Fault Phenomenon: Caterpillar 140M grader a loud impact sound occurs when the blade reaches the limit during side shift.

Troubleshooting Process:
– Checked cushion valve: spool stuck.
– Checked cylinder: internal cushion structure worn.
– Checked accumulator: system accumulator pressure low.
– Checked fluid: fluid viscosity too low.

Root Cause: The internal cushion valve in the blade side shift cylinder failed, unable to absorb kinetic energy.

Required Parts: Blade side shift cylinder repair kit.