hydraulic problem

ribman · Mar 12, 2016

please help if u can. I bought a 1974 401b john deer tractor. the tractors front loader worked but did jerk while raising . the 3 point raised but never checked with weight . here is the deal. the hitch works great only when u undo the return line from loader . as soon as u attach the return line it is weak as water. ive by passed the remotes. still dosent matter. the loader jerks when raisng but is very strong . just cant use 3 point hitch with return line hooked up also the supply line seems to thump and pulsate all the time . ive put on new hoses and changed filter and fluid. no change please help if anyone can thank u so much

tim s · Mar 12, 2016

Unfortunately these are all normal problems with the Dubuque hydraulic system, they are very difficult to diagnose,,You will need to start with checking the basics,,sump screen, transmission pump flow, standby pressure, and of course the transmission filter. and with the filter some times the spring loaded 'cone' in the filter housing can stick to the old filter during a change and get tossed with out realizing it, then there is nothing to keep the new filter tight, oil flow will get it spinning in the bowl and let the rubber seal spin off and send it down the clean oil circuit clogging things along the way,, this is where you start...and as you go you will soon see why I don't care for this system...as I have said when they are good they are great,,,when they are bad they are very bad...

rrlund · Mar 12, 2016

What does it do if you turn the steering wheel all the way in one direction or the other and hold it there while you use the hydraulics?

ribman · Mar 12, 2016

Not sure. Haven't done that. It's crazy. I feel that fluid is pumping all the time based on the hose pulsating.

ribman · Mar 12, 2016

What are u thinking is wrong ?

rrlund · Mar 12, 2016

Spool in the power steering. It leaves an open circuit so the oil flows through it all the time like a bad leak. Holding the steering wheel all the way to the stop,stops the flow.

Tx Jim · Mar 13, 2016

Sounds as if frt end loader valve is leaking internally. With loader control valve levers in neutral no oil should exit FEL valve return hose. Does steering valve get hotter than other hyd components during operation?

ribman · Mar 13, 2016

Not sure. I do feel pump is pumping oil all the time
. The return has a quick connect so i will have to
take off to make sure

hydraulic problem

ribman

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tim s

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ribman

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