Fault Phenomenon: Liebherr LTM1120 luffing cylinder piston rod has obvious hydraulic oil seepage, pressure cannot be maintained during operation.

Troubleshooting Process:
– Cleaned cylinder surface to confirm leak point: located at piston rod seal.
– Checked piston rod surface: found minor scoring.
– Disassembled cylinder to inspect seals: composite seal aged and cracked.

Root Cause: The luffing cylinder piston rod seal assembly aged and failed, combined with minor scoring on the piston rod.

Required Parts: Cylinder seal repair kit, polish piston rod or replace cylinder assembly.