegged my gauge at 3000 psi. Immediately shut off the tractor and cleaned out my shorts! Gauge didn’t break, but I’m sure the calibration is off a little now? I should have been better prepared for this because I noticed the gauge jumping to about 2500 psi while cranking. Hindsight is when I saw that, I should have put on a gauge with a higher psi rating.

Took the load off the rocker arms and restarted the tractor. Hydraulic pressure started at approx 2500 psi then steadily dropped to 475 psi over about a 30 second period. As the pressure dropped you could hear the engine idle increase as it wasn"t laboring as much. Pressure remained at 475 for a little over a minute so I shut her down as the hydraulic pump was smoking hot. IAW the book pressure, without a load on, should be in the 15-40 lb range.

Diagnosis: Faulty safety valve. Hydraulic pump works well.

So I guess my next step is to purchase rebuild parts and proceed with a hydraulic cylinder block rebuild.

I’m open to suggestions if anyone has experience with this.

Thanks;
T.Brown

I have rebuilt two with off the shelf o rings. If relief valve is not working could be broken spring or stuck ball. I found all o rings were shelf items. LOL ud in houston, tx.

That should have zero pressure when not moving.
Your control valves are either out of adjustment, or stuck in the on position. ( the pressure regulator is also stuck ) so do not run it.
Polish things very minimally. 600 grit and do not remove metal, just rust. Jim

The bypass valve for the hydraulic system is located inside the touch control unit. It is designed so that when the rockshaft and the control levers are both in the "same" position the bypass valve releases and there is very little pressure in the system. The oil is just going from the pump to the touch control (bypassed) unit and back to the suction of the pump. It the bypass valve can not pass the oil then the pressure is going to continue to build up. The pump is a gear pump and it will continue to build pressure until something breaks. I would suggest opening up the touch control unit and seeing if something is plugging one of the internal passages.