Clark GCS Forklift Service Manual (SM520R)

A Clark GCS forklift usually spends its days loading trucks, feeding production lines, and shuttling pallets in tight warehouses. This service manual is what I’d keep open when I need to trace a hydraulic issue, chase an electrical fault, or strip down a major component without guessing. If, for example, the mast won’t lift under load or the steer axle feels loose, this book walks you through a logical check‑and‑verify process so you can confirm the fault before you start unbolting parts.

Applications & Use Cases

Systematic diagnostics when you’ve got warning symptoms like weak lift, uneven braking, or intermittent starting.
Disassembly and reassembly guidance to avoid missing fasteners, misrouting hoses, or damaging seals.
Adjustment checks for linkages, chains, and controls so the truck runs smoothly and doesn’t eat components early.
Verification steps after a repair to confirm pressures, movements, and responses are within a safe, usable range.
Planning workshop workflow, from isolating the truck to final test drive, so downtime and rework stay low.

FAQ

Q: Is this manual practical to use on a tablet in the shop?

A: Yes, it’s well-suited to a tablet or laptop; you can zoom diagrams and use search instead of flipping oily pages.

Q: Should I still print pages from it?

A: I usually print the specific procedures I’m doing that day, mark notes on them, then toss them once the job’s confirmed good.

Safety Note

Always secure the forklift, relieve stored energy, and use proper supports before working under or around any raised component.

📘 Show Index

Clark GCS Forklift Index:

SERVICE MANUAL SM-520R
Foreword
Contents
About This Manual
Part 1 General Information
Safe Maintenance Practices
Safety Signs and Messages
General Precautions
Product Identification
Part 2 Specifications
2.1 Service Specifications
Product Specification Changes
Part 3 Planned Maintenance
3.1 PM Schedules
3.2 Planned Maintenance Procedures PM Program
3.3 Machine Jacking and Blocking
Part 4 Engine
4.1 Engine Maintenance – Oil and Filter Change
4.2 Engine Troubleshooting Gasoline/LPG and Diesel
4.3 Engine Tune-Up Gasoline/LPG &n Diesel
4.4 Ignition Timing Procedures
4.5 Engine Valve Clearance Adjustment
4.6 Engine Compression Pressure Test – (Gasoline/LPG & Diesel)
4.7 Engine RPM, Vacuum & Stall Tests
4.8 Cooling System
4.9 Engine Air Cleaner
4.10 Engine Adjustments
4.11 Engine Removal
4.12 Engine Components GC(P)X, MB, MC Models – 4G54 [2.6L] Engine
4.13 Engine Components G(P)X-C, I Models – TM(D)27 [2.7L] Engine
4.14 Engine Components WC Models – D176GA [2.9L] Engine
Part 5 Fuel System
Fuel Tank Installation – Gasoline/Diesel
5.1 Fuel Systems Maintenance
5.2 LPG Fuel System
5.3 Diesel Fuel Injection System TMD27 [2.7L] Diesel Engine
5.4 Carburetor Gasoline – 4654 [2.6L] Engine
5.5 Carburetor Overhaul Gasoline – TM27 [2.7L] Engine
5.6 Carburetor Overhaul Gasoline – D176GA [2.9L] Engine
5.7 LPG Carburetor IMPCO Model CA1 00 Carburetor Assemblies
5.8 LPG Carburetor IMPCO Model CA50 Carburetor Assembly
5.9 LPG Vaporizer-Regulator IMPCO Model J Converter
5.10 LPG Fuel Lock-Off Valve IMPCO Model VFF 30
Part 6 Electrical System
6.1 Electrical System Wiring
6.2 Ignition System Troubleshooting
6.3 Ignition System Maintenance
6.4 Ignition System 4G54 [2.6L] Engine
6.5 Ignition System TM27 [2.7L] Engine
6.6 Ignition System D176GA [2.9L] Engine
6.7 Electronic Ignition Conversion Per-Lux /gnito@ for D176GA [2.9L] Engine
6.8 Alternator Maintenance
6.9 Alternator – Delco 103
6.10 Alternator – Motorola 9DB
6.11 Starting System Troubleshooting
6.12 Starter Motor Troubleshooting
6.13 Starter Maintenance – Delco WC Model, D176GA [2.9L] Engine
6.14 Starter Maintenance Direct-Drive (Type 1) – 4G54 [2.6L] Engine
6.15 Starter Maintenance Reduction-Type (Type 2) – 4654 [2.6L] Engine
6.16 Starter Maintenance G( P)X-C, I Models, TM(D)27 [2.7L] Engine
Part 7 Transaxle
SPIRAL BEVEL AND HYPOID TOOTH BEARING CONTACT CHART
7.1 Transaxle Maintenance – Fluid and Filter Change
7.2 Transmission Troubleshooting
7.3 Transmission Pressure Checks
7.4 Transaxle Mounting Removal/Installation
7.5 Transaxle Overhaul General Procedures
7.6 TAI 8 Transaxle
7.7 HR500 Transaxle 11FHR510/511 l-Speed
7.8 HR600 Transaxles 11 FHR61 O/61 l/61 2 1 -Speed 11 FH R620/621 2-Speed
7.9 HR620 Transmission Overhaul 11 FHR620/621 2-speed transaxle (*)
7.10 HR610 Transmission Overhaul 11FHR610/611/612 l-speed transaxle
7.11 Drive Axle Overhaul HR600 Series Transaxles
7.12 Directional Control Linkage Transmission Shift Controls
Part 8 Brakes
8.1 Service Brake & Inching Systems
8.2 Brake & Inching System Type 1 – Single Master Cylinder
8.3 Brake Bleeding Procedures Type 1 – Single Master Cylinder
8.4 Brake & Inching System
8.5 Brake Bleeding Type 2 – Dual Master Cylinders TA18 Transaxle
Part 9 Steering System
Power Steering Lines Installation MB, MC, WC, I Models -(Type 1/7A) Steer Axle
Steering System/Main Hydraulic Lines – HR500 & HR600 Transaxle
Power Steering Lines Installation G(P)X, G(P)X-C, MC, I Models -(Type 2) Steer Axle
9.1 Power Steering System Relief Pressure Setting
9.2 Steering Column and Valve (Steering Gear)
9.3 Steering Column Removal/Installation
9.4 Steering Valve Overhaul (Steering Control Unit)
9.5 Steer Axles
9.6 Steer Axle Wheel Bearing Maintenance
9.7 Steer Axle Removal/Installation
9.8 Steer Axle Overhaul Type 1)
9.9 Steering Cylinder Overhaul (Type 1 & IA, Style 7,2 & 3)
9.10 Steer Axle Overhaul (Type 1A)
9.11 Steering Cylinder Overhaul (Type IA, Style 4)
9.12 Steer Axle Overhaul (Type 2)
9.13 Steering Cylinder Overhaul (Type 2 Steer Axle)
Part 10 Hydraulic System
Hydraulic System Schematic Diagram GC(P)X, GCS/GPS 17-30
Main Hydraulic System
Description and Operation
Parts Nomenclature Steering Priority Demand (Flow Control) Valve
Parts Nomenclature Main Hydraulic Lines G(P)X, G(P)X-C Models – TA18 Transaxle
Parts Nomenclature Main Hydraulic/Steering Lines G(P)X, G(P)X-C Models – TA18 Transaxle
Parts Nomenclature Main Hydraulic Lines MB, MC, WC, I Models – HR500,HR600Transaxle
Parts Nomenclature Main Hydraulic Lines MB, MC, WC, I Models – HR500, HR600 Transaxle
Parts Nomenclature Lift and Tilt Lines
10.1 Hydraulic Sump – Fluid and Filter Change
10.2 Hydraulic System Relief Pressure Check & Adjustment
10.3 Main Hydraulic Pump Removal/Installation
10.4 Main Hydraulic Pump Overhaul
10.5 Main Hydraulic Control Valve Removal/Installation
10.6 Main Hydraulic Valve Overhaul
10.7 Tilt Cylinder Maintenance
Part 11 Wheels & Tires
Cushion Tire Nomenclature
Pneumatic Tire Nomenclature
Pneumatic Tire Nomenclature
11.1 Cushion Tire and Wheel Maintenance
11.2 Pneumatic Tire and Wheel Maintenance
Part 12 Counterweight & Chassis
12.1 Counterweight Maintenance
12.2 Chassis Components
Part 13 Uprights
13.1 Upright Maintenance
13.2 High Visibility Standard Upright (HIVIS Std)
13.3 Triple Stage Upright (TSU)
Part 14 Index
14.1 Listing by Section Contents
14.2 Subject Index