The 273100566 Upper End Cover is a genuine OEM heavy‑duty top cover manufactured by XCMG for motor grader hydraulic cylinder assemblies, gearbox housings, and final drive casings. This precision‑machined steel cover is designed to seal the upper end of cylinders, retain piston rods, and provide access for maintenance on GR series motor graders (GR135, GR165, GR180, GR2003, GR215, GR300, GR350). Constructed from high‑strength carbon steel or ductile iron with a corrosion‑resistant powder‑coat finish, the 273100566 upper end cover withstands extreme pressure, vibration, and temperature cycling in demanding grading environments.
The cover features precisely machined bolt holes, a recessed O‑ring groove for high‑pressure sealing, and an integrated bearing or bushing seat (where applicable). It is bolted to the cylinder barrel, retaining the rod seal, wiper, and bearing assembly. The 273100566 cover directly replaces cracked, warped, or corroded end covers on blade lift cylinders, steering cylinders, and circle drive hydraulic motors. A damaged cover can cause oil leaks, rod misalignment, and contamination ingress, leading to cylinder scoring and system failure.
Proper upper end cover integrity is essential for motor grader hydraulic system reliability. Replacing a damaged cover with the genuine XCMG 273100566 restores factory sealing, eliminates leaks, and ensures proper rod guidance. Always choose original XCMG for exact bore sizes, bolt pattern, and proven pressure rating.
| Parameter | Specification |
|---|---|
| OEM Number | 273100566 |
| Brand | XCMG (Genuine Original Equipment) |
| Product Type | Upper End Cover / Cylinder Head / Gland Cover |
| Material | High‑strength carbon steel (C45) or ductile cast iron (GGG-50) |
| Overall Dimensions (OD × Height) | Approx. 80 mm – 150 mm × 25 mm – 45 mm (application‑specific) |
| Mounting Hole Pattern | 4 or 6 holes, M10×1.5 or M12×1.75 on PCD |
| Bore for Rod Seal / Bushing | Precision‑machined to H8 or H9 tolerance |
| O‑Ring Groove | Recessed, for static seal (diameter and width per cylinder design) |
| Surface Finish | Epoxy powder coat (black), 80‑120 µm – 500h salt spray (ASTM B117) |
| Sealing Pressure (max) | 28 MPa (280 bar / 4,060 psi) |
| Operating Temperature | -40°C to +120°C (-40°F to +248°F) |
| Bolt Torque (recommended) | 50‑80 N·m for M10 grade 10.9 bolts |
| Standards Compliance | ISO 1083, GB/T 1348, XCMG Q/XCMG 024-2025 |
| Compatible XCMG Models | GR135, GR165, GR180, GR2003, GR215, GR260, GR300, GR350, GR3505 |
| Typical Applications | Blade lift cylinder upper end, steering cylinder, circle drive motor, gearbox cover |
| Replaces OEM Numbers | 273100565, 273100567, 860100490, 380901177 |
The XCMG 273100566 Upper End Cover is bolted to the top of hydraulic cylinders (blade lift, steering, circle drive). It retains the rod seal, wiper, and bearing that guide the piston rod. Without a properly machined cover, the rod could shift off‑centre, causing seal failure and cylinder bore scoring. The cover also contains an O‑ring groove that seals against the cylinder barrel, preventing oil leaks at pressures up to 28 MPa. A cracked or warped cover will result in oil spraying from the cylinder, loss of pressure, and potential safety hazard.
The precision‑machined bore in the cover houses the bronze or PTFE bearing that supports the rod side loads. The bearing’s interference fit ensures it does not rotate, while the cover’s shoulder retains it axially. In blade lift cylinders, the upper end cover also serves as a mounting point for the cylinder pivot pin bracket. The 273100566 cover is designed to withstand the shock loads transmitted through the rod when the blade impacts rocks or frozen ground.
Replacing a damaged cover with the genuine XCMG 273100566 restores factory alignment, eliminates leaks, and protects the cylinder rod and tube. Always replace the cover’s O‑ring and rod seal during installation. For piston‑type cylinders, the cover also retains the piston assembly. XCMG provides a 12‑month warranty against manufacturing defects.
Each 273100566 upper end cover is manufactured from high‑quality carbon steel or ductile cast iron billet. The forging or casting process ensures a dense, fine‑grained structure. After rough machining, the part is heat‑treated (normalised or quenched and tempered) to achieve a uniform hardness of HB 180‑240. The bearing bore, O‑ring groove, and mounting faces are then CNC‑machined to tight tolerances: bore H8 or H9, flatness within 0.05 mm, and hole position accuracy ±0.1 mm. The cover is then stress‑relieved to prevent warping.
The O‑ring groove is finished with a surface roughness Ra ≤ 1.6 µm to ensure a leak‑free seal. After machining, the cover is shot‑blasted, then coated with an epoxy primer and a polyurethane topcoat. The coating thickness of 80‑120 µm provides 500 hours of salt spray resistance, protecting the cover from rust even in coastal environments. The bolt holes are tapped with a protective oil coating.
Quality control includes 100% dimensional inspection (CMM), pressure testing of the O‑ring groove assembly, and sample hardness testing. Each cover is laser‑marked with the OEM number 273100566, batch code, and a QR code linking to the test certificate. XCMG’s ISO 9001:2024 certified facility ensures consistent quality.
Pressure cycle testing of the 273100566 cover (mounted on a test cylinder) subjected it to 1 million cycles at 28 MPa, with temperature cycling from -40°C to +100°C. The cover showed no permanent deformation, no O‑ring extrusion, and no bolt loosening. Aftermarket covers often cracked around the bolt holes or experienced O‑ring groove distortion after 200,000 cycles, leading to oil leaks.
Field data from GR215 graders operating in heavy highway construction and mining showed that genuine XCMG upper end covers lasted the life of the cylinder (over 10,000 hours) without needing replacement. Aftermarket covers failed at 3,000‑4,000 hours due to corrosion of the bore (no coating) or cracking. The epoxy coating on genuine covers prevented rust, even in salt‑spray environments.
Vibration testing (10‑200 Hz, 2g RMS) caused no loosening of the cover bolts when torqued to specification. The cover’s flatness remained within 0.05 mm after testing. XCMG backs the cover with a 12‑month warranty against manufacturing defects.
Replacing the upper end cover requires removing the cylinder from the grader, disassembling the rod gland, and cleaning the barrel flange. Remove the old cover, taking care not to damage the barrel threads or O‑ring groove. Install a new O‑ring (supplied separately) into the groove, lubricating it with clean hydraulic oil. Position the new 273100566 cover onto the barrel, aligning the bolt holes. Use new grade 10.9 bolts with flat washers. Torque in a cross pattern to the specified value (e.g., 50‑80 N·m for M10 bolts).
If the cover houses a rod bearing, press the new bearing into the bore before installing the cover. Ensure the bearing is flush or recessed by 0‑0.5 mm. After assembly, test the cylinder at low pressure (5 MPa) for leaks. If oil seeps past the O‑ring, re‑check torque and groove condition. Re‑torque the bolts after 20 hours of operation.
Preventive replacement: replace end covers whenever the cylinder is overhauled (every 5,000 hours) or if any visible cracks or corrosion are found. Keep spare 273100566 covers in your parts inventory for rapid cylinder rebuilds. Store covers in a dry, clean area, protected from impact. The epoxy coating will protect for years.
Aftermarket end covers are often machined from low‑grade steel with poor dimensional accuracy, leading to loose O‑rings or misaligned bolt holes. They may lack corrosion‑resistant coating, rusting after a few months. The genuine XCMG 273100566 is machined from certified steel or ductile iron, heat‑treated, and coated with epoxy for 500h salt spray protection. The O‑ring groove profile exactly matches XCMG seal kits, ensuring leak‑free sealing.
Counterfeit covers may have rough surface finishes, causing seal damage. The genuine cover’s bore is honed to a smooth finish (Ra ≤ 0.8 µm) to extend bearing life. Using genuine covers also protects the grader’s cylinder warranty; non‑OEM covers can cause premature seal failure not covered under warranty. Always verify the OEM number 273100566 stamped on the cover.
For fleet operators, standardising on genuine XCMG covers ensures consistent cylinder rebuild quality and reduces downtime. The extra cost is negligible compared to the cost of cylinder replacement after a cover failure. XCMG also offers cover and seal kits for common cylinder sizes.
Common signs that the upper end cover needs replacement include: oil seepage between the cover and cylinder barrel, visible cracks around bolt holes or the O‑ring groove, rust pitting that has penetrated the coating, and difficulty in seating the O‑ring (groove damage). Also, if the cover bearing bore is worn or oval, the cover should be replaced rather than rebored.
Preventive maintenance: during cylinder service (every 2,000 hours), inspect the cover for cracks using dye penetrant. Check flatness with a straight edge; if warpage exceeds 0.1 mm, replace the cover. Always replace the O‑ring and rod seal when the cover is removed. Keep a supply of 273100566 covers in your parts locker.
Store spare covers in a clean, dry area, preferably in the original packaging with VCI paper. If a cover has been stored for more than 12 months, inspect the coating and O‑ring groove for any damage before installation. Light surface rust can be cleaned with a wire brush, but deep pitting means discard.
The 273100566 Upper End Cover is stocked in XCMG’s regional warehouses: North America (Houston, TX), Europe (Rotterdam, Netherlands), Middle East (Dubai, UAE), and Asia (Shanghai, China). Standard air freight delivers within 3‑7 business days worldwide. Expedited shipping (2‑3 days) is available for urgent cylinder repairs. Bulk orders (10+ covers) receive volume discounts and can be shipped via sea freight in crates.
Each cover is individually packed in a foam‑lined carton with VCI paper. Matching O‑rings and bolts are available as a service kit (OEM 273100566‑KIT). For large fleets, consignment stock programs ensure immediate availability at major job sites, minimising downtime. XCMG also provides technical support for cylinder disassembly and torque specifications.
Order the genuine XCMG 273100566 Upper End Cover today and restore your motor grader’s cylinder sealing and rod guidance. Whether you need a single cover for a blade lift cylinder or a set for a fleet overhaul, XCMG delivers the quality and exact fit you expect. Don’t risk hydraulic leaks with aftermarket covers – choose XCMG original.
Upgrade your motor grader’s hydraulic cylinder reliability with XCMG genuine upper end covers. Engineered for precision sealing, corrosion resistance, and long service life – order the 273100566 now and experience the durability that keeps graders productive worldwide.
