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Many Farmall Hs came equipped with the hydraulic "Lift-All" pumps. Lift-all pumps of early manufacture were set to kick off at 450 to 500 pounds pressure in the system. Later Lift-Alls are set to kick off at 750 to 800 pounds pressure. These higher pressure units can be identified by a yellow figure 8 painted on the outside of the reservoir. At the time the kick-off pressure was increased, an improvement package (15261-E) was also made available which permitted increasing the kick-off pressure of the earlier pumps. If an improvement package is installed on a low pressure pump and the pump does not have the ability to pump pressure up to 750 to 800 pounds it may be due to a clearance of over .005 inches between gears, pump cover, and back plate. On the earlier pumps, a clearance of .007 inches was permissible; then when the pressures were increased, it was necessary to decrease this clearance to .005 inches maximum. Where the increased clearance is found, it will be necessary to either grind down the sides of the pump body or to replace pump parts. The oil capacity of the Lift-All is 6 quarts (non-detergent SAE 30 motor oil, NOT hydraulic oil). Specifications
Testing Lift-All on TractorYou'll need a hydraulic pressure gauge. Disconnect the hose from the outlet elbow at the pump unit and install a 1/2 inch service tee between the elbow and hose fitting. A 1/2 to 1/4 inch reducing sleeve is necessary to install the gauge into the tee. Start the tractor engine. If the oil in the Lift-All is thick and cold, you need to first warm the oil. Warm the oil by pulling the control rod all the way back to the raised position while the tractor engine is running. Hold it there for only a few seconds and then move the rod ahead to the neutral position. Repeat this procedure until the oil is warm. Never operate the Lift-All under high pressure continuously for more than a few seconds at one time when the oil is cold and thick or it may damage the pump. Throttle the engine down to the lowest idle speed. Pull the Lift-All control rod all the way back and hold it there. Note the oil pressure reading on the gauge when power cylinders are at the end of their strokes. If the pressure reading is 750 pound or higher, the pump is in good condition. If the pressure is lower, it may be caused by any one of the following:
Move the Lift-All control rod all the way forward and allow the implement sections to lower and the piston rods to move into the power cylinders. Speed up the tractor engine and again pull all the way back on the control rod, but this time let go of the rod. If the control rod does not remain in the lifting position when released, this is an indication that the locking device either is not engaging properly, or has been worn to such an extent that the steps on the locking lever will not engage the control lever. In some cases the relief valve piston may be found to be sticking in its expanded position, which will hold the locking device from engaging. With the control lever pulled back in the lifting position, and upon completing the lifting operation, the control lever should move to the neutral position automatically. Note the gauge reading when the control rod automatically moves to neutral, this should be 750 to 800 pounds. If the reading is lower than 750 pounds when the control rod trips, the cause may be:
Allow the control rod to set in the neutral position. If the implement sections drop slowly it is an indication that the check valves leak.. A leaky power cylinder piston will also cause the implement section to drop slowly, however this leakage can be detected by leakage of oil out of the open end of the piston rod guide. Check all pipe and hose connections for oil leaks. Use permatex on threaded connections. This information extracted from the Blue Ribbon Service Training Course, Manual No. 9, "Hydraulic Lift-All for Farmalls H, HV, M, MV, MD, and MDV". |
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