AUX. HYDRAULIC PRESSURE

[Guest]

I HAVE A SIMPLICITY 7012 WITH A HYDROSTATIC TRANSMISSION AND WOULD LIKE TO KNOW WHAT THE MAXIMUM AUXILLARY HYDRAULIC PRESSURE CAN BE SET TO OR IF IT CANNOT BE CHANGED AT ALL

[dlcentral]

Press in either style hydro is set by relief valves.One for forw.one for rev. They are cartridge type valves,am not sure if press. can be changed? dlc

[Al]

Hi, I believe the aux pressure, if you are meaning the lift and Power steering pressure is the charge pump pressure. This is controlled by a relief valve and pressurizes the drive pump case for the pump to function. This pressure is provided by the little gerotor pump on the left side of the hydro. There is no relief in the drive pump/motor circuit of the hydro. This pressure can be in the neighborhood of 1000 to 2000 lbs at full rpm and the hydro stalled, depending on the amount of internal leakage. It is not usable for anything except to run the hydro motor. When in neutral there is no pressure. When moving the pressure is at the level required to turn the motor against whatever load it is pulling. Without looking it up it seems like the charge pump presure runs about 250 lbs sq in normally. This pressure is what forces the oil into the main pump intake so the pump can be bi-directional. It is also a relatively small pump and this explains the relationship between direction changing and powersteering interaction. Under certain conditions there is too little oil for too many places. My 2 cents worth and its free so value it accordingly. Good luck, Al

[JoeJ]

the relif presure can be changed by replacing the springs inside them with stronger or weeker ones ihcubcadet100@hotmail.com