TO35 Draft Control Linkage

[DCA]

I just finished a complete overhaul of the upper hydraulic system. The position control works great and will easily raise a heavy implement to the transport position even at idle. However, the draft control barely lifts it off of the ground. I am wondering if I got the draft control lever on the wrong side of the roller on the draft control link.

I am also getting some jerkiness as the implement is raised with the position control.

Hopefully there is an expert out there that can point me in the right direction.

 

[Anonymous-0]

I hate to be the bearer of bad news, but when you overhauled the top end of the system you needed to adjust the control levers to the correct position and tension per the overhaul manual(too complicated for this answer). I suspect you did not do that or you would get a little more draft control action. I don't think the draft control lever is behind the control valve roller or you would not get any response I suspect. I am sure John of UK will weigh in here, but in case he does not, email me and I will send you the instructions.

Phil(WA)

 

[DCA]

Thank you for the response, Phil.

This turned into a long and costly job, when I started out thinking that I just needed to make those adjustments you are referring to. The I&T manual says they can be done thru the inspection cover on the right side, but I soon concluded that was impossible. (I also have the original factory shop manual). And both levers were limp against the guide, so I proceeded to remove the cover.

As a complete novice (then) I spent several hours figuring out how the controls worked. Then I realized that there was about a .060 gap between the cam on the ram arm and the roller on the position control link assembly when the lift position lever was set at "Fast" response. I found that roller has .025-.030 wear, there was a groove about .035 deep on the ram arm cam and the roller on the position control shaft was also worn .025 or more. And the lift shaft bushings were worn .012 or more on both the internal and external diameters. So there was no way to make that first adjustment to set the lift position lever position with the nut on the spring guide.

These items were all replaced and the adjustments made on the bench. and the nut on the valve control lever was adjusted when the cover was re-installed on the tractor.

I do know that both the position control and draft control levers are to the front of the pump valve control lever, so that is not the issue. For some reason the draft control lever is not moving the valve control lever far enough. That is why I wondered if I have the draft control lever on the wrong side of the roller on the draft control link assembly in the attached picture.

If that is the correct position, I think something might have happened when the cover was turned upside right to put it on the tractor and that lever might have slipped from above the roller to below it. Does that make sense?

To answer a couple of questions for other viewers that I have seen on this forum:

My TO35 is an older deluxe model with the old style hydraulic pump. It had a 2 1/2 inch lift cylinder (no longer available), which I replaced with the 3 inch cylinder assembly used on the later models. (The cylinder, piston and rings were all scored and the lift arms would sink like a rock when the pump was stopped). The one change is that the mounting holes will need to drilled out from 7/16 to 9/16.

With this new cylinder, piston and rings, the sink rate is about 1/2 inch per minute with a 60" roll over box. I think it weighs about 700 lbs. And it will lift this load at a low idle speed without breaking a sweat.

David in Garlic Country

 

[Anonymous-0]

David, if you email me I can send you a color photo of the area of your concern and you can check it against your assy.
I overhauled mine in much the same way you described but it was so long ago I don't remember the linkage that well any more, but his photo should help.

Phil(WA)

 

[John (UK)]

The hydraulic system on your tractor isn't supposed to lift on the Draft Control, you use the Position Control Lever to lift the three point linkage. If you have a heavy implement mounted, as you lift it will pull on the top link and this will move the Control Valve which will limit how much it lifts. If you have a relatively light implement and it won't lift then you should check that there is no free play (in and out) of the top link connection as this will also alter the setting of the Control Valve. If you would like the correct instructions for operating this hydraulic system just email me and tell me what you need again and I will send it.You also need to set how much the hydraulics lift before they shut off, this is an external setting and is easy to do but it has to be set correctly, ask for this as well if you need it. If you need the info on setting the Draft Spring free play at the back of the seat, again just ask...John
email..fergusontractors @ tiscali.co.uk

 

[John(UK)]

You do have the levers set correctly, it isn't a .060" gap to which you need set it. there has to be a pull of 3lbs to close the gap, that is the spec for this setting. The reason for the draft lever not moving as far is, if there is anything either pushing or pulling at the Draft Control Spring on the top link it will alter all this linkage. From how you describe it, your system is OK and it may just require "tweaking" to get it right.I can send you the details of how to set the control valve linkage(simplified) if you need it, just email me..John

 

[DCA]

John,

Thanks for the help. I sent an email to you with more of an explanation, so this post is for the benefit of others that might read this thread.

I was chasing a problem that was not a problem. The implement I had mounted was just too heavy to use with draft control (approx. 700 lbs). (Using Position Control it is rises with no problem). With a lighter implement, draft control and response control work as expected.