Loader 300CX Loader John Deere 4400 tractor

[RoyJackson]

Not a chance...the PS system is completely separate from the rest of the system except for the common sump.

Thanks, Kenny! At least that eliminated one possibility.

 

[bramleyestate]

Thanks for the updates so far.
I have tried disconnecting the hydraulic ram from the front axle, the power steering is still heavy and reluctant to move, though it does at high revs. The ram appears to be a sealed unit, slightly marked (black) in the middle of the chrome area.? Does the PS have a seperate oil reservoir that could be low of oil, or its own filter that might need changing? Someone stated it uses a seperate pump, but I have not been able to locate this.
Many thanks again for all your help jules

 

[beenthere]

Same reservoir (sump) as mentioned. Dual pumps are in line on left side of engine.

jdparts can show you some of the schematics and part layout for isolating places to check out and identify some of the parts found.

 

[Mechanos]

...slightly marked (black) in the middle of the chrome area.? ...

That could be from a bent rod on the PS cylinder. That would definately account for resistance to steering.

 

[bramleyestate]

Update, I have now changed the hydraulic oil and replaced the and cleaned the filters. However this has had no effect on the power steering, it is still heavy, some time I am sure it is worse than other times, but always requiring high engine revs. I have also experienced the front loader locking in the down position, which I believe to be caused by a faulty quick coupler, but cannot explain why it does it, as I keep them connected, so dont know how it could lock up, but i disconnect it tap the end to release a bit of pressure, then it works again!!
I have to say, I don't like this tractor anything like my old yanmar, although it does have more power and cuts the grass well. I wish I had the manual gearbox and light power steering!