JD300B Rockshaft leak

MichelD · Sep 1, 2019

Hello to all,

I have a 1983 JD300B with 3pt hitch that will lift implements but will often need to be jerked or manually helped to do so. I looked through the Hydraulic fill cap hole and can see spraying oil from the top, if I jerk the lift harms manually,the implement lifts very well and the spray stops at the same time. Do I need to replace all the seals in the control valve or can something else more accessible cause this behavior? I have the shop manual for the tractor and can see all the seals in the assembly, it would be great if I could be pointed in the right direction to target the right seals. Last, are parts for this work still available?
Many thanks

beenthere · Sep 1, 2019

This TBN thread may help you.
https://www.tractorbynet.com/forums/john-deere-ag-tractors/220429-1520-3pt-valve-leaking-help-2.html

And member Tx Jim may come along and be of some better help for the problem.

Also, you can look up part numbers using the JD part site.
https://partscatalog.deere.com/jdrc/

MichelD · Sep 2, 2019

Hello Beenthere,
Thanks for your quick reply, yes this thread is helpful, is the rockshaft assembly in the 1520 same as in my 300B? Because of the roll bar I can't bring the tractor in the shop as it doesn't fit through the door, how heavy is the rockshaft assembly? I can rig a hoist on the roll bar to lift the assembly but will need to move it by hand after.
What would be your best guess as to where the leak could be given that the oil spray stops when the arms are lifting the implements?

Tx Jim · Sep 2, 2019

Sounds as if seals on rockshaft control valves are leaking which to repair requires R&R of rockshaft housing. Yes 1520 & 300B rockshaft housings are alike. I think you'll need some type of lift to handle RS housing especially when re-installing.

MichelD · Sep 3, 2019

Hello Tx Jim,

Thank you for your reply, I am ordering the parts now and wonder if it is worth replacing the sleeves (#T24540) as well as all the seals.