Farm Equipment - 7040 hydraulics

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7040 hydraulics

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=162007
Printed Date: 01 Apr 2026 at 2:41pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: 7040 hydraulics

Posted By: mike-mn
Subject: 7040 hydraulics
Date Posted: 18 Jun 2019 at 9:51am

Last fall my 7040 would not run enough standby pressure. It was around 200. It also leaks out of where the front cover bolts on the piston pump. It has leaked around 4 gallons in 3 weeks to a month of sitting. I checked the compensator for broken parts, but that looked good. I was going to just take the end of the pump off and reseal it ( do you have to take it off the tractor first), but was wondering if I need to look at something else to? I also question if it is leaking from the transmission, which would be orings on the next pump? Again thanks for any advice.

Replies:

Posted By: MACK
Date Posted: 18 Jun 2019 at 9:05pm

I would add some shims to low pressure compensator. I would pull the pump just to replace the gasket because they tend to leak as they age + all the lines will have to be unhooked any way. Pretty unusual for that gasket to leak. MACK

Posted By: mike-mn
Date Posted: 19 Jun 2019 at 9:55am

Does the gasket on the front plate have to be fiber or can I use Permatex? I changed the filters in the rear end and then it would run at 350 for awhile until I drove it.

Posted By: DrAllis
Date Posted: 19 Jun 2019 at 10:06am

Gasket is now a stamped steel gasket !! Pull all three pumps and get new Orings on the tranny pump to stop it seeping.