The Fordson Tractor Pages Forum

Hi,

My hydraulic controls on my power major are slightly different to the normal single lever. I have another lever and rod that I can only imagine is to do with float when doing some draft work like ploughing. I will attach a picture if any one knows how it works or has ever seen it? Or even if it is common and I have missed it on other power majors.

Thanks

Will

That is the preset linkage control, introduced in 1955 for use with the Ransomes TS-73 plough. It's quite rare, but it means you can use implements without a depth wheel at a pre set depth. Enjoy it because most of the ones I've seen were on eBay.
Sandy

Great thank you for getting back to me Sandy. Do you know how it works I see there is a wheel under the lift arm that is seized up I think I’ll need to free that.

Cheers will

here's a leaflet about the preset linkage

https://1drv.ms/u/s!Aqz7UL-t4bk8kHiDbgP1ueZQntSh

https://1drv.ms/u/s!Aqz7UL-t4bk8kHltfH1t2U7gst1C

Excellent stuff Janus! You've got lots of brochures there.
Sandy

JLworld wrote: ↑

Sun May 09, 2021 11:49 am

Do you know how it works I see there is a wheel under the lift arm that is seized up I think I’ll need to free that.

I think you use that wheel to set the depth, but as I haven't seen it in action so I'm not that sure about that.
Sandy

@JLworld

i think you mean the "cam follower" ??

https://1drv.ms/u/s!Aqz7UL-t4bk8kHqk7fI1kMBsibMk

this should move freely !!

I think you should remove it to get it working, as it will be easier, you don't need to remove the cam, just the part in Janus' latest superb picture (the whole thing, not just the cam follower).
Sandy

As everyone has said it is an automatic depth control device, " Pre-set depth control unit". It did not work by sensing draft loads, but by hydraulically adjusting the rear linkage arms when the front or back wheels went over a mound or dropped in a dip to re-set the linkage for the point a second or so later when the plough arrived at the mound or dip.

It worked in conjunction with a special telescoping top link. I have had a number of the units fitted to the tractor over the years, but have never come across an original telescoping top link. Even a posting on this site did not provoke any response! They were reasonably useful on gently changing land, but not as accurate or useful as top link draft sensing systems.

I haven't seen any telescopic top links either, they must be even rarer than the preset linkage control unit that Will has.
Sandy

There is one of the units for the tractor on EBay at the moment, £100, but it is missing the cam plate for the end of the hydraulic lift arm, bit rusty as well.

Thank you everyone for your help with this. I really appreciate all of the responses and great information. I now understand the concept and how to get it going again. The sales leaflet is super.

The telescopic top link is specifically for the long implements that can get stuck or lifted out by an uneven field. If the longest implement you use is as long as a 3 furrow TS-59 or similar you should be fine with a std. top link.
Sandy

It is really only just what it claims to be - a pre-set depth control unit. The lift arm passes through a slot in the hydraulic control lever quadrant, when the linkage is fully raised the arm is at the bottom of the slot, as the linkage drops the cam on the end of the cross shaft causes the arm to rise and contact the bottom of the lift control lever and move it towards the hold position. When the linkage has dropped to the desired point the control lever is exactly in the hold position. That desired point is selected by the set screw position on the unit. In work with a plough the operator can simply push down the hydraulic control lever to the bottom on entry into work, as the plough penetrates and the linkage arms drop the lever rises and contacts the control lever and moves it to the neutral position. Basically the unit saves the operator having to look behind and manually operate the control lever to get the required depth each time the plough enters work.

The telescoping top link allows the rear furrows to remain at a reasonable depth in the soil when the tractor front wheels drop into a hollow or when the tractor rear wheels go over a hump. Unfortunately when the tractor front wheels go over a hump or the rear wheels drop into a hollow the rear furrows are obliged to go deeper. As Sandy says, a normal top link would be OK to use with it for a 2 or even a 3 furrow plough.

Interesting to read about the telescoping top link, we've got one or possibly even 2 of them somewhere here.