[dogsled]

I have a 1975(?)JD 400 that recently developed a crack in one of the hydraulic oil lines. I replaced the cracked line with a new line from the dealer. I drove it around the yard for a good half hour raking the yard with a 3-point attachment. Steering gradually became very stiff to turn in either direction and the 3-point attachment began to hesitate and pause while lifting. I’m leaning towards issues with the control valve, but would like to rule out any and all other possibilities. I’m somewhat of a novice when it comes to this tractor. Any advice?

 

[jdmaninlouky]

Zed -

Check the fluid . Top it off if needed . Look for leaks . That's all I got . Good luck ; and welcome to WFM Zed ! Although I seem to remember your name on here before . Did you have to re-sign up ?

Dave

 

[T-Mo]

Moved to proper forum.

 

[sreynolds]

It is in the manual. I'd have to look it up. Pretty simple test, but obviously, one would have to obtain the test equipment from a local supplier like NAPA.

I will take a look for you.

 

[sreynolds]

Wrong fluid
Dirty fluid and/or filter
Air leak into supply side
Worn pump

....install gauge into any hyd circuit port. (obviously you use a quick coupling and a short section of hose) Operate engine at WOT and activate the proper circuit lever. 650-750 psi

 

[jdalchemist]

Zed,
Along with checking the fluid level, a first simple thing to try is moving all three hydraulic control levers to be sure a spool is not stuck at its limit. A stuck control valve spool will give these symptoms. How is the tractor ground speed?
Harold

 

[dogsled]

-Everyone,
Thanks for all your advice!
I'll get started trying your suggestions tomorrow after work.
I’ll let you know how it goes.

Zed