3 point lift question

[Cougsfan]

I have a TO35 that I have had for decades. Since I have owned it the 3 point has done something I think of as weird but I have never known if it is the way it should be or is in need of adjustment. The lever lowers the 3 point all the way to full down if it is in the 1/3 "up" position. If I pull the lever back to the full "up position it only goes up about 3/4 of it's full travel. However, if I lower the three point all the way to what intuition would tell you it is all the way down, the three point goes up all the way to full up. I have lived all these years with it because it isn't really a problem, just an oddity. But I have always wondered; Is mine in need of adjustment or is that how it is supposed to work?

 

[redman135]

That is NOT normal for these tractors. It sounds like an internal linkage has gone haywire. I can't help any further as I never did the hydraulics on mine.

 

[Cougsfan]

Anyone have a suggestion of what to adjust?

 

[rScotty]

Anyone have a suggestion of what to adjust?

Yes, it sounds like some dread previous owner tried playig wih the 3pt feedback rod and got it out of adjustmet. Here are some nice old 1970ish Yanmar pictures showing how the 3pt works & what the parts do. But it is a little bit done differently on every tractor & that adjustmet is itslelf real touchy. Half a turn of the adjuster makes a difference.
Anyway, take a look at these illustrations from an old Yanmar manual on their 3pt. The details vary, but every one of Ferguson's 3pts have pretty much the same parts. A genius design. See if these pictures help at all.
Note, the "slow return valve, A--A" s usually internal so you may not see it....but it is in there. And the feedback rod is rarely where you expect it to be. It is obviously adjustable but don't change it until you know what you are doing.
Good Luck,
rScotty

 

[Cougsfan]

Thanks Sotty. I will study these and figure out how things work. I replaced the hydraulic pump once and it works the same before and after so it does appear to be something to do with the linkage somewhere. It sure isn't intuitive and I think these diagrams will help

 

[fatjay]

I have a TO30 for years and I have not received that. If i hit a stump/rock/root with the back blade it'll raise up a bit and wont' go back down. But that's about it. I suspect it's to do with anti-roll-over.

 

[rScotty]

Thanks Sotty. I will study these and figure out how things work. I replaced the hydraulic pump once and it works the same before and after so it does appear to be something to do with the linkage somewhere. It sure isn't intuitive and I think these diagrams will help

The diagrams don't show the suction filter. It would be between the reservoir and the hydraulic pump in that suction line.

 

[Cougsfan]

Yesterday I lifted the control section off the tractor to try and figure it out. I have a Massey Ferguson service manual. It outlines a non-descript set up procedure with set by step method to adjust the various springs and cam, but no explanation of what it is you are doing nor suggestions of what to do when things won't adjust as described (as was the case with my linkage). I also found a U tube video where some gal adjusted the linkage following that same non-descript set up procedure, but again mine simply won't adjust in the manner as described.

rScotty's diagrams did help. The linkage is nothing like shown in his diagrams but the 3 point does work using the same principles. So I adjusted the 2 spring tensions and the cam so all the components moved in a manner that seemed to make the most sense. I put it all back together and tried it. It will now lifts all the way when you pull the lever back, but still also lifts all the way when you push the lever all the way down. To prevent the lifting when the lever is down I simply installed a stop to prevent the lever from being able to be pushed all the way down. So in the end it probably still isn't proper, but the 3 point seems to work in a way similar to how it is supposed to work.
Thanks for the help.

 

[Jerry/MT]

Yesterday I lifted the control section off the tractor to try and figure it out. I have a Massey Ferguson service manual. It outlines a non-descript set up procedure with set by step method to adjust the various springs and cam, but no explanation of what it is you are doing nor suggestions of what to do when things won't adjust as described (as was the case with my linkage). I also found a U tube video where some gal adjusted the linkage following that same non-descript set up procedure, but again mine simply won't adjust in the manner as described.

rScotty's diagrams did help. The linkage is nothing like shown in his diagrams but the 3 point does work using the same principles. So I adjusted the 2 spring tensions and the cam so all the components moved in a manner that seemed to make the most sense. I put it all back together and tried it. It will now lifts all the way when you pull the lever back, but still also lifts all the way when you push the lever all the way down. To prevent the lifting when the lever is down I simply installed a stop to prevent the lever from being able to be pushed all the way down. So in the end it probably still isn't proper, but the 3 point seems to work in a way similar to how it is supposed to work.
Thanks for the help.

The TO-35 has a different 3 point control than the earlier TO series tractors in that it has position control as well as draft control.

Since I assume you have the TO-35 factory service manual and the factory adjustments don't seem to work then I would suspect you have some worn or damaged parts in the control mechanism.

If you don't have the factory service manual but are using the IT type manual, I would suggest you get the factory manual as it has more information on system operation and adjustment.

Good luck!

 

[rScotty]

There's just no substitute for understandiing how it works. Cougsfan, I'm wondering if yours has draft control? If so, the place where the upper center 3pt link attaches to the tractor will be a heavily built pivoting link - often with 3 different positions to attach the 3pt link. Those positions correspond to the different force needed to actuate the automatic draft control.
Draft control has an extra set of adjustments all to itself.

I like that it now works well. Adding a stop to the position lever to keep it from going too far forward makes perfect sense to me.
Congrats,
rScotty