Fault Phenomenon: Caterpillar 140M grader blade side shift cylinder external leak, piston rod surface has deep grooves.

Troubleshooting Process:
– Checked oil seal: seal lip cut by hard particles.
– Checked environment: mineral powder or sand entering wiper seal.
– Checked lubrication: lack of grease protection.
– Checked operation: side shift impact against obstacles.

Root Cause: A damaged wiper seal allowed hard particles to enter, scoring the piston rod during reciprocation and subsequently damaging the oil seal.

Required Parts: Replace piston rod (or re-chrome) and oil seal repair kit.