Fault Phenomenon: Lonking 855 wheel loader a metallic impact sound occurs when the boom reaches the top of its lift.

Troubleshooting Process:
– Disassemble cylinder: internal cushion polyurethane pad shattered.
– Checked operation: frequently moving boom to limit quickly.
– Checked oil temperature: high temperature accelerated rubber aging.
– Checked piston: piston hitting cylinder bottom.

Root Cause: The cushion pad inside the boom lift cylinder shattered due to long-term impact and high-temperature aging, losing its cushioning effect.

Required Parts: Boom lift cylinder seal and cushion pad repair kit.