1987 and Newer Clark OP15 Order Selector Service Manual (P/N SM566)

Clark service manual SM566 covers 1987 and newer OP15 order selector lift trucks, with standard and full free-lift Triple Stage Uprights (TSU). The factory material covers planned maintenance, system diagnosis and component repair.

Text search and schematic detail: Embedded text supports searches across the service chapters, although OCR errors and diagram labels limit coverage. PDF bookmarks link to chapters and subsections. Small labels in the main electrical schematic require zooming, and some markings remain difficult to distinguish.

• Traction control: EV-100 SCR troubleshooting tables, component tests, control-card terminal data and OP15 trimpot settings for speed control and plugging.

• Electric motors: Drive, lift-pump and steer-pump motor removal, disassembly, commutator reconditioning, bearing replacement and insulation testing.

• Drive unit and brakes: Drive-unit overhaul, gear-bearing shimming, brake-cylinder repair, system bleeding and brake interlock switch adjustment.

• Steering and hydraulics: Steering-cable service, torque-generator overhaul, steer-pump troubleshooting, main hydraulic pump testing and control-valve inspection.

• Uprights and platform: Standard and TSU removal, lift-chain adjustment, roller shimming, cylinder drift testing and free-lift cylinder repacking.

• Controls and maintenance: Battery care, control-handle and master control switch service, pallet-clamp adjustment, lubrication charts, wheel inspection and tire replacement.

Clark wrote this manual for personnel trained and authorized to perform lift-truck maintenance.

EV-100 Diagnosis and Motor Repair

Symptom tables distinguish reduced or missing motor torque, uncontrolled full power and faults in other control functions. They help technicians check external wiring, switches and contactors before condemning the control card.

The Electrical Schematic maps the truck wiring. The Function of EV100 Card Terminals table and Trimpot Location drawing for logic cards 1C3645EVL1 and L2 support electrical checks and setup. OP15 settings cover creep, controlled acceleration, current limit, plugging and 1A operation.

Contactor coverage distinguishes normally open and double-throw designs, plus the Cableform A-27185 assembly. Coil-resistance tables and accelerator-potentiometer tests complement motor insulation checks using a megger or volt-ohmmeter.

The steer-pump motor uses permanent magnets. Its service instructions warn that impact or clamping of the housing can damage the ceramic pole pieces.

Drive Unit, Brakes and Steering

The 14:1 drive unit section covers gear-bearing preload and end-play adjustment. Motor installation includes shaft alignment and total indicated runout (TIR) checks; forcing a misaligned armature shaft into the case-cover bearing can break the shaft.

The mechanically applied, hydraulically released brake has separate cylinder, pedal, bleeding and interlock procedures. Steering repair follows the cable-and-chain linkage through the directional indicator and torque generator, including matched spool-and-sleeve components and gerotor alignment.

Hydraulic Pump and Valve Service

The main lift-pump chapter covers internal inspection, reassembly and test-stand checks for pressure, flow and leakage. Pump exploded views show the sealing arrangement, while wear criteria address the gears, shafts, bushings and wear plate.

Control-valve coverage includes the solenoid lowering valves, manual emergency release, flow regulator and relief components. Maintenance notes address hydraulic-fluid cleanliness and seal condition.

Standard and Triple Stage Uprights

Separate procedures address platform removal and rail handling for each upright type. The control-handle section also distinguishes two-speed lift and lowering on TSU trucks from optional two-speed lift on two-stage trucks.

The Measuring Rail to Roller Clearance illustration supports shim selection at different upright positions. Roll-pattern checks, load testing and cylinder drift checks help evaluate binding and unwanted lowering. Cylinder repair extends to seal and wear-ring replacement, with bleeding covered for the free-lift cylinder.

Maintenance Data and Repair Scope

Planned-maintenance schedules pair functional inspections with the Maintenance Lubrication Chart, battery cleaning and critical-fastener checks. Reference data includes torque specifications for drive-unit mounting bolts and wheel lug nuts, roller clearances, electrical test values, truck dimensions and performance ratings.

Parts identification refers to a separate parts manual; additional operating instructions are in the truck's Operator's Manual. These publications are not included in this PDF.

Follow the manufacturer's safety procedures for electrical isolation, stored capacitor energy, pressurized hydraulics and securing raised uprights or platforms during service.

Service PDF and Included Pages

One printable English-language PDF contains the service publication. The 125-page PDF includes the cover (1 page), contents (1), index (4), introductory and safety material (5), and maintenance, repair and specification sections (114); these pages are all included in the total.