[drozment]

Thanks for the info. That valve doesn't seem to be leaking. Any way to check to be sure that's what the problem is?
And also, when I lift the front off the ground so that there is no weight on the front wheels, it does not vibrate.
The vibration is only when turned all the way to the right, no vibration when turned to the left side.

 

[drozment]

Thanks to every body for the advice, I think I'm going to replace tie rod ends, spindle bushings and the steering cylinder.
All these seem to have a good bit of wear in them. I'll let you know if it helps. If not then I''ll try something else.
Thanks to all

 

[drozment]

Hello Gentlemen, I finished this 420 up a while back, but something is still not exactly right. I replaced all the tie rod ends, steering cylinder etc. All movement is smooth. But there is still a vibration in the whole machine when steering, ie when the hydraulics are
attempting to move the wheels. Someone mentioned that maybe its the steering valve. I have not replaced or rebuilt that yet. It is
not leaking externally, but maybe internally? Would that cause the problem?
Also, I have of course changed all fluids and filters on the hydrostat and replaced all the worn parts, even the gas cylinder in the linkage, but this thing
is extremely jumpy when starting off. Runs fine once you get going, but starting and stopping I have to hold on. Could theses issues be related?
Something in the hydro pump? Any ideas from the experts is appreciated?

 

[drozment]

Did you go through the creep adjustment? That has some part in the jumpiness issue. There are 4 versions of the control linkage system, which version do you have?

Now that you have taken care of the other issues that affect steering, it looks like the other bad news is that you will have to pull the steering valve and do tear down and rebuild.

Well, I thought I had followed the TM instructions for getting the creep out. Evidently I missed something. I will go back into it and see what I missed.
I did replace several parts that were worn. And I'm not sure which version of the linkage it has. It has been a couple years since I did the original work.
It would be good if that is what is causing the jumpiness. I was afraid it was something internal in the hydro or pump.
You are the second to suggest that the steering valve is the issue, so I guess I'm going to need to replace or repair that. Not looking forward to that.
It seems like a bear to remove. Is that something that a local hydraulic shop would probably rebuild? I have a good one near by.
Thanks for the advice