Farmall M hydraulic problem

[Jay Liedman]

I tried using the hydraulics on my M to lift up my corn planter, and have run into a problem. It lifts just fine, but even if you depress the lever all the way it will not let the machine go down. I do not know much about hydraulic systems. I assume it is a malfunctioning valve somewhere. What is the likely cause, and how big a job am I looking at to get it fixed?

 

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I tried using the hydraulics on my M to lift up my corn planter, and have run into a problem. It lifts just fine, but even if you depress the lever all the way it will not let the machine go down. I do not know much about hydraulic systems. I assume it is a malfunctioning valve somewhere. What is the likely cause, and how big a job am I looking at to get it fixed?

First question:
Is it an add-on live hydraulic pump system or the original Lift-all system?

Is it still the factory setup or has a lot of aftermarket things gotten added (valving and hoses wise)?

 

[Jay Liedman]

First question:
Is it an add-on live hydraulic pump system or the original Lift-all system?

Is it still the factory setup or has a lot of aftermarket things gotten added (valving and hoses wise)?

Original Lift-all, as far as I can tell. It is operated by the pull lever on the right side of the tractor. The rest knob on the pull lever is what keeps the unit raised.

 

[rustred]

I tried using the hydraulics on my M to lift up my corn planter, and have run into a problem. It lifts just fine, but even if you depress the lever all the way it will not let the machine go down. I do not know much about hydraulic systems. I assume it is a malfunctioning valve somewhere. What is the likely cause, and how big a job am I looking at to get it fixed?

Are both hoses plugged in good ?

 

[the tractior vet]

I tried using the hydraulics on my M to lift up my corn planter, and have run into a problem. It lifts just fine, but even if you depress the lever all the way it will not let the machine go down. I do not know much about hydraulic systems. I assume it is a malfunctioning valve somewhere. What is the likely cause, and how big a job am I looking at to get it fixed?

If it raises fine BUT will not drop change your couplers , BOTH of them . had that issue with my 706 way back drove me bonkers only did it on the planter . I was always in a rush when farming as spending all day running around fixing other peoples problems and farming well into the WEEEE hours of the morning it drove me up a wall while lifting making the turn and slamming the lever down to drop the planter and it would drop half way and stop making me do a 180 and try again to get the planter to drop then only having to stop dead and ease the planter down . Then go eating time the one thing i did not have a lot of . Bought two new couplers male and female and solved my issue , now i could make my turns at 5 MPH slap the lever and go never slowing down

 

[rustred]

Yes I have seen bad couplers do that .

 

[the tractior vet]

Yes I have seen bad couplers do that .

should have asked if he is running ONE hose or two . i ran signal action on my planter one hose . When you tried to make it drop like a rock she would lock up , but if you STOPPED and eased it down REAL slow it would go down . On M's there is nothing real slow going down you shove the control rod all the way forward and everything drops like a rock So i would say the male coupler is slamming shut . due to a weak spring in the female coupler.

 

[wh]

If using belly pump the few internal parts that act as a valve may be sticking. Been several years since I was inside of one.

 

[used red MN]

If using belly pump the few internal parts that act as a valve may be sticking. Been several years since I was inside of one.

Balls against seats are what the valves are. Moving the lever forward unseats a ball to let fluid flow back out to allow a connected cylinder to lower. At 12 minutes in the attached video is where the explanation of the valve system starts and continues in segments until almost the end of the video. Another thing I’ll mention is It depending on how much weight you lift this changes how hard the lever has to be pushed to unseat the balls. A later modification somehow changed the size of the ball that is initially pushed to a smaller diameter which is easier to unseat against pressure and then a second larger opening unseats to allow the same flow the original sized valves flowed.
I agree with others to first check that the hydraulic couplers if used are plugged in correctly an are allowing the fluid to flow back as they should.
Pete from few acres rebuilds lift-all

 

[Jay Liedman]

should have asked if he is running ONE hose or two . i ran signal action on my planter one hose . When you tried to make it drop like a rock she would lock up , but if you STOPPED and eased it down REAL slow it would go down . On M's there is nothing real slow going down you shove the control rod all the way forward and everything drops like a rock So i would say the male coupler is slamming shut . due to a weak spring in the female coupler.

It is a ONE hose setup. I did finally get it to work. I unhooked the control rod, then pushed the lever further to see if that would make a difference.. When the lever was pointed all the way to the ground, it allowed the planter to drop. I ended up taking the lever off, then reattaching it about 180 degrees from the original position. Hooked up the control rod again, and for whatever reason it now works properly in that position.

 

[D Slater]

It is a ONE hose setup. I did finally get it to work. I unhooked the control rod, then pushed the lever further to see if that would make a difference.. When the lever was pointed all the way to the ground, it allowed the planter to drop. I ended up taking the lever off, then reattaching it about 180 degrees from the original position. Hooked up the control rod again, and for whatever reason it now works properly in that position.

If one hose hooked to rear port on left the lever needs to go just a little more forward than other outlets on unit to unseat oil return back.

 

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If one hose hooked to rear port on left the lever needs to go just a little more forward than other outlets on unit to unseat oil return back.

Yes, the back left port has a delayed drop/raise function. Mostly used for raising/lowering cultivators.
Which if you have your hose hooked to that port D Slater explained your lever travel issue.