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Discussion Starter · #1 ·
When we first got the late model A the lift arms worked fine but gradually got where they wouldn't lift any weight. Now it's at the point where they don't lift at all. Then we recently bought a wood splitter that plugs into the remotes and it moves the cylinder but won't split anything large. It does still split small pieces of pine but not anything bigger. Should I be looking at the Power Trol or the hydraulic pump now?
 

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The leather cup around the piston is probably old and cracked. If I remember correctly, I took the whole back housing off to change it out. Mother Deere has the leather cups available.
 

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-Willy-
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The leather cup doesnt answer his low pressure on the wood splitter. Is the reservoir full? That is the first thing to check. I dont know about the A, yet my 60 has a domed pipe cap with a square tit on the top. You unscrew this and the hydraulic oil wants to be with in 1 inch of the top of the fill hole.
 

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Discussion Starter · #4 ·
It's got plenty of fluid. I'm thinking I may tear into it today. Bought the wood splitter to do some major clean up around the shop (or atleast that was my excuse) and now we've got to fix a ongoing problem with the tractor first. I should have torn into it a long time ago but am just scared of messing something up.
 

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Discussion Starter · #5 ·
Looks like whatever it is it's letting the fluid from the Power-Trol leak back into the tractor.
 

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-Willy-
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His pump may be weak. If it was run dry at anytime this would do it (prior owner). The pump is a set of gears that spin in a cavity with tight tolerances. A machine shop would probably shave a few thou off of the case to get the tolerances back up. That is unless it is shimmed, then it would only be a matter of removing a shim or two.
 

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Start with the simple things like the pressure relief valve, a broken spring here will let oil bypass pretty freely, end play on a gear pump has to be pretty big to make the hydraulics that weak at full rpm, at low rev it might bypass enough. the oil would also get hot pretty fast. for a spool to be worn enough to make things weak would mean major work to. Another possibility is the driven gear slipping on the pump shaft, but check the bypass first, the pump is big enough to open the bypass with the powertrol lever in up or down detent position (We work 2 cylinder JD tractors (AR s and 820) on our Ranch the hydraulics are lower pressure, but the AR will lift a newholland 489 haybine effectively and the 820 runs our Vermeer 605g pretty well, just need to block the chamber hydraulic lines with a diverter valve to keep the JD from dumping chamber pressure over bypass.
 

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As Johndeerefan said, there is a seal on the PTO shaft where it goes from the transmission to the pump housing that goes out and leaks pump oil back into the transmission. The hydraulic pump is run by the PTO shaft. The seal is cheap but getting to it isn’t easy.

Good luck with it.
 

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A far as I have seen , model A row crop type tractors have the powertrol pump rum off of the pto shaft, same pump as the powerlift. live hydraulics option, the pump was driven off of the mag or distributor drive. the AR/AO had a bigger pump driven off of the timing gears, this pump could be manually disengaged when not in use.
 

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JamieJ,

WoW! Stuff I didn't know.

Did you get if fixed? What did it take?
 

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We are having our plow days this weekend the second year I have used the newly restored 70. Yesterday the first day after about 4 1/2 hrs. out in the field noticed the plows once raised would not stay up eventually they would hardly raise so loaded up and drove home. During the restoration I went through the pump new bushings seal and lapped the housing surfaces, it has to be a bad check valve or weak pressure relief spring. The fluid level is correct so today will dive into it. Always look forward to plow days.
 

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Usually it is the lift cylinder has blow by
 

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I might tear into mine today. For now ruling out the lift cylinder since it was rebuilt during restoration. First thing to come apart will be the pressure relief valve then the check valve. No matter it will have to be repaired.
 

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the cylinder is the easiest to test, simply un couple the down coupler from the tractor end, remove the coupler from the hose, place the hose end firmly anchored in a clean 5 gallon pail (I like to use a hydraulic oil pail that is empty but still clean, if you put the hose in the spout there is less chance of splash) . start the tractor and attempt to lift the implement, if the implement does not lift but oil flows out the line in any volume the cylinder is the problem. the relief valve should not be in the circuit when the cylinder is in the hold position. a rapidly increasing failure usually indicates a seal failure rather than a lapped steel surface failure, surface failures are usually indicated by slow steady leakage
 

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Both check valves looked Okay as did the pressure relief so deeper I go. Before I start unbolting the castings will pull the valve off the tractor and see what the gasket looks like.
Appreciate the info Grizz after draining the Power Trol only had maybe a couple of quarts we know where that oil went. After I get the valve off plan to pressurize the feed port and see if I can hear air leaking.
 
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