770 hydraulics

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770 hydraulics

Postby Adustydoo » Mon Jan 11, 2016 4:25 pm

I have a late model 770 with a loader .Several years ago I added a remote valve and tapped into the hydraulics power beyond port . I also added a remote reservoir because loader would drain the system when raised very high.I have always had a problem with the tractor overflowing the hydraulic oil after lowering the highlift ,or shutting off the tractor .Last winter I decided to take a look at the pump to see if anything looks abnormal.There was very slight wear on the end plates . But there was some scoring on the ends of the gears and the center plate.I decided to live with the problem and put everything back together . Now I a problem with oil foaming and very slow lift on loader arms .and the oil foams and overflows a lot more than ever I have the pump out again and everything looks like it did before.Any ideas would be great Ray
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Postby John Schwiebert » Tue Jan 12, 2016 4:51 pm

Send me a P M in the next day or 2 with your phone number
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Postby Adustydoo » Wed Jan 13, 2016 2:32 pm

Pm Sent thanks
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Postby Nick F » Fri Jan 15, 2016 5:56 pm

The oil cannot gt to the reservoir as fast as it come back from the loader when you let it down. The solution is plumb the bottom and the top of the hydraulic unit to the reservoir.
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Postby Adustydoo » Fri Jan 15, 2016 9:20 pm

Thanks Nick that is similar to the way i have mine plumbed !What is to the rear of your remote reservoir,it appears to be a filter? What i have done in the last couple days is removed PTO shaft and removed entire hydraulic unit. I then unbolted the pump an reinstalled pto shaft with pump .Then made mount brackets and homemade fitting plate 1" inlet from a 5 gallon reservoir and 3/4" outlet to a pail then started tractor and let run for 30 seconds and had dad watch oil from pump .In 30 seconds we had heavy flow of very foamy oil about 8" up a five gallon bucket,But when foam settled only had about a quart of oil . I believe bearings are wore enough that can push gears under pressure out to center plate .May also have seals allowing air to be pulled in on vacuum side of pump. I will now find and replace hydraulic pump .I sure hope this resolves all my issues
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Postby Nick F » Sat Jan 16, 2016 6:59 am

Many years ago we had an issue with that hydraulic system and installed that filter on the return from the loader valve to clean up the oil. We just never took it off.
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