Deere 4020 steering issue

[JasG]

We have an old (dash model) 4020 that the steering is acting up and I need to know what the probable cause is.

The issue is it seems to steer to the right fairly well. When turning to the left it acts like it's binding. The wheel stops and doesn't want to go any further. If you bring the steering wheel back to the right just a little, it will then allow you to turn further left. It probably stops 4 times going from a full right turn to a full left turn. I noticed also today that when not moving forward or back and turning the wheel. When it stops the tires are "pulsing" like the tie rod is bouncing back and forth. The pulsing seems to be greater that the amount of movement I see from the tie rod. So some of that might be the whole front axle is pulsing.

Would this issue be the steering valve assembly the steering wheel is attached to of the front steering cylinder?

 

[jd110]

Are the other hydraulics working normally and smoothly? Do you have 2300 psi pressure? If so, then yes I would say your problem is in steering valve. If not, then hydraulics need to be working properly before deciding steering valve is bad.

 

[JasG]

Yes the other hydraulics seem to be fine.

Thank you for the information.

 

[blksmoke]

Air is in the steering circuit of the hydraulics.. raise front wheels off the ground, see if tractor steers correctly. Most likely will need to overhaul steering vavle..