hydraulics

[Mortyouery]

When I went to the farm to bush hog last weekend, I had no lift movement at all. I hooked up the bush hog but it wouldn't budge. When I lengthened the top link, as it got firm the hydraulics came alive and up they came.

The week before, I had no response when I hooked up my cultivator. After trying this, that, and the other thing, I pulled forward and as the teeth dug in the hydraulics came alive. I cultivated 4 acres and the lift worked flawlessly.

There appears to be a relationship between pressure on the top link and proper function.

Could it be that the pump is getting a "signal" as though the "draft control" function is activated and is bypassing the touch control lever, until force is exerted on the top link which "wakes up" the touch control function? What failure within the pump would cause this?

I have not peered inside yet for fear I'll disable the tractor when I'm in the middle of planting milo and millet. I have all of your excellent suggestions from my post a few weeks ago. Just wondering if any of you pump masters can point to a suspect based on the above description....

 

[souNdguy]

Is the tractor actually in position control mode instead of draft control?

Once hyds 'start' working.. do they then work normal with the touch control lever?

Fear not, you can remove the top cover completely, turn off the pto and throw a board over the open sump to set on, and drive the tractor out of the field.

depending on the answers to the questions I posed.. could be a few things.. anything from bent/worn/broken linkage or cam pin to ??

post back.

soundguy

 

[souNdguy]

oops.. i just assumed 8n here.. but is this an 8n or a 9n/2n.. if 9n/2n, no cam pin.. no position control..etc..

soundguy

 

[Bill McCormick]

If you have an I&T manual on this tractor, It covers the lift adjustments very well and also the principles of how the whole system works. It's a little technical but if you follow the instuctions closely you can check all the settings on the lift while it is on the bench. Since yours developed a sudden problem, it will probably be something obvious once you get the lift cover off. Mine had a worn through follower pin that follows the cam. It's been ten years since I fixed it and it had worked perfect ever since. When you pull the cover off, the hydraulic pump and valves will remain in the bottom of the tractor case. Since your lift will work sometimes, it's probably a mechanical problem in the top half.

Below is a link that covers common issues on 8n hydraulics.
8N Hydraulics

 

[Mortyouery]

It is a late 47 8n. Position control lever is vertical (off). In horizontal position there is zero touch control response.

Once it activates, it works reasonably well with a plow, cultivator, disk, moderate to poorly with a bush hog, and poorly with the 2 row planter (which has a floating draw bar). Could it be when the pump is elongated as when the plow or cultivator is in the ground it works well but not when the pump stroke is shorter? The lift arm pins are highest off the ground on the planter and bush hog when I ask it to lift these implements and they are the most problematic.

 

[Dunk]

(quoted from post at 11:33:48 07/15/09) It is a late 47 8n. Position control lever is vertical (off). In horizontal position there is zero touch control response.

Once it activates, it works reasonably well with a plow, cultivator, disk, moderate to poorly with a bush hog, and poorly with the 2 row planter (which has a floating draw bar). Could it be when the pump is elongated as when the plow or cultivator is in the ground it works well but not when the pump stroke is shorter? The lift arm pins are highest off the ground on the planter and bush hog when I ask it to lift these implements and they are the most problematic.

Look over this topic.
http://ytforums.ytmag.com/viewtopic.php?t=498343

 

[souNdguy]

Up/vertical IS position control.. not 'off' like you are specifying.

I'm guessing you may have one or more problems with worn linkage, plus perhaps dirty oil that may be making the control/exhaust valve stick.

soundguy

 

[Mortyouery]

Holy Moly Soundguy! That makes sense then. The lift is responding to the pressure on the tractor end of the top link because it is in draft control. Unfortunately, when not in draft control (horizontal) I have zippo at the touch control which is why I have thought that was draft position. I read in other posts that even in the draft control position, the touch control should raise the implement, just not as high. Is that accurate?

Others ahave mentioned adjusting the touch control mount to see if that helps. I see 4 bolts that attach the touch control bracket but do not see how they would allow adjustment. Does anyone have pictures or a description of that?

Clearly when I get planted I need to bite the bullet and check/pull the pump. Ugh.

 

[Dunk]

(quoted from post at 11:15:41 07/16/09) Holy Moly Soundguy! That makes sense then. The lift is responding to the pressure on the tractor end of the top link because it is in draft control. Unfortunately, when not in draft control (horizontal) I have zippo at the touch control which is why I have thought that was draft position. I read in other posts that even in the draft control position, the touch control should raise the implement, just not as high. Is that accurate?

Others ahave mentioned adjusting the touch control mount to see if that helps. I see 4 bolts that attach the touch control bracket but do not see how they would allow adjustment. Does anyone have pictures or a description of that?

Clearly when I get planted I need to bite the bullet and check/pull the pump. Ugh.

I have a pic of a 9N that you can see the slotted holes, but you have to understand that in the pic the quadrant is bolted on 90* from what it should be, in this pic it appears to go up and down, but if it was on there right, it would go fore and aft.

 

[Mortyouery]

Dunk - great picture, thanks. See if I understand what you are saying about 90*. Do you mean the quadrant in the picture is not installed properly and that if it were, the bolt in the picture would pass thru the one hole which is not visible, and that the slots would then allow adjustment fore and aft versus up and down (as in the picture)?

 

[Dunk]

(quoted from post at 11:29:43 07/16/09) Dunk - great picture, thanks. See if I understand what you are saying about 90*. Do you mean the quadrant in the picture is not installed properly and that if it were, the bolt in the picture would pass thru the one hole which is not visible, and that the slots would then allow adjustment fore and aft versus up and down (as in the picture)?

Yes!!

 

[Mortyouery]

Great! Now, what am I affecting when I adjust by sliding the quadrant fore versus aft? Is it ok to be running the PTO to observe the affect on the touch control/lift arms as I adjust the position?

 

[Dunk]

(quoted from post at 14:49:39 07/16/09) Great! Now, what am I affecting when I adjust by sliding the quadrant fore versus aft? Is it ok to be running the PTO to observe the affect on the touch control/lift arms as I adjust the position?

It would affect the amount the linkage pushes the control lever at the bottom at the pump valve control.

I don't see any reason it would hurt it to be running.

If I remember correctly, I had to loosen the 4 bolts, and then take a drift and tap mine fore and aft.