3400 steering problems

69-3400

Member
Last winter I overhauled the steering sector because the tractor would not steer. I had to replace some parts and after I reassembled it the tractor still does not steer correctly. The steering works easy with the wheels off the ground but sitting stationary with the wheels on the ground it cannot be turned and is extremely hard to steer when moving (this is actually an improvement over what it was like before overhauling the sector). Today I connected a pressure gauge to the steering pump and got over 600 psi (should be 650 but the gauge was fluctuating) so now I am thinking about checking pressure at the steering sector but I do not know how much pressure should be at each port. I know fluid is passing through the sector and returning to the reservoir. Any additional advice or ideas are welcome.

Thanks,
Jeff
 
I'm going to assume you timed the sector gears properly and likewise assume your spindles have fresh grease and aren't all bound up.
600 psi is fine so your pump is good.
It's probably time to pull the steering wheel and cowel and go through the hydraulic block in the steering column.
They sometimes get full of gunk and rust and don't operate properly. Could also be caused by a broken spring in there too.
Replace both the upper and lower seals while you have it apart. Parts are available from CNH.
You will need an FO 31 manual to properly tighten and stake the nut above the hyd block on the steering shaft.
Sometimes guys forget which holes the plungers, balls and springs go back in the block. If you get in trouble we can help.
It isn't a hard job to do.
 
I should have mentioned I went through the block when I did the sector. There were issues in there too that had to be fixed. I pulled both lines to the left steering cylinder yesterday afternoon to see where and when I had pressure. One line has pressure while the other does not. The cylinder appears to be single acting because both lines connect to the rear of the cylinder, if I understand the intended flow correctly, they both should have pressure at the same time. Can you confirm or correct me on that?
 

No..its a push pull cyl..only one line should have pressure at time... the cyl is plumbed for the lines internally.


Question is.. did you over tighten the nut when in the steering box column. the unit must move up and down internally to allow the valve to select left or right. So the nut has a special tightning detail. and then you stake the nut so it will not loosen during normal use.

If one of the bearings is bad, the tractor will turn one way , but not the other. Same if over tightened..

If you got a spring or plunger messed up.. then.....
 
It steers easy off the ground; full travel both ways. If there was a torque value or procedure in the manual I used it (I am an aircraft mech and manuals and my regularly calibrated torque wrenches are my friends :) ) and I staked the nut. I replaced all bearings and seals from the top of the column to the bottom of the sector along with replacing any broken and/or questionable parts. Since the steering cylinders are dual acting then today I will check them for internal leakage.

Thank you,
Jeff
 

thinking aloud.....

steering off ground will NOT normally put enough pressure on the column to activate the power steering correctly,, so your free wheeling with NO power assist... with the selector in the neutral position...

Do you have one of your hydraulic lines reversed?
 
(quoted from post at 19:13:42 11/20/14)
thinking aloud.....

steering off ground will NOT normally put enough pressure on the column to activate the power steering correctly,, so your free wheeling with NO power assist... with the selector in the neutral position...

Do you have one of your hydraulic lines reversed?

That is a possibility I will have to check out. I have been working off the assumption I have power with the wheels on or off the ground. I know the left side is plumbed according to the book and has been verified correct by watching the flow but the book doesn't show the right side and I have not opened those lines to check flow. If it is a mirror of the left side then it is correctly plumbed (the rear port on the valve is connected to outside port on the cylinder). When I pulled the column last winter I labeled the lines so I would not mix them up but that doesn't mean they weren't already wrong.

Thanks,
Jeff
 
Anyone ever see one of these steering systems generate it's own air? I couldn't seem to get the system bled using the procedure in the book so I cracked lines at the cylinders one at a time and applied pressure to the open line to bleed and fill the cylinders. Afterwards I started to get some action with the cylinders but the oil is very foamy. Foamy to the point it overflowed the reservoir (squirted oil 20 feet through the vent hole in the cap). The reservoir is currently full of foam. I had noticed the foam before but figured it was because I hadn't put enough effort into bleeding the air out. I am not so sure anymore and foam is nearly impossible to bleed out of a system since it just keeps circulating. The only fluid leak I see is on a cylinder rod but it isn't dripping even with pressure applied to it.

Thanks,
Jeff
 

filter MUST be in place and in good condition in the reservoir...It will stop the bubbles.. fill it... cycle the steering, fill it again.. cycle then it should be full or nearly full.

Just went through a 3400 that I sold last month with a loader on it. replaced a leaking cyl and bad pump... Took two try's to get the reservoir near full.. then it settled down.
 
Thanks guys, I will pull the filter and see what it looks like. I can't remember if I changed it last winter or not so the odds favor "not".
 

Dont strip the bolt that holds the cover on the reservoir.. its easy to do... btdi.... several times... If cover is slow to go on.. tap with rubber hammer.. but the bolt will strip the aluminum pump if you put the least extra pressure on it...
 
Okay, I replaced the steering filter, and bled the system. NO CHANGE. Still foamy and still no steering with the front end on the ground. When bled, the cylinders do move the correct direction without putting enough force on the steering wheel to actually move the wheels. This happens with about half the weight of the front end on the ground. As soon as I raise the bucket, the ability to steer ends. I backed it out of the barn twice today to see about steering it on the move and the results weren't much better than sitting still.

Please keep the ideas coming. I need to get it fixed or sell it and get one that I can use.
Jeff
 
I finally broke down and ordered a steering pump. When I pulled the pump supply line loose a at the reservoir, I found the line plugged with an old dipstick and a gasket. I reconnected the lines and I now have limited steering with weight on the front wheels. The oil is still foamy so I am drawing air somewhere and will most likely still need to change the pump to get my steering fully operational.
 

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