John Deere 1640 Strange Hydraulic Problem

[Jimbo1640]

Hi Everyone-

Been having the weirdest problems with the hydraulics on my 1640 and have finally determined that we only have hydraulic oil pressure when the rockshaft lever is in the raised position. Have now determined (due to an oil pressure gauge installed off a port on the hydraulic pump) that it doesn't matter what position the selector lever is in (Lift or Load or in between), when the 3 point hitch rockshaft lever is lowered the pressure drops. Midway you have 1/2 pressure, all the way down you have nothing--no power steering, FEL, nothing.

Does any of this ring a bell or sound familiar?

I can get into taking the top off the rockshaft housing but I kinda need a direction to go in here to see what I should be looking for. Any suggestions or ideas are appreciated. Cheers.

 

[Tx Jim]

My 1st thought would be to perform the L/D control adjustment procedures described in length in your tractors JD tech manual. My next guess is clearance on mechanism that controls the valves isn't set to correct clearances on the pressure & return valves but this would be addressed if my 1st statement is adhered to. I've witnessed breaking of the cam follower or spring under rockshaft housing causing 3 pt control problems.

 

[Jimbo1640]

Tx Jim-- Thanks so much for the reply and a big hello to Coyote Flats (wonderful name). Will go through the L/D control adjustments as suggested (this is on paragraphs 167-171 of my I&T JD Shop Manual under the section for the 2040). I'll start there. Cheers.

 

[Tx Jim]

You're welcome
My plan was to live in the country when I "passed on" but my neighbors in 2010 voted me into the boundaries of a newly formed city with a population of 342. :laughing:

 

[Zebrafive]

You should run for Mayor/Dog Catcher

 

[Tx Jim]

I can't run for dog catcher because this city only has a mayor & 3 council members with no other officials but no ordinances,city laws other than county/state laws or city TAXES at this time.

 

[Zebrafive]

You should suggest they need a Dog catcher, so they have five members and can then never have any tie votes.

 

[Jimbo1640]

Ha! Well, it still sounds a bit like the middle of nowhere, which is how I like it.

 

[Jimbo1640]

Tx Jim-- Ok. Was impossible to complete the L/D controls setup past setting up and verifying the Negative Stop Screw. When I went to the next step, Depth Control Neutral Range with the Selector in the upper "D" position, rockshaft in lower, upon engine startup the lift arms raised about 1/3 and the quadrant lever went up with it. The only way I could get the arms to lower was to put the selector in the lower "L" position, then they would lower. I put the Selector back in D, lowered the quadrant lever and shut off the tractor and they lowered.
When I cranked 'er up again observing carefully, same thing, arms raised and took the quadrant lever with it.
The port hole for the adjusting screw seemed to have a consistent spray of oil that was trying to come through it. I looked in the filler hole and there seemed to be a bit of a water sprinkler thing going on in there with hydraulic oil. Memory plays tricks on me, but I don't remember seeing that before, quite a bit best I could see with a pen light.
That's where I'm at now, kinda dead in the water. Wondering about seals in the rockshaft cylinder.
Any thoughts are appreciated.

 

[DLTTrekkers]

To see if it is some adjustments.
Look at rightside of hidge and find a plug that you can unscrew with a t- handle ...inside you will see a screw. Screw that in with a screwdriver to widen the neutral range and see if the spray at the back lessen or stop.
You can test that by moving the lever just a little up and down and see if the arms lower and lift just a little.
All those models have a problem with blowing the o-rings on that valves.