Hydrailic Pump (gear)shouid I have to rev all the way

cmcgalla · Sep 18, 2018

Hello, I have a gear pump that drives my front loader and backhoe on my 1957 MM 445I, but not at the same time. The tractor was born the pump, I have put in new needle bearings.

In order for me to get max power I have to throttle all the way up. If I am picking up a roundbale at half speed it will not do it, I have go wide open. Is this normal?

I though that running at high RPM would only change the flow rate (GPM) and the pressure (PSI).

Can somebody set me straight? I have been thinking about this for a while and since I have been home sick for 2 days I figured I would use the time wisely....

Thanks
Zeek

Steve@Advance · Sep 18, 2018

In a perfect world, yes, it should work at low speed, but be slow.

What's happening is there is fluid loss somewhere. It can be a worn pump, a leaking bypass valve, a cylinder leaking internally, or a directional valve not centering. Some have a valve that directs hydraulic power to the 3 point, the back hoe, or the loader. If it is not in position or leaking internally it could loose pressure.

It can be a challenge to locate the pro
blem, and hydraulics are too expensive to throw parts at.

If you raise the loader, and let go of the valve, will it stay up? If yes, the cylinder seals and directional valve are good.

When the bearing were replaced in the pump, was the housing bore to gear clearance, and the gear end clearance checked? If the bearings failed, the gears could have damaged the housing. That may be a good place to look first.

J. Schwiebert · Sep 18, 2018

Do you have say a 2000 PSI pressure gauge? You need to check the pressure in the system to start with. See what that is then tell us and we can help you trouble shoot the problem.

JK2 · Sep 18, 2018

Is this an Ottowa (sp) LX loader/backhoe?
If it is, there is a pressure regulating valve located in the loader control valve that has o-rings on it that go bad or even disappear completely causing what you are seeing.
If I remember correctly it is closest to the hood on the tractor.
When those o-rings are leaking, the pump has to overcome the leakage before pressure is developed in the system.

cmcgalla · Sep 19, 2018

(quoted from post at 02:56:33 09/19/18) Do you have say a 2000 PSI pressure gauge? You need to check the pressure in the system to start with. See what that is then tell us and we can help you trouble shoot the problem.

Duh..I should have thought of that, thatnks. Yes I have one and will check when I can and report back.

cmcgalla · Sep 19, 2018

No the loader and backhoe are made by Shawnee and they are out of business.

cmcgalla · Sep 19, 2018

(quoted from post at 01:58:58 09/19/18) In a perfect world, yes, it should work at low speed, but be slow.

What's happening is there is fluid loss somewhere. It can be a worn pump, a leaking bypass valve, a cylinder leaking internally, or a directional valve not centering. Some have a valve that directs hydraulic power to the 3 point, the back hoe, or the loader. If it is not in position or leaking internally it could loose pressure.
[color=red:b7cae6f81b]
It could be the selector that changes the flow to front loader and backhoe. If that were true then some fluid be in the loader when I am digging with the hoe, right? There is no 3 point on this machine.[/color:b7cae6f81b]

It can be a challenge to locate the pro
blem, and hydraulics are too expensive to throw parts at.

If you raise the loader, and let go of the valve, will it stay up? If yes, the cylinder seals and directional valve are good.

[color=red:b7cae6f81b]Cylinders have all been rebuilt recently and hold just fine.[/color:b7cae6f81b]

When the bearing were replaced in the pump, was the housing bore to gear clearance, and the gear end clearance checked? If the bearings failed, the gears could have damaged the housing. That may be a good place to look first.

[color=red:b7cae6f81b]No I did know that was something to do, can I get the real specs from the manual? Bearing never failed.[/color:b7cae6f81b]

Alaric · Sep 3, 2021

I saw you had asked about the weight of your Shawnee HD-8A Loader and Warrior D80 Backhoe some time ago, If you are still interested according to a 1959 price sheet I have the HD-8A Loader had a shipping weight of 900 lbs and a price of $565, I don't have a listing for the D80 at the moment but have more price lists on the way so I may soon.

I have a 1959 Fordson Power Major with a Shawnee Loadmaster LM-1A Loader and a Chief D90 Backhoe, The backhoe is missing the lower boom and I've been collecting pictures and literature in an attempt to gather enough information to fabricate an replacement that matches the original. Based on all the information I have so far the D80 Warrior and the D90 Chief are very similar, Any chance you would be willing to take some pictures and measurements of your backhoe for me?

I tried to post this as a response to the original post but it is to old and PM is not available so I posted it here in hopes you would see it.

Thanks,

Richard

Hydrailic Pump (gear)shouid I have to rev all the way

cmcgalla

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Steve@Advance

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J. Schwiebert

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JK2

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cmcgalla

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cmcgalla

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cmcgalla

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Alaric

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