Fault Phenomenon: LiuGong HBT120A lubrication functions normally when cold. When pumping high-grade concrete (operating temperature), the lubrication system clogs, the distributor does not actuate, and eventually wear occurs.

Troubleshooting Process:
– Checked lubricating grease: grade correct, no impurities.
– Checked lubrication pump: pumping pressure normal, no leaks.
– Checked distributor: distributor piston moves freely, no sticking.
– Measured lubrication system pressure at operating temperature: found pressure too high.

Root Cause: The internal check valve in the lubrication distributor sticks due to heat, preventing it from unloading.

Required Parts: Lubrication distributor assembly.