Imagine this: A 2023 LiuGong 856H loader is hard at work in a construction yard, tasked with stacking gravel. Suddenly, its boom cylinder(model CBGJ3160) starts acting up. The operator pushes the lever, but the boom rises slower than molasses, struggling even with half a load. By noon, it can barely lift a third of its rated capacity. Meanwhile, the bucket cylinder (model CDB250) on a nearby XCMG LW500FN is causing trouble too—when the operator tries to dump a load, the bucket creaks and stalls mid-tilt, as if fighting against an invisible force. These aren’t just minor glitches; they’re cries for help from the hydraulic heart of the machines.
Solution:
The Numbers Behind the Struggle
• Boom Cylinder (CBGJ3160): Designed for a maximum working pressure of 25 MPa, this cylinder in the LiuGong 856H relies on a 125mm piston diameter and 70mm rod diameter to generate 300 kN of lifting force. When internal leakage occurs due to worn U-cup seals, pressure drops by 30-40%, slashing lifting power.
• Bucket Cylinder (CDB250): In the XCMG LW500FN, this cylinder operates at 22 MPa with a 100mm piston. A clogged return line (common with 500+ hours of use) creates 5-7 MPa of backpressure, making tilting feel labored and slow.
Fixing the Lift
• For the CBGJ3160 boom cylinder: Replace NBR rubber piston seals with polyurethane alternatives (better for high temps). Hone the 缸筒 (cylinder barrel) if scratches deeper than 0.2mm are found, then flush the system with hydraulic oil to remove debris.
• For the CDB250 bucket cylinder: Inspect the return hose for kinks or blockages—replace if bulging. Clean the inline filter (mesh size 25μm) and adjust the relief valve to restore pressure to 22 MPa. Test by tilting a full bucket; it should complete the motion in 3-4 seconds.
