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Adam - NC

Farmall 240 Hydraulics

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We are struggling with hydraulic issues on our Farmall 240.  We had a bad pump, and bought a junk yard pump because new ones are not available.  Our pump is slightly larger than the new pumps available for the 140 and similar tractors.  The used pump primed quickly and seems to work well.

Our tractor had 2 'hydra-touch' valves for cultivators, and one 'tel-a-depth' valve for the rear lift.  We removed the hydra-touch valves when we painted it and made shorter rods for the hydraulic block assembly simply to reduce the number of places we could leak oil.  We changed all the o-rings between the blocks and in the relief valve. Currently, we have a pressure gauge on the down side of the rear lift hydraulics.  When the lift lever is moved to the rear and the cylinder bottoms out, we are seeing about 1200 psi at high idle.  When dead headed like this the pump makes an awful racket and bogs the engine severely.

 

Question 1 - should the relief valve be opening up to take pressure off the pump, or is this the way the tel-a-depth valve works?  We do not have the follow up linkage to recenter the valve once the lift moves to match the lift lever.  If we manually move the lift lever to the center the strain on the hydraulic pump is relieved. 

Question 2 - what pressure should a good pump on this tractor make?  I was expecting more like 2,000psi, but I don't know what it should do.

Question 3 - If we put one or both of the cultivator valves back on, would that allow a path to the relief valve when the tel-a-depth valve was dead headed?

Question 4 - one option we are considering is replacing the tel-a-depth valve with a hydra-touch valve and running hoses from the valve to the rear lift cylinder.  The rear lift would be controlled by one of the hydra-touch handles on the right side of the dash rather than the lever on the right side of the seat.  These valves return to center when you release the lever, so you would hold the lever until you get the lift where you want it and then let is return to neutral.  Are there any problems with this thought that we are missing?

A few pictures to illustrate our set up - 

Tel-a-depth valve currently controlling our rear lift.  Not that the hydra-touch valve has been removed on both sides.

IMG_7794.thumb.JPG.53d84873c01291b09c42aa68b7abd17c.JPG

 

Missing follow-up or feedback linkage - I assume that the feedback linkage that connects the lift cylinder to this piece under the seat would move the lift lever back to a neutral position when the lift  moves to the selected position?

IMG_7795.thumb.JPG.d6843f9eda54714f1e3e7179d79d8176.JPGIMG_7796.thumb.JPG.1674b0eec4d92f6b1d84ced463a7c1c6.JPG

This is where we put a gauge temporarily to see what the pump was actually doing.   We had 1200 psi when the lift was all the way down.

IMG_7797.thumb.JPG.cc5587684fdee7665acd49bd984a48f0.JPG

 

We have a thread for this project in the projects forum, if you have time to kill head over there and see how far this tractor has come since 2017.  My son (15) has done a lot of the work and almost all of the painting.  I complain about the money we've spent, but he has learned a lot, and has invested a good chunk of his money as well.  I'm proud of how hard he has worked and his attention to detail on this tractor.

IMG_7798.JPG

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I will get a bit more in depth here. Normal operating pressure is 1200-1300 PSI. The system is a open centered system that is not on pressure until a pilot control circuit built into the valve(s) is closed due to movement of the valve actuator. The flow divider then delivers pressure from the pilot circuit(control circuit). So normally there is little pressure against the pump unless being used to do work. In the pics attached there is a good view of the tele depth valve that when you move the lever one side moves the valve and when the other side catches up the valve will center taking the system off pressure. If you are moving the lever by the seat most the linkage to the valve is good but the feed back is not happening because of the missing parts that are some what shown in the pics from a utility 460 which operates the same but is not necessarily exactly the same( something may still be stuck as one side of the valve is staying in place when you move the quadrant lever. On my larger tractors I put a regular valve on that does not have a quadrant and will self center when you release the handle. Others will chime in and I feel you should try salvage yards as the linkage has enough(variables) to be a real challenge. If you decide to build get the hitch to a center of travel place by dropping it to the floor and then raising to the top of travel measure in between and block the hitch in the center. With the tractor not under pressure get the quadrant to the center and measure what you need for lengths. As you can see in the pics there is a complex arraignment to the linkage. Researching the case  ih parts site may give you other tractors that may use the same parts. Like I mentioned in the other post I have not been near the 240 I had in probably 5 years so some things are memories but I used that tractor from the 70s into the 90s.

hitch linkage pivot.jpg

tele depth.jpg

linkage under seat.jpg

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Thanks for your response - 

I don't see how my valve can work like your second picture would - in the original manuals there was a separate linkage all the way to the valve, but I think an update happened somewhere along the way and the feedback system was changed.  There is only one lever on the outside of my tel-a-depth valve.

Do you thing using a hydra-touch valve for the rear lift is a workable solution, rather than finding / building the complex feedback circuit?

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Anyone have piece numbers 19 & 21 for sale, or parts on a tractor that you can give me measurements from?

image.png.cc6a32f896cf1ea56d24c96f27815ed5.png

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I believe so. A regular self centering valve will bolt right in the place of the tele depth valve or the cheapest thing would be to use one of the two valves that I see are already in your picture of the tractor. Ours only had one of them so yours is better equipped than ours  was. If there is a way to get the lever by the side of the seat to self center by itself changing the valve would be the cleanest way, I am not sure if taking the brake loose is all that it would take and changing the valve.  If using a front mounted piece of equipment you would have t for both sides. I am not sure but maybe a handle set up from a 560 with three self centering valves would get the needed lever to move the valve but not sure if it would work . 

comment--changing it to the way I describe gets it to work but the function of being able to set it to a certain spot and repeats is lost which was a nice feature.

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The 240 uses a completely different, and much simpler, system than the 340/460/560. The missing linkage is your issue. I had very in-depth experience with the system when I owned a 240 Utility several years ago.

Be aware that there are "left hand" and "right hand" valves when you are shopping for a self-centering valve. Referring to the location of the lever.

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46 minutes ago, Matt Kirsch said:

The 240 uses a completely different, and much simpler, system than the 340/460/560. The missing linkage is your issue. I had very in-depth experience with the system when I owned a 240 Utility several years ago.

Be aware that there are "left hand" and "right hand" valves when you are shopping for a self-centering valve. Referring to the location of the lever.

I have one of each - Mine had cultivator valves on each side as well as the tel-a-depth for the rear.  We took the cultivator valves off and put them in the toolbox to reduce leaks.  If someone chimes in with measurements on the missing linkage we can try to reproduce that.  If not, the different functionality of the hydra-touch valves will not bother us.

Thanks for the replies!

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