3-Point Hitch Ford 1700 lift arms do not lift

[oracle of ferndale]

I've read the other posts on this topic. I changed the seals on the piston and tried adjusting the position control link. The pump makes hydraulic pressure. When I move the lever for the auxiliary rear hydraulics, fluid shoots 20 feet out of a hole in the line. When I move the lift control lever for the 3ph, nothing happens. No noise, no vibration, lift arms do not budge. I'm looking for some advice before I start taking the lift arm housing apart, or pay someone to do the repair. I have 2 questions, but maybe someone in the forum can ask and answer a better question.

1) My tractor has auxiliary hydraulics in the rear. They are attached to the relief valve assembly under the seat. In figure 263 from the shop manual, my relief valve assembly looks like the top image, when the 1700 model should have the bottom image. Could this be causing a problem or require a different approach to repair?

2) Could the control lever linkage have detached from the lever? I'm thinking about the parts in the red circle in this image.

What else could be wrong? When it stopped working, I was trying to dump some trash out of a small trailer by raising the 3ph and jerking the tractor back and forth. Some of the other posts on topic suggest this was a bad idea and could have caused the lift to fail, but adjusting the position control link should have fixed this issue (right?). This machine is new to me and I could be missing something obvious.

Thanks in advance for any suggestions.

 

[oracle of ferndale]

I checked the control lever linkage and it works fine.

 

[Tinhack]

Doesn't that flow control knob control whether pressure is routed to the lift or to the external valve? ("F" in your second image.) I'm not familiar with the 1700 but I just added remotes to my 3910. The control valve I got with the kit allows full pressure to the lift, partial pressure to the lift and partial pressure to the remotes or full pressure to the remotes. The choice is made my adjusting the single screw valve on the control valve body.

It sounds to me your control valve is adjusted to route all pressure to your remotes. :confused3:

 

[oracle of ferndale]

Thanks Tinhack. This makes sense, but I'm not sure how to fix it. I have tried adjusting that knob and nothing changes. Could the knob be defective? How would I test it?

 

[Tinhack]

With the valve turned all the way in (closed), pressure should be routed to the lift. As the valve is opened, more and more pressure is routed to the remotes. I'm just describing how mine works. That knob may not be turning the valve. (Spinning on the shaft, maybe.) That's where I would focus my interest. I'm not sure how you would test it. Perhaps remove the knob and turn the valve by other means.

I'm saying pressure but I think the correct term would be flow.

 

[oracle of ferndale]

Update. The unload valve was stuck. I popped it out with a screwdriver and oiled the inside. 3ph lift works as it should.

 

[Tinhack]

Thank you for returning and posting the update. However simple the fix may be, your post could help hundreds more TBN fellows.

Glad you got it resolved. :drink: