Erratic hydraulic lift operation

[JDunk]

I have a '52 model TO30 that runs like a top, but the hydraulic lift has issues. First, the lift handle is way out of whack in the quadrant. It begins to lift about 2 1/2 from the bottom. From that position to the top it's really not doing anything. When I have a heavier implement like my bushhog or disk attached and pull the hand lever up the lift will raise all the way up quickly and then immediately drift back down, once it drifts down it will lift all the way back up and repeat the process of drifting down.

If I raise the lift handle slowly and stop it 2 1/2 or so inches from the bottom it will lift the implement and hold its position. Lowering the implement is kind of an all or nothing proposition. I can ease down on the handle about an 3/4 inch and it creeps down excruciatingly slowly, but if I take the handle down farther it slams down all at once.

Any ideas/help would be greatly appreciated. I have a shop manual but it doesn't really address this particular situation. I have adjusted the lift spring according to the manual, but nothing I've done with it will get the lift quadrant anywhere near the way it's supposed to be. The manual states the lift handle all the way up should be in the transport position and it should begin to lower about 2 1/2 inches from the top. All my lifting is happening in the lower fourth of the handle quadrant.

 

[Jerry/MT]

You may need some adjustment to the lift lever. The neutral point should be 2-1/2 inches from the top. Below that point the lift linkage should start to uncover the exhaust port and the lift should slowly go down. If you move the lever all the way down, the lift will rapidly drop. The properly adjusted linkage should start to lift when the lever goes above the neutral point rising the fastest when you lift it all the way back. At the neutral point the lift should hold.

The Ferguson Shop Manual (~$20)has instructions for adjusting as does the Owners Manual.

You set the control spring with an implement on the lift raised all the way up so you can just rotate the control spring by hand.

Mark the quadrant at the 2-1/2 inch position from the top and loosen the the 4 cap screws on the quadrant. Move the quadrant assembly full back and set the lever to the mark.

Tighten the cap screws snug but loose enough so you can pry the quadrandrat forweward.Pry it forward til the lift starts to drop. At that point, fully tighten the cap screws without moving the quadrant.
If you still have a drift down problem then I would suspect a leak in the lift cylinder or the stand pipe.
John(UK) can send you these instructions if you ask him.

 

[Jerry/MT]

Some of the erratic operation could be caused by a sticking control valve. The other thing you might want to do is to open the right hand side access panel and make sure the linkage is all hooked up properly.

 

[John(UK)]

You have a leak on the system and it is working correctly.When the 3 point reaches the top of the lift cycle it stops pumping, but because of the leak it is dropping and so the Pump lifts it again back to transport height. It will keep doing this until the leak is stopped and it will prevent any leak down..The Quadrant Lever adjustment that you mention, it is possibly out of adjustment too but you can only adjust this correctly when the leak is stopped and the Draft Control Spring at the back of the seat is correctly adjusted. If you want the information about how to diagnose and correct the problem, email me and I will send it to you.If you email just tell me again what it is happening to save me searching as I am getting lazy in my old age..John(UK)[email protected]