blade wont lift

[r doud]

i have a john/deer 420c that i have been working on, motor is running now but the blade wont lift. i have oil up to the line on the dip stick but nothing works. is the pump bad, or is there a screen or filter plunged. has been setting for years, don't know how meany. thanks Bob in chilloquin or

[DukeofDeere]

Good morning,

If the Crawler sat long enough chances are the pump has lost its prime. May have to run for a while to bleed the air out. If it’s cold enough and there’s lots of moisture even water in the tank it won’t do a thing. Usually you can hear the pump or some typical hydraulic noise or hose junk when you move the levers if your pump is moving fluid.

Duke

[Buckhorn]

The pump is supposed to be self priming according to the repair manual. When you accuate the lever, oil pressure opens a check valve and allows oil to flow on that line to the cylinder, and return oil from the cylinder flows back on the other line through the valve and into the tank. When the engine is running oil should be flowing in a loop from the tank, through the pump and back to the tank. I think you need to determine if this is happening. If the oil is flowing, then it's possible the check valves are stuck in the control.

[r doud]

ok thank you Bob in chiloquin or

[shinnery]

You can edit your profile to add your location there. To get to your profile just click on your handle at the top of the page.

[Lavoy]

If there is an air leak in the suction line or fittings it won't prime. Occasionally the woodruff key on the input shaft shears off is another possibility.
Lavoy

[Ray III]

I don't know how cold it is there but ice in the pickup tube and cylinders would cause this problem for me.

[r doud]

i think i have narrowed it down to a sticky spool in the back or the valve. dose any on have a good used four way used valve for sale. thanks Bob