XCMG QY25K5 Luffing Cylinder Seal Kit
The luffing cylinder controls boom angle under heavy load. A successful reseal depends on surface condition and the exact cylinder—not a generic bag of O-rings.
The Match That Matters
Confirm whether leakage is external or the boom is drifting internally, then send the cylinder label.
What the Symptom Really Tells You
Boom lowering can come from piston bypass or the holding valve. A scored rod will damage a new rod seal quickly.
Workshop Notes
Support the boom mechanically, rebuild cleanly, protect seal lips and conduct controlled pressure, leakage and holding tests.
XCMG Balance Valve 803001825 · XCMG QY50K Hydraulic Pump 803000260
Buyer FAQ
Will seals stop boom drift?
Only if cylinder bypass is confirmed.
Why inspect the rod?
Surface damage causes repeat leaks.
What else should be checked?
Guides, wiper and holding valve.
Packing: Seal groups are labelled by piston and gland position.
