784 hydronic lift issues

Lwfvt802 · Apr 11, 2022

International 784

Foolishly used draw bar to haul trailer (thinking I would lift control arms to dump) trailer gets too heavy tips back, forcing draw bar and control arms up.

Result: control arms not working, hydraulic steering seems to work at times and not others pto still works. No leaking fluid.

Have a shop book which highlights in the trouble shooting section: the main relief valve, the cushion relief valve or internal linkage as problem

Janicholson · Apr 11, 2022

The Draft control linkage in the far back of the housing is a likely suspect. They do not like to be beyond the upper limit. Access might be through the top link attachment
bracket. It is an issue that is pretty easy to fix on a big frame IH, I am uncertain on that more modern tractor. Jim

caterpillar guy · Apr 12, 2022

Always start with the easy and cheap stuff first. If the filter has not been changed do that. Check oil level and Look at the draft lever to see if it has been changed. Some of them will affect the lift lower levers actions. Our 574 one time would not go lower or would not lift ,can't remember but moving the draft lever was the problem. So I would start there if no joy then may have to look deeper. Will they drop on their own or go up left unloaded. The if they lift and lower empty try a load on them again stand on them or heavier. If still no then you will have to look inside.

MARK ROBKE · Apr 12, 2022

I am wondering if the internal lift cylinder came apart from the lift arms raising too high, and then blew
out the piston. I don't know if that is possible, but it's my thought. Mark.

JimB2 · Apr 13, 2022

Hi, is the 3pt under high pressure all the time now? Both draft and 3pt Lift levers fully forward? Which service manual do you have IH or I&T?
There is a mechanical cam follower mechanism that rides on the 3pt rock shaft that feeds back the position on the 3pt lift to close a valve to stop lifting when the 3pt lift reaches the position equal to the
position of the 3pt lift lever and the draft control lever setting. I suspect as the other Jim suggested is the cam follower has gone beyond its limit. The valve and cam follower can be accessed through an
inspection plate on top of the 3pt housing under the seat and deck plate. There should be a section in your service manual about adjusting the maximum height of the 3pt lift that shows the valve spool and
adjustment of cam follower feedback mechanism. If you are lucky and nothing was damaged, it maybe possible with the tractor shut off and a screw diver, you can pry on the valve spool to release the pressure on
the 3pt lift cylinder and the 3pt arms will go down.

Mich John · May 2, 2022

(quoted from post at 06:59:09 04/13/22) Hi, is the 3pt under high pressure all the time now? Both draft and 3pt Lift levers fully forward? Which service manual do you have IH or I&T?
There is a mechanical cam follower mechanism that rides on the 3pt rock shaft that feeds back the position on the 3pt lift to close a valve to stop lifting when the 3pt lift reaches the position equal to the
position of the 3pt lift lever and the draft control lever setting. I suspect as the other Jim suggested is the cam follower has gone beyond its limit. The valve and cam follower can be accessed through an
inspection plate on top of the 3pt housing under the seat and deck plate. There should be a section in your service manual about adjusting the maximum height of the 3pt lift that shows the valve spool and
adjustment of cam follower feedback mechanism. If you are lucky and nothing was damaged, it maybe possible with the tractor shut off and a screw diver, you can pry on the valve spool to release the pressure on
the 3pt lift cylinder and the 3pt arms will go down.

Did you resolve this issue yet - I have the same problem so hope to see what you did to correct.
If issue persists, this same "hung-up in transport position for 3 pt arms" is ALSO discussed in the Red Power Forum under 784 hydraulic hitch stuck in General IH forum - Snoshoe and -Mech have some good input on this issue!

Lwfvt802 · May 2, 2022

(quoted from post at 06:43:44 05/02/22)

(quoted from post at 06:59:09 04/13/22) Hi, is the 3pt under high pressure all the time now? Both draft and 3pt Lift levers fully forward? Which service manual do you have IH or I&T?
There is a mechanical cam follower mechanism that rides on the 3pt rock shaft that feeds back the position on the 3pt lift to close a valve to stop lifting when the 3pt lift reaches the position equal to the
position of the 3pt lift lever and the draft control lever setting. I suspect as the other Jim suggested is the cam follower has gone beyond its limit. The valve and cam follower can be accessed through an
inspection plate on top of the 3pt housing under the seat and deck plate. There should be a section in your service manual about adjusting the maximum height of the 3pt lift that shows the valve spool and
adjustment of cam follower feedback mechanism. If you are lucky and nothing was damaged, it maybe possible with the tractor shut off and a screw diver, you can pry on the valve spool to release the pressure on
the 3pt lift cylinder and the 3pt arms will go down.

Click to expand...

Did you resolve this issue yet - I have the same problem so hope to see what you did to correct.
If issue persists, this same "hung-up in transport position for 3 pt arms" is ALSO discussed in the Red Power Forum under 784 hydraulic hitch stuck in General IH forum - Snoshoe and -Mech have some good input on this issue!

Not solved yet. Lift arms are in lowered position and will not raise. I can lift by hand. Draft control is a suspect but first planning to hook hydrolic flow meter (min 5000psi) to Mcv to check relief valve.

Lwfvt802 · Sep 6, 2022

(quoted from post at 07:33:57 04/11/22) International 784

Foolishly used draw bar to haul trailer (thinking I would lift control arms to dump) trailer gets too heavy tips back, forcing draw bar and control arms up.

Result: control arms not working, hydraulic steering seems to work at times and not others pto still works. No leaking fluid.

Have a shop book which highlights in the trouble shooting section: the main relief valve, the cushion relief valve or internal linkage as problem

>>>>UPDATE<<<<

Thank you for the helpfull suggestions. the lift arm issue has been resolved: broken spring in mcv; new hydrolic pump (intake screen was blocked with field debris as well).

...NOW PTO not working... no oil pressure leaving the mcv valve to the pto, checked pto clutch valve seems okay, checked pto regulating valve (replaced poppet in valve) now seems okay.

...has been suggested it could be to do with dry clutch: splines on tube shaft worn off. means breaking tractor in half.

any suggestions? NOte: the pto was "kind of" working before we did initial repair to fix lift arm problem. now no pto at all. steering seems fine.

Mich John · Sep 9, 2022

(quoted from post at 05:04:50 04/12/22) Always start with the easy and cheap stuff first. If the filter has not been changed do that. Check oil level and Look at the draft lever to see if it has been changed. Some of them will affect the lift lower levers actions. Our 574 one time would not go lower or would not lift ,can't remember but moving the draft lever was the problem. So I would start there if no joy then may have to look deeper. Will they drop on their own or go up left unloaded. The if they lift and lower empty try a load on them again stand on them or heavier. If still no then you will have to look inside.

I wish someone WOULD SOLVE THIS ISSUE W/O HAVING TO REMOVE THE FUEL TANK/FENDERS AND THEN THE ROCKSHAFT HOUSING COVER TO EXPOSE ALL THE INTERNAL HYDRAULIC SYSTEM. I can lower the 3 pt arms ONLY if the draft control and position control lever are forward by taking off the inspection cover and, using a screw driver, push forward on the main valve arm assembly (see IH parts catalog, hydraulics group 10 pg 17). As soon as the engine starts, however, the 3 pt. arm goes up to the transport position again. The hydraulic system schematic doesn't show where the various system components are located BUT am sure getting at involved what I stated above (i.e., a lot of work). I will try to do as JimB2 suggests with regard to adj. max. height of 3 point lift. I know there is NO access "through the top link attachment similar to big frame IH tractors".
Hoping to hear a NOT TOO INVOLVED SOLUTION!

Lwfvt802 · Nov 14, 2022

(quoted from post at 07:33:57 04/11/22) International 784

Foolishly used draw bar to haul trailer (thinking I would lift control arms to dump) trailer gets too heavy tips back, forcing draw bar and control arms up.

Result: control arms not working, hydraulic steering seems to work at times and not others pto still works. No leaking fluid.

Have a shop book which highlights in the trouble shooting section: the main relief valve, the cushion relief valve or internal linkage as problem

Solved: had to replace entire mcv valve likely had an internal fracture, impossible to see but lack of oil pressure indicated that as possible problem. Used part $650 problem solved. After close to $3000 worth of labor and parts lesson learned: no substitute for experience (as it pertains to specific equipment) and sometimes it pays to replace.

784 hydronic lift issues

Lwfvt802

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Janicholson

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caterpillar guy

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MARK ROBKE

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Mich John

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Mich John

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