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MrBrowner

4040 Hydraulics Question.....

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UCD
Low pump pressure, low pump volume, weak pressure relief valve, plugged filter, Leaking O rings in control valve, obstructed hydraulic lines, Leaking O rings/seals in hydraulic cylinder.

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JP
To add to your selection.... Worn drive belts, seized clutch pivot bushing, Incorrect clutch spring tension. I think between this & Maynard's list outta cover it (LOL). Let us know how it turns out! (Sort of like "Stump the Chumps" on the NPR radio show "Car Talk" with Click & Clack, the Tappet Brothers) (Don't Drive like my brother!) (LOL)

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MrBrowner
Transmission works good. Hydraulic cylinder doesn't leak oil. Just changed trans. oil & filter. cylinder hoses are about four years old. Is that a good sign, that pump pressure, volume and pressure releif valve are good if trans. works good? What do I need to do, take off cylinder hoses one at a time, and put a gauge on them? Will this tell me anything? What should the pressure be if I do this?

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cranemech
Evening, Is the cylinder slow both directions?Any difference with a load or no load? Do you have any problems with the cylinder lifting a load (other than being slow)? Volume of oil = speed of ram Pressure of oil = lifting ability. Check to make sure control valve is being fully stroked. Later, Chad

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MPH
On the front left side of the tranny unit is a pipe plug, this is where you screw in the gauge to check your pressure. You need a gauge that reads at least 1000 psi and should be liquid filled. With engine running close to full speed your 'charge relief' pressure should be 70-150psi. When you activate the implement lift lever it should read 700-800 psi. If you have a manual its on page 2-41. Mine was giving me the same problems, my guess is my charge pump is worn/weak or I was told it could be slipping inside ie, sheared key. Haven't been able to go into it that deep yet. My charge and implement relief valves appear to be ok, granted, to an untrained eye. I did break the book rules and added a shim behind the springs which brought me up to almost half pressure.

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arnoldir
I see filter was changed, what type ? Fram extra guard oil filters will starve the charge pump and cause slow/weak hydro lift. On this machine the hydro filter is on the suction side of the pump and should be no finer than 25 micron mesh as per Simplicity. I bought a 720 that could not lift a box blade, or climb a small curb in 1st gear. Put an OEM Simp filter on it and it became a usable tractor.

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