Farm Equipment - Hydraulic problem

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Hydraulic problem

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=189605
Printed Date: 07 Sep 2025 at 3:30am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Hydraulic problem

Posted By: Lyle
Subject: Hydraulic problem
Date Posted: 20 Jul 2022 at 9:32am

Late model Allis 200, getting over100lbs more on the pto valve than on the power director valve. Is there a solution?

Replies:

Posted By: DrAllis
Date Posted: 20 Jul 2022 at 9:36am

100 lbs versus zero pounds?? or 300 versus 100 ?? Why are you concerned?? what problems are you having?? Pressure is controlled at the Power Director valve and could be a little higher upstream from it. 100 pounds with PTO engaged?? PTO off? PTO in the neutral/coast position??

Posted By: Lyle
Date Posted: 20 Jul 2022 at 3:31pm

450 psi on pto and 300 psi on power director. Didn’t matter what position the pto was in. If the power director put in neutral pto pressure went up to 500 psi at 1600 rpm’s.

Posted By: DrAllis
Date Posted: 20 Jul 2022 at 8:00pm

You don't say, but I assume your s/n is less the 4001, which has a big round ball on top of the Power Director handle. If this is true, your PTO valve has a pressure regulator in it and it must be stuck. Located underneath the hex plug that doesn't line up with the control spool. The internal spool is stuck in the valve body. Three main pieces: spool, plunger and spring with shims in the hex cap.

Posted By: Alex09(WI)
Date Posted: 20 Jul 2022 at 8:22pm

Dr - he has a 200 after serial #4001.

Lyle- try to explain with as much detail as possible, such as which ports you were measuring the pressure, and in what positions the power director and PTO valves were in.

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Posted By: Lyle
Date Posted: 21 Jul 2022 at 8:53am

Top 1/4” plug closest to the control rod on the pto valve pressure stays the same engaged or not engaged. the power director using the low side 1/4” plug on the valve closest to the front of tractor. I was checking them with both valves engaged. The pressure goes up on the pto valve 90lbs if I put the power director in neutral. All of this is at 1600 rpms. If I idle the tractor, pressure runs at 200 on the pto valve.

Posted By: DrAllis
Date Posted: 21 Jul 2022 at 9:03am

What kind of problems are you experiencing ??

Posted By: Lyle
Date Posted: 21 Jul 2022 at 9:29am

I can’t maintain pressure at 295 to 320 on both power director and pto clutch. Power director is at 300, then pto is at 450 to 500 psi. I misspoke, it’s 1/8” plug not 1/4”.