Lift is either all the way up or all the way down

[baughmama]

Hydro heroes,
Got a '52 that I recently got up and running. The lift arms are either all the way up or down, doesn't matter if it's in draft control or position control. If the handle is up and I start moving it down, after about 2inches of travel then the arms start dropping (which I think is correct) but they go all the way no matter where I stop. Same for going up. Fluid looks good, no water contamination. Lifts strong and stays there so that tells me the pump, cylinder, and piston are fine. I haven't taken the top lid off yet. Am I looking for the springs and linkage to be out of adjustment or should I expect some broken parts? Seems like it's stuck in draft mode but the lever has good spring tension and you can definitely feel it go into place.

Pic is my eldest taking it for a victory lap when we got it going.

 

[JMOR]

Hydro heroes,
Got a '52 that I recently got up and running. The lift arms are either all the way up or down, doesn't matter if it's in draft control or position control. If the handle is up and I start moving it down, after about 2inches of travel then the arms start dropping (which I think is correct) but they go all the way no matter where I stop. Same for going up. Fluid looks good, no water contamination. Lifts strong and stays there so that tells me the pump, cylinder, and piston are fine. I haven't taken the top lid off yet. Am I looking for the springs and linkage to be out of adjustment or should I expect some broken parts? Seems like it's stuck in draft mode but the lever has good spring tension and you can definitely feel it go into place.

Pic is my eldest taking it for a victory lap when we got it going.

Worn cam follower, out of adjustment are suspects

 

[baughmama]

Worn cam follower, out of adjustment are suspects

What are you referring to by "cam follower"?

 

[JMOR]

What are you referring to by "cam follower"?

The pin gets a groove worn into it by the cam & sometimes the cam suffers significant ware, too. This pin is worn almost completely through.

https://imgur.com/4sqmkh3

https://imgur.com/HEyUJYw

 

[baughmama]

The pin gets a groove worn into it by the cam & sometimes the cam suffers significant ware, too. This pin is worn almost completely through.

https://imgur.com/4sqmkh3

https://imgur.com/HEyUJYw

Ah ok. Is that the one that is a little stubborn to get out?

 

[JMOR]

Ah ok. Is that the one that is a little stubborn to get out?

yes

 

[Btzj02]

X2 on the follower pin. My 8N51 had similar symptoms when I bought it. I found that the cotter pin holding the spring behind the control valve, located in the hydraulic pump had failed and there was no spring pushing back on the control valve. The PO had installed a new follower pin but did not inspect the pump while he was in there.

 

[Caryc]

If I remember right, don't try to put a regular dowel pin from a hardware store in it. The pins actually made for that are actually a few thousandths smaller than a regular stock pin.

 

[JMOR]

If I remember right, don't try to put a regular dowel pin from a hardware store in it. The pins actually made for that are actually a few thousandths smaller than a regular stock pin.

The cam follower pin is listed in the parts book as a 5/16 x 7/8 dowel pin but it's NOT. It is a hardened and ground dowel pin that is actually .309" in diameter instead of .3125(5/16). If you try to press a standard hardware store 5/16" dowel pin into your .309" hole, you can cause yourself some major problems. Don't ask me how I know that. The correct pin from New Holland is part number 374072S. ​

The cam follower pin is listed in the parts book as a 5/16 x 7/8 dowel pin but it's NOT. It is a hardened and ground dowel pin that is actually .309" in diameter instead of .3125(5/16). If you try to press a standard hardware store 5/16" dowel pin into your .309" hole, you can cause yourself some major problems. Don't ask me how I know that. The correct pin from New Holland is part number 374072S. The Smiths' 8N page http://www.yesterdaystractors.com/nboard/messages/109032.html - postfp ​

 

[Caryc]

Thanks JMOR, I knew someone would be along that could explain it better than I could. I always wondered why Ford did that. McMaster sells undersized dowel pins but they are still only .002" undersized.

 

[RobFord8n]

Got the same issue on my 8n I think. The cam follower pin isn't as bad as the picture above, but not far off. The cam itself is also worn and has a decent groove in it so it isnt a flat surface. Only have hydrolics working to the highest raised position with the quarant lever all the way up, but won't travel back down at all regardless of position. Not until about after 5 minutes of the tractor shut off it will violently drop all the way down as i suspect the fluid is draining from the piston. I've got it all in alignment with zanes jig so I think I'm good there. Would you all suspect my issue is also the cam follower pin?

 

[RobFord8n]

Anyone think it's the cam follower? Or maybe the piston? I did replace piston with new style with the leather backer. Thanks in advance!

 

[Btzj02]

I few years ago I rebuilt my 8N51 hydraulic pump and the top lid and although I could use the 3 point it drifted all over the place and the draft control would not lift. I followed the videos on Utube when I did all that work. After a few years and a few more tractor projects I decided to go after the top lid again. This time I took my time and used the shop manual. I set everything as the book said and even measured the linkage springs to verify they were the length illustrated in the shop manual. I tweaked one of the linkage springs, found I had destroyed the leather backer ring when installing it the first time and suspect that I had not gotten the control arm seated correctly into hole of the control lever. (I did not drain the oil the second time around but using my fingers as my eyes it felt like I may have stuck the control arm ball between the control valve and the control lever). Today my 3 point operates as designed, even in draft control! It is slower to read and if necessary reread the shop manual to understand how to do things correctly but it will save you a lot of rework. Videos on the web do have their place but unfortunately they can leave out details that may be very important to the success of the project you are working on.