Farm Equipment - B Hydraulics

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B 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=139293
Printed Date: 17 Sep 2025 at 6:53pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: B Hydraulics

Posted By: Nat
Subject: B Hydraulics
Date Posted: 10 Jun 2017 at 9:24pm

I have a B Allis and it is the best B I have ever had and I've had several over the years. This one , starts, runs and does the best of any I have had but it has a problem. The lift. I converted it to 3 point hitch, and the geomentry of it is great, I used a CA cylinder and this isn't the first time I have done that. It works fine excep when I put the blade or landscape rake on it it will pick it up easily, and it holds it up and it doesen't slobber any fluid from the cylinder, but if I step on the blade to get on the seat my weight will push the lift to the ground. It doesn't leak there for it must be putting the fluid back into the housing. My guestion is do I have a valve leaking by or just where does the fluid go when my weight pushes the lift down. I have never taken a B valve apart and don't want to now but in the past when I converted a B to a 3 point hitch using a CA cylinderThe lift would raise the front of the tractor up if you put enough weight to counter the strength of the lift, not just colapse the cylinder. Do I have a valve problem or a pump problem or what? Thanks, Nat

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Nat

Replies:

Posted By: SteveC(NS)
Date Posted: 11 Jun 2017 at 6:00am

Any CA cylinders I have ever seen are single acting, so I would say you must have a leak in the valve on the pump assy.
In the up position the pump maintains pressure to the cyl.
In the hold pos. it just keeps it from returning to the pump/tank/diff.
In the down pos. it allows the fluid to return.
I'd say the valve needs a rebuild.

Posted By: Nat
Date Posted: 11 Jun 2017 at 7:21am

That is sort of what I was thinking. With th valve in the hold position , putting my weight on the implement will cause it to lower and since it id a one way cylinder and there is no fluid leaking from it then it stands to reason it is going back into the sump. My question is what can cause this to happen and a leaky valve seems to be the most likely culprit

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Nat

Posted By: PaulB
Date Posted: 11 Jun 2017 at 7:25am

Another thing may be that there is air in the cylinder. Those type cylinders need to be bleed by loosing the packing nut until oil comes out hen re-tighten the packing nut.

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If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY

Posted By: Bill Long
Date Posted: 11 Jun 2017 at 7:56am

We used to bleed them by loosening the connection to the cyl. with the implement down. We would raise it till a full stream of oil came out.
Worked for us in the old days.
Take good care of my favorite.
Good Luck!
Bill Long

Posted By: wfmurray
Date Posted: 11 Jun 2017 at 4:39pm

I have a B and have worked on pump .The relief valve is letting fluid pass when you put extra weight on lift .There is a plug on top of pump you can take out and bump relief barrel down and increase pressure.IT is real critical to adjust . Bump it down to much and pump has to be taken apart to get it back up.

Posted By: Nat
Date Posted: 30 Jun 2017 at 11:21am

I have been tied up and couldn't get back to the post or to the B. I have some time now but still don't know how to repair the valve. Any help apprecited
Thanks, Nat

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Nat