Fault Phenomenon: John Deere 750K dozer excessive play in front wheel steering, unstable driving.

Troubleshooting Process:
– Checked kingpin: excessive clearance between kingpin and bushing.
– Checked bushing: bronze bushing severely worn.
– Checked lubrication: grease fittings clogged, no grease.
– Checked steering linkage: tie rod ends also worn.

Root Cause: The front axle kingpin bushings were dry-worn due to long-term lack of lubrication, causing excessive clearance and affecting steering precision.

Required Parts: Front axle kingpin and bushing assembly.