Farm Equipment - hydraulics question

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hydraulics question

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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=21875
Printed Date: 12 Feb 2025 at 12:17pm
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Topic: hydraulics question

Posted By: DWC17
Subject: hydraulics question
Date Posted: 06 Dec 2010 at 3:31pm

I put a front mounted hyd. pump on my D-17 and now when I lower the loader or dump the bucket the tractor motor labors and after one or two cycles the pump is HOT!!. Raising the loader or tipping the bucket back, the tractor motor does not labor.The pump is off of a Gleaner F and I'm running 1/2" hose to and from the pump. The reservoir tank is off of a "F" also and it is mounted above the pump. I have T.S.C.s equivalent of Allis 821 oil in the system. Any help would be appreciated.

Dan

Replies:

Posted By: Dakota Dave
Date Posted: 06 Dec 2010 at 3:35pm

You are deadheading the pump. check for configuration on your control valves.

Posted By: DWC17
Date Posted: 06 Dec 2010 at 3:49pm

Sorry but I'm not too bright when it comes to hydraulics. (my wife would say that hydraulics wasn't the only thing) Could you please elaborate more on what "deadheading the pump" means? Also what do I need to check on the configuration of the valves.

Posted By: jaybmiller
Date Posted: 06 Dec 2010 at 4:09pm

Deahheading means you're drawing oil from the reservoir,sucking it into the pump but the hi pressure hose from the pump has nowhere for the oil to go due to the valve being 'closed center'

kinda like having to sneeze while holding your nose and mouth closed...very painful !

You need 'open center' valves that allow the oil to flow back to the reservoir if not going to a cylinder.

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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Posted By: DWC17
Date Posted: 06 Dec 2010 at 4:35pm

I originally had it hooked up to the tractor hyd. reservoir and I didn't have any problem with the pump getting hot but it did seem to cavitate with having to draw the oil from below the pump. The valves on the loader worked fine until I hooked it up to the external tank. I also noticed that when I push the lever (to lower the loader) all the way forward, the loader wants to raise.

Dan

Posted By: Dakota Dave
Date Posted: 06 Dec 2010 at 7:43pm

You need to have a return line from the center of you valve going back to the resevior. when you go to lower both the bypass fluid and the return from the actuator need a place to go. I don't know what valves you are using but the pump must always have a place for the fluid to go. If youve ganged your returns it is to small for the flow and the fluid is taking the path of least resistance. You pump return is probaly overpowering your return fulid and raising the loader.

Posted By: DWC17
Date Posted: 07 Dec 2010 at 4:27pm

Thanks for all the help, it got me to thinking about some of the lines I put on it. I ckecked it out today and the one swivel I had put on the return line was holding back most of the fluid. I removed the swivel and the loader works fine. Thanks again for the responses.

Dan

Posted By: CTuckerNWIL
Date Posted: 07 Dec 2010 at 4:47pm

Good deal.

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Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF