Farm Equipment - WD-45 hydraulics

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WD-45 hydraulics

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=181918
Printed Date: 01 Apr 2026 at 10:41pm
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Topic: WD-45 hydraulics

Posted By: allisbred
Subject: WD-45 hydraulics
Date Posted: 21 Jul 2021 at 7:38am

Can a pressure relief valve be plumbed into the hydraulic system to hold max pressure around 2500psi?

Replies:

Posted By: DrAllis
Date Posted: 21 Jul 2021 at 8:25am

Yes. You can just use a single-spool 2-way valve and then be able to operate a 2-way cylinder if needed. The lower pressure relief valve is already built into the 2-way valve. You could also make a relief valve that plugged into your existing outlet set for 2000-2500 psi to do the same thing. Either way, you'll have to have a return hose/line going back to the sump for the relived oil to find a place to go.

Posted By: allisbred
Date Posted: 21 Jul 2021 at 9:45am

Perfect. Do you recommend a location for the oil return? Thanks for the reply, Kevin

Posted By: Fred in Pa
Date Posted: 21 Jul 2021 at 12:12pm

Hyd. drain is easies place to put it , unless you want to drill a hole in top or side of housing .Where do u want your return hose laying

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He who dies with the most toys is,
nonetheless ,still dead.
If all else fails ,Read all that is PRINTED.

Posted By: Allis dave
Date Posted: 21 Jul 2021 at 2:54pm

If you have a transport valve on your 45, then you already have a return line that you can plumb into. Factory return line runs up near the dipstick if I remember correctly.

I just got a series III D17 and want to do just what Doc said. Put in a valve so I can run a 2-way cylinder. My D17 manual actually has this in the manual listed as an option. I bet the factory valves are pretty rare.

Posted By: allisbred
Date Posted: 21 Jul 2021 at 7:09pm

Fred in Pa wrote:

Hyd. drain is easies place to put it , unless you want to drill a hole in top or side of housing .Where do u want your return hose laying

I see someone added a nipple on the bottom at some point of life, do you think this would work or should dump in from top?

Posted By: allisbred
Date Posted: 21 Jul 2021 at 7:12pm

That might be to the transmission, I need to look at that again.

Posted By: allisbred
Date Posted: 21 Jul 2021 at 9:00pm

Allis dave wrote:

If you have a transport valve on your 45, then you already have a return line that you can plumb into. Factory return line runs up near the dipstick if I remember correctly.

I need to see if this one has it, I know there was a hold valve on another WD-45 we had. I remember forgetting to lock as a kid and the disc harrow grabbing some asphalt on the trip through town. This 45 drifts to the up position so I wouldn’t have to worry about it..🤓

Posted By: Allis dave
Date Posted: 22 Jul 2021 at 6:46am

The hold valve and transport valve are different. The hold valve is on top of the top.

The transport valve is at the rear of the tractor. The remote coupler screws into it. The transport valve will have a knob on it you can spin. No knob? No transport valve.