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Discussion Starter #1
I just started a job at a turf farm and inherited a broken 2040. The data plate is either missing or covered up by the arms for the homemade ballast box, but I believe it's a 79 s/n 324720.

The problem(s) it's having is that the 3-point hitch won't lower (it raised automatically when I first started the tractor last week), and the hydraulic steering isn't giving any assist. Prior to me starting here it had the hydraulic pump replaced, I believe for the same hydraulic problem(s) I'm dealing with.

The pump is working, because a hose blew the other day and shot fluid 20 feet to the ceiling.

The auxiliary hydraulics for the implement also load the engine when the control lever is deadheaded, but there's absolutely nothing going on when I raise or lower the draft control lever.

I already took off the transmission top cover to check for anything binding, broken, or loose, but without a diagram I could have missed something. I noticed that the 3-point hitch arm shaft has a piston that appears to go into a tapered cylinder with what looks like a nozzle at the bottom, which I assume blows hydraulic oil out to push the piston out and raise the hitch arms. The arms do not lower by manual pressure.

I also poked around in the rearend center section to see how the draft control works, and believe I have the clevis properly aligned on the little "hammerhead" lever.

As far as the steering, I'm starting to think the hand pump may be worn out because it was used without power steering for quite some time. Right now I'm waiting for a tee so I can check pressure at the pressure line going to the steering motor, and maybe I'll try to find a service manual for this thing. Any help will be appreciated, hopefully I separated my thoughts and worded them in a way that can be understood. Thanks.
 

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Discussion Starter #4
Thanks, I’ll take a look at that valve adjustment tomorrow. I’m assuming all the way in is closed?
 

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Welcome to GTT
Ditto on possibility of R-O-D screw being totally closed. I witnessed several had been closed getting on/off tractor when I was employed at a JD dealership. Since you don't know serial number can you post a photo of the hyd pump in frt of radiator. With aid of photo of hyd pump it can determined if tractor hyd's are open or closed center. When you reinstalled rockshaft housing did you get cam follower to the rear of rockshaft control linkage roller?
 

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Discussion Starter #6 (Edited)
Welcome to GTT
Ditto on possibility of R-O-D screw being totally closed. I witnessed several had been closed getting on/off tractor when I was employed at a JD dealership. Since you don't know serial number can you post a photo of the hyd pump in frt of radiator. With aid of photo of hyd pump it can determined if tractor hyd's are open or closed center. When you reinstalled rockshaft housing did you get cam follower to the rear of rockshaft control linkage roller?
If the cam follower is the 1/4" thick metal arm with T-shaped ears on it a little to the right of center, yes, I lowered the cover at an angle and used lineup pins to hold the rear in place while I ensured the linkage was underneath the ears on the follower. I'll post a pic of the pump in a few.

(Yes, I know the hose in the 2nd pic is loose :lol:)

48F5150E-799A-4491-97F5-4102FF54028A.jpeg

F4DF919F-563C-40CB-A4E2-2076691A2700.jpeg
 

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Discussion Starter #8
I know it has hydraulics from the shower I took the other day, so now (as soon as I stop being the rope in a 5-way tug of war) I'll figure out how to check pressures in the steering. With everything being done inside the case it's not like your generic hydraulic orbit motor steering. Time to find a service manual, I think.
 

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Discussion Starter #10
Parts & tech manuals are on the way. I decided to pull the rockshaft housing off and take some pics in the hope that someone can point something out to me.

Viewed from the left rear. This is the lever (cam follower?) that I had the rockshaft control roller & ears around.

AC476AAF-5F74-45C0-89A1-41A6E1C053DA.jpeg


Viewed from the left front.

DA7A25B4-4B7E-42A2-AFD3-10FF61E82478.jpeg


The control lever roller and ears.

E4034337-FDAC-4B2D-BCC9-76D0230F6C15.jpeg


Rockshaft control linkage.

60C1667C-F0FF-44F2-996E-52537690CD74.jpeg


The lever at 4 o’clock to the rockshaft, which seems to move the rockshaft lever ears up and down on the cam follower.

54C882B7-BA4A-4BC4-889F-8646D79B2098.jpeg
 

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Discussion Starter #11
Well I pulled off the rockshaft housing after lunch today and found the piston won’t retract. Even with the rockshaft plunger removed, ROD adjuster & ball out, and linkages disconnected the piston is stuck about an inch from full up stroke. I couldn’t get the cylinder out, but I found the hidden bolt (hidden when the cover is upside down, anyway) and will pull the cylinder out tomorrow. I’m interested to see what’s in there!
 

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Discussion Starter #13
Did you have the roller positioned in "front" of the cam follower?
Yes, it was a bit of a chore getting my hand in there to guide it on as I lowered the rockshaft housing but I managed.

I have the cylinder out, the piston slid out with careful application of shop air to the ROD adjuster bore, and there’s a LOT of fines in the oil that came out of the cylinder. Now to find out what was keeping the oil from flowing out of the cylinder when the rockshaft lever was pushed forward.
 

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Now to find out what was keeping the oil from flowing out of the cylinder when the rockshaft lever was pushed forward.
Considering that the piston moves freely within the cylinder bore, the Rate of Drop ball(#4) must be off it's seat, to direct oil will flow to the Return Valve(#3). When the Return Valve(#3) is opened(moved off it's seat) when rockshaft lever to pushed forward, oil will flow to Sump, allowing the rockshaft piston to move farward(lowering the lift arms).


What I'm saying is, if the piston it not sticking in the cylinder bore, the problem must be lack of oil flow to the sump, by means of, 1)-ROD ball is fully seated. 2)-Return valve is not opening.

Return Valve operation(movement) is controlled by internal linkage, and must be adjusted properly to function as designed.
 

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Discussion Starter #15 (Edited)
Considering that the piston moves freely within the cylinder bore, the Rate of Drop ball(#4) must be off it's seat, to direct oil will flow to the Return Valve(#3). When the Return Valve(#3) is opened(moved off it's seat) when rockshaft lever to pushed forward, oil will flow to Sump, allowing the rockshaft piston to move farward(lowering the lift arms).


What I'm saying is, if the piston it not sticking in the cylinder bore, the problem must be lack of oil flow to the sump, by means of, 1)-ROD ball is fully seated. 2)-Return valve is not opening.

Return Valve operation(movement) is controlled by internal linkage, and must be adjusted properly to function as designed.
The piston was stuck to the point that neither pulling down on the rockshaft arms nor pushing directly on the piston with a hammer handle would move it. I ran solvent into the ROD & check valve passages, a LOT of fines and old, dirty oil came out, and then air blown into the ROD port (with check valve reinstalled) slowly slid the piston out. Now it moves in and out freely. I'm going to reseal the cylinder and reassemble everything, then lift it with air & make sure it lowers by hand before reinstalling the rockshaft cover. Of course, there's no seal kit in the parts room so I have to wait until Tuesday or Wednesday for it.

Both valves move, not knowing what's been done to this thing in the past I'm going to assume something was misadjusted. Would you happen to know whether the high or low side of the eccentric on the rockshaft control lever goes up or down?
 

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Since metal fines were present in RS cylinder bore I think one should check condition of axle brake pads. Sounds as if metal fines were locking RS piston in it's bore.
 

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Discussion Starter #17
Since metal fines were present in RS cylinder bore I think one should check condition of axle brake pads. Sounds as if metal fines were locking RS piston in it's bore.
I doubt I'll be able to do anything to the brakes until winter, when operations cease and I'll have time to make in-depth repairs. But I'll definitely look at them the first chance I get. I'm guessing these are hydraulic wet brakes, is there a inspection plug where the lining thickness can be checked?
 

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I doubt I'll be able to do anything to the brakes until winter, when operations cease and I'll have time to make in-depth repairs. But I'll definitely look at them the first chance I get. I'm guessing these are hydraulic wet brakes, is there a inspection plug where the lining thickness can be checked?
No, but the final drive can be taken down in minutes, to inspect and repair/replace parts.
 

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Discussion Starter #19 (Edited)
I should get the rockshaft cylinder seal kit today so I’m tearing the cylinder down now. I ordered a ball flex hone because there’s some longitudinal scoring in the cylinder, I figure a light honing should take care of everything.

DD84B330-3084-408B-B8AD-286428A20792.jpeg

My question is, to remove the lift/lower valves it looks like I press them in enough to pop out the retaining rings and they’ll fall right out. Yes/no? My service manual won’t be here for at least another week and I’d like to have this thing ready to work on the steering when it gets here. Thanks.

Disregard the valve question, they were a little sticky but they came out with a bit of tapping on the stems.
 

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Discussion Starter #20
After honing as much as I dared. Some of those scores were deep, but I think the O-ring will seal OK.

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