Atten: Owen Aaland and/or D. Slater

I need help diagnosing a problem with the Behlen power steering on my Farmall 400.

I bought a Farmall 400 on an estate auction. While I driving the tractor home after the sale, the power steering quit working after driving a couple of miles (after the tractor got warmed up). The next morning the power steering worked fine again (I could steer it with one finger), until the tractor got warmed up, then I lost the power steering again.

When the power steering quits, it works again "IF" one of the Hydra Touch levers is moved (doesn't make any difference which lever or which direction a lever is moved). After checking the archives here on YT, I figured the priority valve/flow devider for the power steering must be bad,... so I bought another priority valve off ebay,... it doesn't work either, even when the fluid is cool.
I called the seller on ebay and he said he knows "that" valve is good.

I'm sure the live-pump on the 400 is fine because it will pick up a 1500# round bale with the 3 pt., and I'm sure the Behlen motor is good because it works good when a Hydra Touch lever is moved.

I hope you fellas (or ANYONE for that matter) can help shed some light on what the problem might be,... I know absolutely nothing about trouble-shooting hydraulics.

Thanks,
Spotted Horse

Here is a picture of the valve bank, with the power steering priority valve/flow devider removed.

Get the tractor good and hot; to the point where the PS won't work.

Then, try to pick up your bale.

Allan

Have you pulled the flow divider spool out and looked at it. If it shows wear or erosion across the lands you can be sure this is the problem. These spools were available as of two years ago, but you need a savy parts man to come up with the number as they were originally a non service item. I would make a poor mans flow rater if I was checking it out. Hook a hose, a gauge ,then a restrictor valve , more hose on to outlet from valve, run it back into reservoir. Run tractor and restrict flow to about 7 or 800 psi,( should reach about 1200 psi fully restricted), then pull hose out of reservoir, put into bucket and measure flow for like 15 seconds, should get near a gallon. This will tell you if flow divider is or is not problem. Those valves can be rebuilt I am told, but that will cost you like 5 or 6 hundred I think. Caution, be careful of high pressure oil, it can kill you or make you sick enough to wish you were dead if it hits your skin and penetrates.

Allan, thanks for the reply. I've pretty much already done as you suggested.

A few days ago, I was moving round bales off one of my alfalfa fields,... after moving just 3 bales the PS quit working (again), I continued to move the remaining 30+ bales with the tractor.
While moving the remaining bales I had to also move one of the Hydra Touch levers when backing up to the row of bales (in order to get a reasonably straight row), and I had to move one of the levers when backing up to "stab" each individual bale out in the field.

The 3 pt. handled picking up all the 1500# bales with no problem, except I couldn't steer the tractor unless I moved a lever.

Moving 1500# bales with this tractor makes the front end pretty light (if I hit a bump, I can sometimes see a little daylight under one of the front tires, and that's with 200# of weight on the front ), and the tractor still won't steer decent even with the front end "fairly floating" across the field.

Thanks,
Spotted Horse

Pete 23,... The only thing I've pulled so far is the priority valve.
I'm not sure what you mean by a "spool",... is it one of the plug-looking things (with a hole in the center) that fits in one of the holes in the priority valve?

Thanks,
Spotted Horse

Yes, the spool is behind the plug with a snap ring on it. It is actally the priority valve and the rest of the components inside the valve block are regulator valve, relief valve, screen orfice and power steering relief valve. The lands in the bore where priority spool moves in can get worn also. I have not had a valve rebuilt but no doubt they will wear out with use and age, and have heard on this forum that there are machine shops that can rebuild them. When IH made this spool available for service it was a god sent as it made a lot of power steering systems work again without replacing the entire valve assembly. Some times, at this late stage, it does not do the trick though.

Pete 23 probably knows more than I do. Unless you can check pressures its hard to pin down the problem. Unless bought cheap I wouldn't buy a used priority regulator block unless they would take it back if there's a problem. Chances are a lot of used ones are no better than what you have. You still have a problem with the priority valve, or low pressure, a internal oil leak or also the steering unit is worn enough that it takes more oil flow than specs. to work good.
Sometimes the small hole in the priority piston will be found drilled out oversize to compensate for other problems.
If control valves were removed or installed you may also want to check that the oil passage plug is not damaged. Its located between the control valve for the rear lines and the steering control valve support post, in the lowest port. Pressure test would tell if it is holding with out disassembly though.

Thanks Pete and D. Slater,... you have given me some much needed info and things to check out over the next couple of days.

Thanks again,
Spotted Horse

Pete 23,... is this the spool you mentioned in your post below?

Thanks, Spotted Horse

Yup , that is is, doesn't look all that bad from here which doesn't hold a lot of hope that a new one would do the trick but no way to tell with out testing.

Pete 23,... Actually the valve/spool is in pretty bad shape (worse than it looks in the picture), it's "egg-shaped" or "out of round" by 4-6 thousands of an inch.

I made a trip to Kearney Nebr. this afternoon to see the Case/IH dealer. Parts man did find a number for the flow divider valve (#372204R1) but says it is currently a non-service item.

The IH parts man then sent me to a machinist, who looked at it and refered me on to a "CNC" machinist. The CNC machinist said he could make a valve for $150.00 but didn't have the tools (special jig) to hone out the "bore" of the flow divider/priority valve unit that the spool fits in.

Soooo,... I guess I'll give Steel Wheel Ranch a call and see what they have to offer.

I thank you for your replies, and I'll post back what STW has to say in case someone else has a simular problem with their Farmall 300/350 400/450.

Thanks again,
Spotted Horse