The 804000053 Cycloidal Motor (also known as orbital hydraulic motor, low speed high torque hydraulic motor, cycloidal pinwheel motor, hydraulic orbit motor, LSHT motor, orbital gear motor, hydraulic rotary actuator, and hydromotor) is a genuine OEM high-torque hydraulic component manufactured by XCMG for motor graders and heavy construction equipment. This precision-engineered cycloidal motor converts hydraulic flow into smooth rotational power for blade circle rotation, steering systems, and auxiliary drives on XCMG GR series motor graders.
Designed to operate within XCMG’s working hydraulic pressure of 16 MPa (2,320 psi) and featuring high volumetric efficiency, the 804000053 cycloidal motor delivers consistent low-speed, high-torque output essential for precise blade positioning and circle rotation. It directly replaces worn, leaking, or seized orbital motors on XCMG GR135, GR165, GR180, GR215, GR260, GR300, and GR350 motor graders.
Each unit features a robust gerotor gear set, high-strength cast iron housing, and precision-ground internal components. The cycloidal motor provides smooth, jerk-free rotation even at low speeds, enabling operators to make fine adjustments to blade angle and circle position during precision grading operations.
| Parameter | Specification |
|---|---|
| OEM Number | 804000053 |
| Brand | XCMG (Genuine Original Equipment) |
| Product Type | Cycloidal Hydraulic Motor / Orbital Motor (Low Speed High Torque) |
| Displacement | 195 cc/rev to 375 cc/rev (depending on application configuration) |
| Maximum Operating Pressure | 16 MPa (160 bar / 2,320 psi) continuous – 18 MPa (180 bar / 2,610 psi) intermittent |
| Proof Pressure | 24 MPa (240 bar / 3,480 psi) |
| Maximum Differential Pressure | 200 bar (2,900 psi) |
| Nominal Torque (at rated pressure) | 450 – 650 Nm (depending on displacement) |
| Speed Range | 0 – 500 rpm (continuous), 0 – 600 rpm (intermittent) |
| Minimum Starting Torque | ≥ 85% of nominal torque |
| Volumetric Efficiency | ≥ 92% at rated pressure |
| Hydraulic Fluid | ISO VG 46 or VG 68 (mineral oil-based) |
| Fluid Temperature Range | -20°C to +80°C (-4°F to +176°F) |
| Viscosity Range | 15 – 400 cSt |
| Housing Material | High-strength cast iron (GGG-50 / ductile iron) |
| Shaft Type | Splined shaft (standard XCMG interface) |
| Mounting Flange | SAE A 2-Bolt or 4-Bolt (depending on configuration) |
| Port Threads | BSPP (G-thread) / SAE O-ring ports |
| Weight | Approximately 10.2 kg (22.5 lbs) |
| Corrosion Protection | Epoxy primer + polyurethane topcoat (500h salt spray resistance) |
| Compatible Models | XCMG GR135, GR165, GR180, GR215, GR260, GR300, GR350, GR2403 motor graders |
| Certifications | ISO 9001:2015, ISO 14001, CE, RoHS |
The XCMG 804000053 Cycloidal Motor is the power source for the blade circle rotation system on GR series motor graders. Mounted directly to the worm gear housing, this orbital motor receives pressurized hydraulic oil from the load‑sensing control valve and converts it into smooth rotational motion. The 360-degree continuous rotation capability allows operators to position the blade at any angle relative to the machine centerline, essential for ditching, slope work, and shoulder grading.
Unlike traditional gear motors, the cycloidal design uses an internal gerotor gear set that provides exceptionally high starting torque—over 85% of the motor’s nominal torque rating. This means the 804000053 can break the circle loose from packed dirt or frozen ground without stalling, even at low engine RPM. The low-speed, high-torque (LSHT) characteristic is what makes cycloidal motors the preferred choice for grader circle drive applications.
The motor’s compact axial design allows it to fit within the tight confines of the grader’s circle drive housing. The splined output shaft directly engages the worm gear input, eliminating the need for additional couplings or adapters. When the original motor fails—exhibiting symptoms such as erratic rotation, complete loss of circle turn, or external oil leakage—replacing it with a genuine XCMG 804000053 restores full circle rotation capability.
The 804000053 cycloidal motor operates on an eccentric motion principle. Inside the motor housing, a lobed stator ring and a mating rotor (gerotor) create expanding and contracting chambers as the rotor orbits around the stator. High-pressure hydraulic oil enters the chambers, forcing the rotor to rotate and transmitting torque to the output shaft. This design eliminates the need for complex valve timing mechanisms, resulting in a simple, robust, and highly reliable motor with few moving parts.
The motor’s volumetric efficiency—the ratio of actual output flow to theoretical flow—exceeds 92% at rated pressure, ensuring minimal internal leakage and consistent performance even after thousands of operating hours. The internal clearances are optimized for ISO VG 46 hydraulic oil at operating temperatures between -20°C and +80°C. For extreme cold environments, a lower viscosity oil may be specified, but the 804000053 is designed to perform reliably across a wide range of conditions.
XCMG’s cycloidal motors feature an advanced end-face compensation system that maintains high volumetric efficiency even as internal components wear. This self-compensating design extends the service life of the motor and maintains consistent circle rotation speed throughout the motor’s operational life.
The 804000053 cycloidal motor is designed to operate within XCMG’s advanced load-sensing hydraulic architecture, which uses a variable-displacement piston pump to deliver only the flow required by the active functions. The working hydraulic pressure across the XCMG GR series ranges from 16 MPa (2,320 psi) on models like the GR135, GR165, and GR215, up to 22 MPa (3,190 psi) on larger models such as the GR500.[reference:0][reference:1] The 804000053 is rated for continuous operation at 16 MPa and intermittent operation up to 18 MPa, making it suitable for all GR series applications.
The motor’s speed range—0 to 500 rpm continuous, 0 to 600 rpm intermittent—provides operators with precise control over circle rotation speed. At low flow rates, the motor rotates slowly and smoothly, allowing fine adjustments to blade angle during finish grading. At higher flow rates, the motor can rapidly reposition the circle when moving between passes, improving overall cycle times.
XCMG has engineered the 804000053 to be fully compatible with the GR series’ electro-hydraulic control system. When the operator moves the circle rotation lever, a proportional solenoid valve meters oil to the motor, providing infinitely variable speed control. The motor’s low starting torque requirement (only 15% of nominal torque) ensures immediate response even from a dead stop, eliminating the lag common with older gear-type motors.
Each 804000053 cycloidal motor is manufactured in XCMG’s ISO 9001:2015-certified hydraulic facility. The gerotor gear set is produced from case-hardened steel, then ground and honed to achieve a surface finish of Ra ≤ 0.4 µm, ensuring minimal friction and long wear life. The housing is cast from high-grade ductile iron (GGG-50), then machined on CNC equipment to exact tolerances. The output shaft is splined to XCMG’s proprietary specification, ensuring positive engagement with the circle drive worm gear.
After assembly, each motor is tested on a dynamometer to verify torque output, speed range, volumetric efficiency, and case drain leakage. The motor is run at 150% of rated pressure (24 MPa / 3,480 psi) for five minutes to confirm structural integrity. Only motors that pass all tests are approved for sale as genuine XCMG components.
The exterior finish consists of an epoxy primer followed by a polyurethane topcoat, providing over 500 hours of salt spray resistance per ASTM B117. This corrosion protection is essential for graders operating in coastal environments, winter road salt applications, or high-humidity conditions.
Replacing a failed cycloidal motor is a straightforward procedure for a qualified technician. Begin by parking the grader on level ground, lowering the blade to the ground, and shutting off the engine. Relieve hydraulic pressure by cycling all control levers with the engine off. Disconnect the hydraulic hoses from the motor ports, capping them immediately to prevent contamination. Remove the mounting bolts securing the motor to the worm gear housing. Carefully extract the motor, noting the orientation of the splined shaft.
Clean the mounting surface on the worm gear housing and inspect the splined input shaft for wear or damage. Install the new 804000053 motor, ensuring the splines align properly. Apply a small amount of clean hydraulic oil to the O-rings on the hose fittings before reconnecting. Torque the mounting bolts to the specification in the service manual (typically 50-60 Nm). Reconnect the hoses, being careful not to cross-thread the fittings.
After installation, start the engine and cycle the circle rotation control in both directions to purge air from the motor. Check for external leaks at all connections. Run the grader through several full circle rotations in both directions, listening for any unusual noise. If the circle rotates smoothly and holds position when the control is released, the installation is successful.
Aftermarket orbital motors often use lower-grade gerotor materials that wear rapidly, leading to internal leakage and loss of circle rotation power. The genuine XCMG 804000053 is manufactured from case-hardened steel and precision-ground to original equipment tolerances, providing consistent torque output over thousands of operating hours. Aftermarket motors may also have incorrect shaft spline dimensions, leading to premature failure of the worm gear input.
Counterfeit cycloidal motors often omit the critical end-face compensation feature, resulting in a motor that works well when new but loses efficiency rapidly as internal components wear. The 804000053 includes XCMG’s proprietary wear compensation system, maintaining high volumetric efficiency throughout the motor’s service life. Additionally, genuine XCMG motors are serialized and traceable, whereas counterfeit products carry no warranty or quality guarantee.
XCMG provides a 12-month warranty against manufacturing defects. Each motor is stamped with the XCMG logo and part number. This supersedes older numbers 803010966 and 803010967, with improved seal materials and a more robust splined shaft design.
Common symptoms of a failing cycloidal motor include: erratic circle rotation (jerky or surging motion), complete loss of circle turn in one or both directions, excessive case drain flow (indicating internal leakage), external oil leakage from the shaft seal or housing joints, and unusual noise (grinding or whining) during operation. Also, if the circle rotates slowly or stalls under light load, the motor’s internal components may be worn.
Preventive replacement is recommended every 6,000 operating hours or whenever the motor shows signs of wear. The cost of a genuine 804000053 cycloidal motor is minimal compared to the cost of downtime caused by a failed circle drive system. A grader that cannot rotate its blade is unable to perform ditching, slope work, or shoulder grading—operations that represent a significant portion of motor grader utilization.
During routine maintenance, check the case drain line for excessive flow. A simple test: with the motor operating at rated pressure, measure the oil flow from the case drain port. If flow exceeds 10% of the inlet flow, internal wear is excessive and replacement should be scheduled. Also, inspect the motor mounting bolts for tightness and the shaft seal for oil leakage.
The 804000053 Cycloidal Motor is stocked in XCMG regional warehouses in North America (Houston), Europe (Rotterdam), Middle East (Dubai), and Asia (Shanghai). Standard air freight delivers within 3-7 business days worldwide. Expedited shipping (1-2 days) is available for urgent breakdowns.
Bulk orders (5+ units) receive volume discounts and can be shipped via sea freight. Each motor is individually packed in a foam-lined carton with desiccant and anti-static protection. For large fleets, consignment stock programs are available to ensure immediate availability and reduced downtime.
Don’t let a failed cycloidal motor leave your grader unable to rotate the blade. Order the genuine XCMG 804000053 Cycloidal Motor today and restore full circle rotation capability to your motor grader.
The 804000053 Cycloidal Motor is a critical component in your motor grader’s blade circle drive system. A failed motor prevents the operator from rotating the blade, severely limiting the machine’s versatility and productivity. Keep a spare motor in your parts inventory for rapid field replacement, and always replace with genuine XCMG components.
Upgrade your motor grader’s circle rotation reliability with the XCMG genuine cycloidal motor. Engineered for strength, smooth operation, and durability – order now and experience the quality that keeps your grader productive.
