Product Overview
The MS18-8-111-F12-2A50-0000 is a dual-displacement radial piston hydraulic motor from Poclain Hydraulics’ MS/MSE18 series, featuring a full displacement of 1395 ml/r and a half displacement of 698 ml/r. The MS/MSE18 series is the large frame offering in Poclain’s multi-purpose motor line, covering displacements from 1091 to 2812 cc/rev with up to 70 kW (94 HP) power, 17,900 N·m (13,202 lb-ft) maximum torque and 450 bar (6,527 psi) maximum pressure, with a multi-speed concept reaching up to 170 rpm.
The MS/MSE18 series employs a modular design concept allowing a single base motor to be configured with different displacement groups, flow-distribution modules, brake modules and output-end modules, serving construction equipment, material handling, agriculture, environment, mining, rail, marine and industry. The series is built on a tried and tested radial piston cam design, featuring low noise, high radial load capacity and high starting torque, with hydrostatic dynamic braking as an inherent design feature. The MS18/MSE18 motor’s starting performance is 15% greater than a high-speed motor and gearbox combination and 12% higher overall.
The model code breaks down as follows: MS18 identifies the MS series 18 frame size; 8 denotes displacement group 8 (1395/698 ml/r dual displacement); 111 is the flow-distribution/function module code; F12 is the shaft and mounting configuration code; 2A50 is the wheel flange mounting and output-end code; 0000 is the standard option combination.
Every MS18-8-111-F12-2A50-0000 unit undergoes 100% simulated operating-condition bench testing prior to shipment, covering pressure cycling, speed shifting and thermal variation. Mounting flange, shaft end and port dimensions match the original Poclain MS18 series exactly, enabling true drop-in interchangeability with zero modification required.
Technical Specifications
MS18/MSE18 Series Frame Size Specifications:
MS18-6: Full displacement 1091 ml/r (66.5 cu.in/rev), half displacement 546 ml/r (33.3 cu.in/rev), theoretical torque at 10 MPa 1,735 N·m (1,280 lb-ft), rated speed 55 rpm, speed range 0–150 rpm
MS18-8 (This Model): Full displacement 1395 ml/r (85.1 cu.in/rev), half displacement 698 ml/r (42.5 cu.in/rev), theoretical torque at 10 MPa 2,218 N·m (1,636 lb-ft), rated torque 5,212 N·m, rated pressure 25 MPa, max pressure 40 MPa, max power 62 kW, rated speed 55 rpm, speed range 0–150 rpm
MS18-9: Full displacement 1571 ml/r (95.8 cu.in/rev), half displacement 785 ml/r (47.9 cu.in/rev), theoretical torque at 10 MPa 2,498 N·m, rated torque 5,870 N·m, rated pressure 25 MPa, max pressure 40 MPa, max power 62 kW, rated speed 55 rpm, speed range 0–150 rpm
MS18-0: Full displacement 1747 ml/r (106.5 cu.in/rev), half displacement 873 ml/r (53.3 cu.in/rev), theoretical torque at 10 MPa 2,778 N·m, rated torque 6,528 N·m, rated pressure 25 MPa, max pressure 40 MPa, max power 62 kW, rated speed 55 rpm, speed range 0–150 rpm
MS18-1: Full displacement 1911 ml/r (116.6 cu.in/rev), half displacement 955 ml/r (58.3 cu.in/rev), theoretical torque at 10 MPa 3,038 N·m, rated torque 7,140 N·m, rated pressure 25 MPa, max pressure 35 MPa, rated speed 55 rpm, speed range 0–135 rpm
MS18-2: Full displacement 2099 ml/r (128.0 cu.in/rev), half displacement 1049 ml/r (64.0 cu.in/rev), theoretical torque at 10 MPa 3,337 N·m, rated torque 7,843 N·m, rated pressure 25 MPa, max pressure 35 MPa, rated speed 50 rpm, speed range 0–125 rpm
MSE18-0: Full displacement 2340 ml/r (142.7 cu.in/rev), half displacement 1170 ml/r (71.4 cu.in/rev), theoretical torque at 10 MPa 3,721 N·m, rated pressure 25 MPa, max pressure 400 bar
MSE18-1: Full displacement 2560 ml/r (156.1 cu.in/rev), half displacement 1280 ml/r (78.1 cu.in/rev), theoretical torque at 10 MPa 4,070 N·m, rated pressure 25 MPa, max pressure 400 bar
MSE18-2: Full displacement 2812 ml/r (171.5 cu.in/rev), half displacement 1406 ml/r (85.8 cu.in/rev), theoretical torque at 10 MPa 4,471 N·m, rated pressure 25 MPa, max pressure 400 bar
MS18/MSE18 Series Common Specifications:
Series Max Displacement: 2,812 cc/rev (171.6 cu.in/rev)
Series Max Torque: 17,900 N·m (13,202 lb-ft)
Series Max Pressure: 450 bar (6,527 psi)
Series Max Power: 70 kW (94 HP)
Series Max Speed: 170 rpm
Type: Radial piston LSHT hydraulic motor (internal curve cam ring design)
Control: Single or dual displacement (1C/2C)
Brake: Service brake, parking brake and hydrostatic boosted brake options
Motor Type: Wheel motor / shaft motor (modular)
Anti-Skid Option: TwinLock™ integrated anti-skid available
Motor Inertia: 0.2 kg·m²
Displacement Range: 1091–2812 cc/rev
Original Design: Poclain Hydraulics, France
MS18-8-111-F12-2A50-0000 Additional Specifications:
Model Code: MS18-8-111-F12-2A50-0000
Type: Radial piston LSHT hydraulic motor, internal curve cam ring design
Displacement: 1395 ml/r (85.1 cu.in/rev) full / 698 ml/r (42.5 cu.in/rev) half
Displacement Ratio: 2:1
Theoretical Torque at 10 MPa: 2,218 N·m (1,636 lb-ft)
Rated Torque: 5,212 N·m (3,844 lb-ft)
Rated Working Pressure: 25 MPa (250 bar)
Max Working Pressure: 40 MPa (400 bar)
Max Power: 62 kW (83 HP)
Rated Speed: 55 rpm
Speed Range: 0–150 rpm
Valving Type: No. 1 valving module (111 code)
Mounting Flange: Wheel flange mounting (2A50 configuration)
Port Connections: ISO 6162 flanges & ISO 9974-1 connections
Anti-Skid Option: TwinLock™ available
Motor Type: Wheel motor
Operating Temperature Range: -40°C to +115°C
Hydraulic Fluid: Mineral oil (ISO VG46/68), synthetic oil, water glycol
Original Design: Poclain Hydraulics, France
Key Technical Advantages
1. Internal Curve Radial Piston Design for High Startup Torque and Smooth Low-Speed Operation
The MS18-8-111 employs Poclain’s patented internal curve radial piston design, with multiple pistons arranged radially around a cam ring to deliver high torque at extremely low speeds. With theoretical torque of 2,218 N·m at 10 MPa and rated torque of 5,212 N·m at full displacement, the motor operates smoothly across the 0–150 rpm speed range without stick-slip. The MS18/MSE18 motor’s starting performance is 15% greater than a high-speed motor and gearbox combination and 12% higher overall.
2. Dual Displacement Design for Wide Operating Range
The MS18-8 features a dual-displacement cam ring design with on-line switching between 1395 ml/r full displacement and 698 ml/r half displacement for a 2:1 ratio. The full-displacement mode delivers maximum torque for heavy-duty startup and grade climbing; the half-displacement mode significantly increases speed capability for light-load cruising. A single motor covers the full spectrum from low-speed high-torque to high-speed low-torque operation.
3. Modular Architecture for Maximum Adaptability
The MS/MSE18 series employs Poclain’s modular design concept, allowing displacement group, flow-distribution module, brake module and output-end module to be reconfigured, with the modular design easing use on all demanding applications for the most demandable market as construction equipment, material handling, agricultural, environment, mining, on rail, marine and industry. The wheel flange mounting configuration (2A50) supports wheel-drive mounting for road rollers, wheel loaders, scrapers and mining equipment. Optional TwinLock™ integrated anti-skid provides differential locking via hydraulic control for improved traction. Brake options include service brake, parking brake and hydrostatic boosted brake modules.
4. High-Precision Cam Ring and High Radial Load Capacity
The MS18-8-111 cam ring is manufactured from high-hardness alloy steel with precision grinding to resist high-frequency contact fatigue from piston rollers. A hydrodynamic oil film forms between rollers and cam ring, significantly reducing wear rate and extending overhaul intervals. The motor can withstand substantial axial and radial forces, with large diameter bearing support enabling direct handling of wheel or tool-end radial loads without additional bearing support mechanisms. The modular design allows replacement of individual worn modules rather than the entire motor.
5. 100% Simulated Load Testing & Drop-In Interchangeability
Each MS18-8-111-F12-2A50-0000 unit is bench-tested under simulated operating conditions prior to dispatch, covering pressure cycling, speed shifting and thermal variation. Mounting flange, shaft end and port dimensions match the original Poclain MS18 series exactly, enabling direct replacement without pipework or interface modification. Both complete motors and spare parts are 100% interchangeable.
Application Areas
The MS18/MSE18 series is widely deployed in heavy-duty travel and tool drives:
Road Rollers: Bomag, HAMM and similar vibratory roller wheel drives and vibration shaft drives
Construction: wheel loaders (Caterpillar 938K/950GC, Volvo L110F/L120H, Komatsu WA320/WA380, JCB 436/456, Case 721G/821G)
Self-Propelled Sprayers: John Deere 4830/4930, Case IH Patriot 4430/4440, New Holland Guardian SP370F, Fendt Rogator 900, Amazone Pantera 7004, Agrifac Condor Endurance, Hardi Alpha 4100
Agriculture: combine harvesters (Claas Lexion 770/780)
Mining: roadheader star wheel drives, subsurface loaders, mining truck auxiliary drives
Marine & Offshore: deck machinery, winch drives
Industrial: shredders, industrial conveyors, mill drives
Expert Maintenance Tips
1. Dual Displacement Valving Module Maintenance: The dual displacement valving module is controlled by pilot pressure. If shift response is sluggish or excessively harsh, inspect the pilot control spool for sticking and the flow-distribution shaft O-rings for aging. Shift operations should be performed at low speed or standstill to avoid impact loading on the distribution mechanism. Inspect pilot control pressure and valving module seal condition every 1,000 hours.
2. Wheel Flange Mounting Surface Inspection: The MS18-8-111-F12-2A50 features wheel flange mounting. Periodically inspect the output flange plane and wheel hub mating surface for wear or deformation. Ensure flange mating surface parallelism deviation does not exceed 0.05 mm during installation, and tighten bolts evenly in a diagonal sequence to Poclain technical manual torque values. Mounting surface flatness requirement is 0.2 mm with Ra 12.5 μm surface roughness.
3. Oil Cleanliness and Temperature Control: Maintain system oil cleanliness at ISO 4406 18/16/13 or better. HV46 hydraulic oil is recommended. Operating oil temperature should be kept below 80°C; elevated temperatures accelerate seal degradation. Replace hydraulic oil and filter after the first 500 hours, then follow a 2,000-hour or annual replacement cycle. Case drain temperature is affected by pressure and speed and is always higher than circuit temperature—system temperature must not exceed 115°C at any point.
4. Drain Line Management and Housing Priming: The drain port must return to the reservoir independently—housing back pressure must not exceed 2 bar. The drain line end must remain submerged to prevent air ingestion. Fill the housing with clean hydraulic oil before first startup. After extended shutdown, fill the housing again before restarting. Installation should be performed in the reverse order of removal operations, referring to the General Installation manual.
5. Periodic Piston Group and Cam Ring Inspection: As a radial piston motor, the MS18-8-111’s primary wear points are the piston rollers and cam ring contact surface. Inspect piston roller wear and cam ring working surface every 2,000 hours. Both displacement cam surfaces require inspection. Abnormal noise or efficiency loss requires immediate shutdown and service. Use Poclain original specification parts when replacing piston groups to ensure fit accuracy and assembly torque per technical manual requirements.
6. Modular Repair Strategy: The MS/MSE18 series modular design allows replacement of individual worn modules rather than the entire motor. Establish a modular spare parts inventory including flow-distribution module seals, piston groups and cam rings to minimize machine downtime. When replacing modules, follow Poclain official technical manual torque values and assembly sequences.
