Farm Equipment - Hydraulic pump

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Hydraulic pump

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=156961
Printed Date: 05 Sep 2025 at 5:03pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Hydraulic pump

Posted By: Jaime
Subject: Hydraulic pump
Date Posted: 05 Jan 2019 at 7:11pm

I have a 59 D17 I use to bush hog a couple of small pastures. The lift arms are constantly dropping. Has anyone rebuilt or done work on one of these hydraulic units?

Replies:

Posted By: DrAllis
Date Posted: 05 Jan 2019 at 7:32pm

If you are having hydraulic oil disappear and the transmission gaining oil, you have an internal leak inside the lift arm housing. (Hydraulic oil is under the gas tank on the RIGHT side. The transmission oil is to the RIGHT of the gearshift.) Either a hydraulic hose or packing in the lift cylinder is leaking, both of which need to be replaced when repairing. If your oil levels are staying where they belong, the hold valve inside the hydraulic pump must be leaking off. I'm not so sure you couldn't devise two chains to control the down working height of the mower and not depend on the hydraulic pump to do it. This would be in lieu of fixing the pump.

Posted By: Jaime
Date Posted: 05 Jan 2019 at 8:13pm

Thank you for your response. I’ll check the fluids before I run it next time. I always have to check them anyway since it has leaks. Power steering is the main leaker, but I’ll monitor the Trans levels a little closer, maybe I’ll be able to pinpoint the problem. Which one of those problems would you think is most common.
Thanks again.

Posted By: Jaime
Date Posted: 05 Jan 2019 at 8:19pm

Posted By: DrAllis
Date Posted: 06 Jan 2019 at 6:49am

Losing hydraulic oil into the transmission compartment. Doesn't sound like that is the problem because if it transfers enough hyd oil to the trans, the hydraulic pump will eventually quit lifting because it is empty.

Posted By: Clay
Date Posted: 06 Jan 2019 at 3:07pm

There is a high pressure hydraulic hose inside the rear of the tractor. It is accessed by removing the lift arm housing.

When this hose ruptures, it will allow hydraulic oil to be pumped into the gears. Easily detected by an increase of oil level in the gear box.

DO NOT buy a run of the mill replacement hose. Purchase one from AGCO. This is a very high pressure hose.

The hose will have a stripe down the length of the hose.

It is IMPERATIVE the strip remains straight. DO NOT allow the hose to TWIST.

I have replaced these hoses by myself but is much easier with a helper.

Posted By: Jaime
Date Posted: 06 Jan 2019 at 10:06pm

Thank you guys you have given me some good advice. I will report back in the spring when I get back to using it again. Im also going to take a closer look at the power steering leaks. It’s getting to the point that just filling it up may not be cost effective.
This old guy can still do a days work and not even break a sweat. Got to keep him repaired.

Thanks again
Jaime