Top Link Question

lama

New User
I am new to tractors so its possible I am just ignorant. I have tried searching but I have been unable to find anything.

I have an old 2N that I got for free because the previous owner was just going to let it rot in the woods. I have fixed up and have it mostly working. However, when I hook up my bush hog it wont raise up.

It has plenty of power and holds (150 lbs up for over 48 hours) as I replaced the Ram cylinder and Piston. The issue is the top link if it is not hooked up the tractor will lift almost anything but when hooked up a slight tug on it (away from the rear of the tractor) and the arms drop to the bottom. So when it tries to lift the implement it goes up a couple of inches until the front of the bush hog leaves the ground, that puts weight on the top link and it drops back down. Rinse and repeat once the bush hog hits the ground again.

There must be a solution, maybe I put something back together wrong, but I can't figure out what it is. I am hoping someone that knows more about these tractors (or just tractors in general maybe) can help me.

Learning as I go trying not to let a piece of history die.
 
" I replaced the Ram cylinder and Piston"

It's possible, but unlikely that you screwed up the draft control in the process. I say unlikely because that's linkage and replacing the ram cylinder doesn't involve messing w/ the linkage.

Until JMOR or other hydraulic gurus stop by, my only suggestion is to get out your MPC and try and get a good understanding of how that linkage under the top cover works.
75 Tips
 
Touch control lever attaches with 4 bolts in slotted holes, thus allowing adjustment by sliding fore/aft. Loosen and try it slipped a bit more toward the rear of tractor.
 
(quoted from post at 12:49:50 05/04/18) Touch control lever attaches with 4 bolts in slotted holes, thus allowing adjustment by sliding fore/aft. Loosen and try it slipped a bit more toward the rear of tractor.

I have made this adjustment but it rained all afternoon so I have been unable to test it out yet.

Any chance there is a relatively simple explanation of why this works?
 
(quoted from post at 23:35:29 05/04/18)
(quoted from post at 12:49:50 05/04/18) Touch control lever attaches with 4 bolts in slotted holes, thus allowing adjustment by sliding fore/aft. Loosen and try it slipped a bit more toward the rear of tractor.

I have made this adjustment but it rained all afternoon so I have been unable to test it out yet.

Any chance there is a relatively simple explanation of why this works?
hen men build machines, there are always tolerances & with use/age there is wear, so they make room/provisions for adjustment. This is an adjustment & if nothing worn too much or damaged too much there will be enough adjustment. If not, repairs will be needed.
 
The N-Series hydraulic system, when working properly, should sustain a load in the UP position for weeks, months without dropping. 48 hours with 150 lbs, is not good. Just replacing the hydraulic cylinder and piston isn't enough. You say the tractor had been setting out in the woods. Exposure like that usually allows water to get into the system and thus cause all kinds of problems. When water sets in the sump, in cold weather it will freeze. Someone comes along, fires up the tractor, and tries to use the pump when frozen. That usually will cause damage to the pump, cracking and breaking housings and other parts. What was the condition of the oil when you replaced the cylinder and piston? Oil that is a murky brown or whitish color means it is contaminated with water. Hydraulic oil should be a nice, clear-like honey color shade. Did you R&R the valve chambers? The I&T F-04 manual has a good procedure on hydraulic repair and adjustments. There is also a good DVD available from J&D Productions (see LINK) and also from the parts sponsors here on N-Series hydraulic repair. The 9N/2N hydraulic system is a bit different than the later 8N system. The earlier version only had DRAFT CONTROL and the 8N introduced POSITION CONTROL as well. The early systems use a 'wishbone' linkage bracket that must be released by hand BEFORE the top cover i s pulled off. To test for a leaking cylinder, raise up a load and shut off tractor. Look up through inspection holes to cylinder and observe if oil is seeping out of cylinder. Did you use the NAA piston with rubber O-Ring and leather back-up wiper? It is a better design than the original 3-steel ring piston. Did you install a new cylinder or used one? Do some more investigating and report back.

Tim *PloughNman* Daley(MI)
FORD N SERIES HYDRAULIC REPAIR
 
Here is a diagram on hydraulic system function that JMOR put together...


2jQjBgv.jpg
 
Thank y'all so much for the information, I appreciate your time and knowledge.

This sorta worked. It still drops with a tug in the bottom 4 in or so of travel but will hold on the rest.

Any suggestions on where to go from here?
 
"It still drops with a tug in the bottom 4 in or so of travel .."
What does that mean? As in drops if you tug on the top link?
 
(quoted from post at 12:24:03 05/05/18) "It still drops with a tug in the bottom 4 in or so of travel .."
What does that mean? As in drops if you tug on the top link?

If I took the lift arms but not the top link to the Bush hog it will raise and lower. If it is lifted up from the bottom less than 4 in or so and you pull the top link back from the rear of the tractor the implement drops to the ground.

If it's up further then that it holds steady.

When I took up the top link it will only lift until the back of the Bush hog starts to rise which pulls the top link and it falls back down. Once down far enough to release the pull it starts to rise again.
 
After a lifetime of tugging/vibration/etc., the draft plunger shoulder wears into the plate that it rests against. This allows it to rest further to the rear than original. That results in an abnormal input to pump control linkage. This is a command input just as touch control lever is a command input. A new triangular plate is in order, or some 'fix' by modifying a washer as shown here, to make up for that wear.
NXUWv8c.png

5S438CD.png
 
Glad I was reading this, I have a similar problem with mine. When I did the rebuild (pump pisions, hone and NAA lift piston) I took the draft spring apart for a clean and paint. Didn't realize that was wear in the the plate, thought it was a centering counterbore....

As alway guys, thanks for sharing.
 
(quoted from post at 08:13:19 05/06/18) Glad I was reading this, I have a similar problem with mine. When I did the rebuild (pump pisions, hone and NAA lift piston) I took the draft spring apart for a clean and paint. Didn't realize that was wear in the the plate, thought it was a centering counterbore....

As alway guys, thanks for sharing.
....or you can just get a new plate.
ND6VKA9.png
 
Ah, that would mean I spent money. Instead, I can put it off until I get frustrated with it (likely in the middle of a job with it) and then hunt for your pic and a washer to notch and fit.....
 
(quoted from post at 19:59:30 05/06/18) Ah, that would mean I spent money. Instead, I can put it off until I get frustrated with it (likely in the middle of a job with it) and then hunt for your pic and a washer to notch and fit.....
:)
 

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