Pressure control valve, 4110

[JClark]

New thread on one topic from 'Power steering loosing power' thread.

Here is a closeup of the pressure control valve. The washer at the top, which I removed from the shaft for clarity, is the shim. This is what the mechanic called the 'thick shim', which replaced several 'thin shims'. He recalled the thin shims are .010" and each one adds 200#. I measured the thick shim to be .040".

 

[JClark]

Here is the parts diagram of the pressure control valve. This valve controls the maximum hydraulic pressure to the steering control valve and the selective control valve. The mechanic tells me there is a proportioning valve which maintains some minimum pressure to the steering control valve regardless of the demand of the selective control valve. Maybe that is what those two valves on either side othe the pressure control valve do. The parts diagram calls them safety valves.

 

[JClark]

This is the adapter they made for testing the pressure. The plug on the end (right side) is why I now have a nice shiny, unpainted plug on my tractor. It would be cheap and easy to make a pressure tester with a $15 gauge from Northern and a short nipple.

 

[JClark]

Here is front of the transaxle uncovered. Note the shiny plug.

Should I ever want or need to adjust the pressure, I now know what to do. The hardest part will be getting or making the necessary shims. I would not make any adjustments without a pressure tester though.

 

[nailerguy]

JClark, you should be able to purchase the shims through McMaster Carr. They are a industrial supply company that pretty much have some of everything. I have purchased many different sizes of arbor shims and smaller fixed O.D. X I.D. shims of many different thicknesses. I believe they even have metric sizes.

If you are interested, their Phone # is 1-732-329-3200. I call it so much I have it memorized /forums/images/graemlins/crazy.gif.

Very interesting diagrams and good pic's. The 2 cartridge valves could be counter balance valves that keep the steering from operating unless you turn the steering wheel. Just a guess on my part though.

I am glad your tractor is fixed now and I wonder if the dealer will keep a pressure test kit on hand now that they know why you had your problem?

Nailerguy