Farm Equipment - L3 hydraulic pressure

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L3 hydraulic pressure

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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=197269
Printed Date: 25 Sep 2024 at 7:23am
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Topic: L3 hydraulic pressure

Posted By: 8070nc
Subject: L3 hydraulic pressure
Date Posted: 19 Sep 2023 at 5:45pm

Can any one tell me how to increase the hydraulic pressure on a l3 combine. I only have 1600 psi and itwont raise the header. I have a service manual ordered from agco but havent recieved it yet

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Replies:

Posted By: DrAllis
Date Posted: 19 Sep 2023 at 6:42pm

If you start the engine cold, throttle it up and try and lift the head, does it lift the head with cold hydraulic oil?? If so, I'll bet your hydraulic pump has issues, meaning turning up the pressure ain't gonna happen.

Posted By: 8070nc
Date Posted: 19 Sep 2023 at 7:45pm

Cold oil doesnt make any difference. I put a pressure guage on the header lift circuit and only have 1600 pounds. Its probably the pump I agree I found the relief valve. I want to get some shims to set it up before I get into changing the pump
Thank you. I appreiate your help

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Posted By: 8070nc
Date Posted: 19 Sep 2023 at 7:51pm

I want to clarify a little. The only way i know of to see if its the pump is shim the relief valve. If pressure doesnt increase I know its the pump. If theres another way ill be glad to do it

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Posted By: SteveM C/IL
Date Posted: 20 Sep 2023 at 9:18pm

When the wear plates get worn and the back up rubbers get old they don't make the pressure. I doub't shimming relief will change much .

Posted By: tbran
Date Posted: 20 Sep 2023 at 10:20pm

You can try - remove the metal cap from the relief valve on the MAster Valve , if it has one - the valve slice on the front end with only one coil. Loosen the jam nut and screw in.

https://parts.agcocorp.com/us/en/apbsearch?q=gleaner/79006820/l&name=L3+%28EFF+S%2FN+28001%29+%2F+M3+%28EFF+S%2FN+25901%29+COMBINE" rel="nofollow - https://parts.agcocorp.com/us/en/apbsearch?q=gleaner/79006820/l&name=L3+%28EFF+S%2FN+28001%29+%2F+M3+%28EFF+S%2FN+25901%29+COMBINE

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When told "it's not the money,it's the principle", remember, it's always the money..

Posted By: robb
Date Posted: 21 Sep 2023 at 7:27am

Are you sure your belt is tight or not worn driving the Hdy pump? If its slipping the pump will not make enough pressure to raise the header.

Posted By: 8070nc
Date Posted: 21 Sep 2023 at 8:56am

Thanks for the replys
If theres arelief valve on the master valve I cant find it
I put a new belt on it
I had a pressure guage on the header lift circuit so it was deadheading and it loaded the engine substantially even wide open so I dont think the belt is slipping. I have a more pressing problem now. I took a cap off of what turned out to be the priority valve thinking it might be the relief. Put it back in thinking I had it back just like it was now no steering
It will pick up the bean head. Ive got to figure out this priority valve now ill content with header lift later

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Posted By: Ray54
Date Posted: 21 Sep 2023 at 2:41pm

I have seen header lift very much slowed down on MH2's by a spring breaking inside the electric control valve. Pieces would jam the little steel bb in side it. Just guessing, but L and F series Gleaner all used the same type electric controlled hydraulic valves?

Another it should of never happened but did, is the weld on the header lift cylinder failed at the fitting. It was about 15 years old and 5000 hours. Why that long and all of a sudden fail.

I would check the pressure in another circuit before replacing pump. Another thought that others can say more about, because I could be wrong. Is it possible the wiring or magnet is going bad and not opening the valve up to give full pressure?