MS08-2-D21-F08-1720 Poclain Motor | 450 Bar 934cc

Product Overview

The MS08-2-D21-F08-1720-8EJA is a dual-displacement radial piston hydraulic motor from Poclain Hydraulics’ MS/MSE08 series, featuring a full displacement of 934 ml/r and a half displacement of 467 ml/r. The MS/MSE08 series is the mid-large frame offering in Poclain’s multi-purpose motor line, covering displacements from 467 to 1,248 cc/rev with up to 41 kW (55 HP) power, 7,945 N·m (5,859 lb-ft) maximum torque and 450 bar (MS version) / 400 bar (MSE version) maximum pressure, with a multi-speed concept reaching up to 450 rpm.

The MS/MSE08 series is built on a tried and tested radial piston cam design that is continually being improved, delivering high efficiency at any speed or operating pressure. MS Classic range motors have established themselves as a benchmark in the hydraulic motor market thanks to their compactness, optimized cost and power density. The motor features low noise, high radial load capacity and high starting torque, with hydrostatic dynamic braking as an inherent design feature.

The model code breaks down as follows: MS08 identifies the MS series 08 frame size; 2 denotes displacement group 2 (934/467 ml/r dual displacement); D21 is the flow-distribution/function module code (D=dual displacement valving, 2=valving type, 1=standard configuration); F08 is the shaft and mounting configuration code; 1720 is the mounting flange and output-end code; 8EJA denotes additional options including port orientation, shaft seal type and monitoring interface.

Every unit undergoes 100% simulated operating-condition bench testing prior to shipment. Mounting flange, shaft end and port dimensions match the original Poclain MS08 series exactly, enabling true drop-in interchangeability with zero modification required.

Technical Specifications

MS08/MSE08 Series Frame Size Specifications:

• MS08-8: Full displacement 627 ml/r, half displacement 313 ml/r, theoretical torque at 10 MPa 937 N·m, rated torque 2,343 N·m, max power 36 kW, rated pressure 25 MPa, max pressure 40 MPa, rated speed 70 rpm, speed range 0–170 rpm

• MS08-9: Full displacement 702 ml/r, half displacement 351 ml/r, theoretical torque at 10 MPa 1,049 N·m, rated torque 2,623 N·m, max power 36 kW, rated pressure 25 MPa, max pressure 40 MPa, rated speed 70 rpm, speed range 0–170 rpm

• MS08-0: Full displacement 780 ml/r, half displacement 390 ml/r, theoretical torque at 10 MPa 1,166 N·m, rated torque 2,914 N·m, max power 36 kW, rated pressure 25 MPa, max pressure 40 MPa, rated speed 70 rpm, speed range 0–170 rpm

• MS08-1: Full displacement 857 ml/r, half displacement 428 ml/r, theoretical torque at 10 MPa 1,281 N·m, rated torque 3,202 N·m, max power 36 kW, rated pressure 25 MPa, max pressure 35 MPa, rated speed 65 rpm, speed range 0–155 rpm

• MS08-2 (This Model): Full displacement 934 ml/r (57.0 cu.in/rev), half displacement 467 ml/r (28.5 cu.in/rev), theoretical torque at 10 MPa 1,396 N·m, rated torque 3,490 N·m, max power 36 kW, rated pressure 25 MPa, max pressure 35 MPa, rated speed 65 rpm, speed range 0–140 rpm

MS08/MSE08 Series Common Specifications:

• Series Max Displacement: 1,248 cc/rev (76.1 cu.in/rev)

• Series Max Torque: 7,945 N·m (5,859 lb-ft)

• MS Series Max Working Pressure: 450 bar (6,527 psi)

• MSE Series Max Working Pressure: 400 bar (5,802 psi)

• Series Max Power: 41 kW (55 HP)

• Series Max Speed: 450 rpm

• Type: Radial piston LSHT hydraulic motor (internal curve cam ring design)

• Control: Single or dual displacement

• Brake: Service brake, parking brake options

• Motor Type: Wheel motor / shaft motor (modular)

• Anti-Skid Option: TwinLock™ integrated anti-skid available

• Motor Inertia: 0.05 kg·m²

• Displacement Range: 467–1,248 cc/rev

• Original Design: Poclain Hydraulics, France

MS08-2-D21-F08-1720-8EJA Additional Specifications:

• Model Code: MS08-2-D21-F08-1720-8EJA

• Type: Radial piston LSHT hydraulic motor, internal curve cam ring design

• Displacement: 934 ml/r (57.0 cu.in/rev) full / 467 ml/r (28.5 cu.in/rev) half

• Displacement Ratio: 2:1

• Rated Working Pressure: 25 MPa (250 bar)

• Max Working Pressure: 35 MPa (350 bar) / 450 bar (MS version peak)

• Rated Torque: 3,490 N·m (2,574 lb-ft)

• Theoretical Torque at 10 MPa: 1,396 N·m (full displacement)

• Rated Speed: 65 rpm

• Speed Range: 0–140 rpm

• Valving Type: Dual displacement valving module (D21 code)

• Mounting Flange: F08 mounting configuration

• Shaft Configuration: 1720 output end

• Anti-Skid Option: TwinLock™ available

• Motor Type: Wheel motor / shaft 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 MS08-2-D21 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 1,396 N·m at 10 MPa and rated torque of 3,490 N·m at full displacement, the motor operates smoothly across the 0–140 rpm speed range without stick-slip. High startup torque ensures reliable starting under load, making it ideal for wheel-drive and tool drive applications.

2. Dual Displacement Design for Wide Operating Range

The MS08-2-D21 features a dual-displacement cam ring design with on-line switching between 934 ml/r full displacement and 467 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/MSE08 series employs Poclain’s modular design concept, allowing displacement group, flow-distribution module, brake module and output-end module to be reconfigured. The modular design facilitates use in demanding applications across construction equipment, material handling, agriculture, environment, mining, rail, marine and industry. The F08 mounting configuration supports both wheel-drive and shaft-output mounting for skid steer loaders, harvesters, road rollers and more. Optional TwinLock™ integrated anti-skid provides differential locking via hydraulic control for improved traction.

4. High-Precision Cam Ring and High Radial Load Capacity

The MS08-2-D21 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 MS08-2-D21-F08-1720-8EJA 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 MS08 series exactly, enabling direct replacement without pipework or interface modification.

Application Areas

The MS08/MSE08 series is widely deployed in heavy-duty travel and tool drives:

• Construction: skid steer loaders (Caterpillar 906/908/299D), wheel loaders (Volvo L45/L50, JCB 409/411), telescopic handlers (JCB TM180), road rollers

• Agriculture: combine harvesters (Claas Lexion series), self-propelled sprayers (John Deere 4630/4730, Case IH Patriot 3230/3340, Fendt Rogator 600, Amazone Pantera 4502, Agrifac Condor, Hardi Alpha Evo)

• Mining: roadheader star wheel drives, subsurface loaders, coal mining machinery travel drives

• Material Handling: heavy-duty forklifts, beam carriers, aerial work platforms

• 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. Mounting Flange Surface Inspection: The MS08-2-D21-F08-1720 features F08 mounting configuration. Periodically inspect the output flange plane and wheel/tool-end 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.

5. Periodic Piston Group and Cam Ring Inspection: As a radial piston motor, the MS08-2-D21’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.