Yale A7S1 User manual

Maintenance
A7S1
SERVICE MANUAL
GLP/GDP20UX, GLP/GDP25UX, GLP/GDP30UX, GLP/
GDP35UX
PART NO. 550216372 8000 YRM 2199

INTRODUCTION
The Service Manuals are updated on a regular basis, but may not reflect the latest design changes to the product.
Updated technical service information may be available from your local authorized YALE® distributor. Service
Manuals provide general guidelines for maintenance and service and are intended for use by trained and
experienced technicians. Failure to properly maintain equipment or to follow instructions contained in the Service
Manual could result in damage to the products, personal injury, property damage or death.
FOREWORD
This manual describes the structure and working principles of the 2-3.5T internal combustion forklift truck and
provides instructions for servicing and maintenance.
To ensure safety and get the best out of your forklift, all operators, equipment managers and maintenance
personnel should carefully read this manual.
Only trained and qualified personnel are permitted to carry out servicing and repairs on the forklift truck.
Series Model Engine Transmission
2-2.5T
GLP/GDP20-25UX NISSAN K21 LPG YQXD30H(PHF)
GLP/GDP20-25UX NISSAN K21 GAS YQXD30H(PHF)
GLP/GDP20-25UX NISSAN K21 DUAL YQXD30H(PHF)
GLP/GDP20-25UX NISSAN K25 LPG YQXD30H(PHF)
GLP/GDP20-25UX NISSAN K25 GAS YQXD30H(PHF)
GLP/GDP20-25UX NISSAN K25 DUAL YQXD30H(PHF)

Series Model Engine Transmission
2-2.5T
GLP/GDP20-25UX MITSUBISHI S4S-455 YQXD30(PHF)
GLP/GDP20-25UX PSI 4G64 2.4L YQXD30(PHF)
GLP/GDP20-25UX XINCHAI 4D27G31 YQXD30A(PHF)
GLP/GDP20-25UX YANMAR 4TNE92 YQXD30(PHF)
3-3.5T
GLP/GDP30-35UX NISSAN K25 LPG YQXD30H(PHF)
GLP/GDP30-35UX NISSAN K25 GAS YQXD30H(PHF)
GLP/GDP30-35UX NISSAN K25 DUAL YQXD30H(PHF)
GLP/GDP30-35UX MITSUBISHI S4S-455 YQXD30(PHF)
GLP/GDP30-35UX PSI 4G64 2.4L YQXD30(PHF)
GLP/GDP30-35UX XINCHAI 4D27G31 YQXD30A(PHF)
GLP/GDP30-35UX YANMAR 4TNE94 YQXD30(PHF)
GLP/GDP30-35UX YANMAR 4TNE98 YQXD30(PHF)
NOTE: DUAL designates DUAL FUEL or BI-FUEL.

©2021 Yale Materials Handling Corp.
TABLE OF CONTENTS
Forklift Truck Main Parts......................................................................................................................................... 1
Description of Forklift Truck Main Parts................................................................................................................1
Forklift Main Technical Parameters......................................................................................................................... 2
Main Technical Parameters.................................................................................................................................. 2
Power System......................................................................................................................................................... 5
Engine System......................................................................................................................................................5
Engine Overview................................................................................................................................................5
Fuel System....................................................................................................................................................... 6
Fuel Tank.........................................................................................................................................................7
Fuel Level Sensor............................................................................................................................................8
Maintenance of Fuel System...........................................................................................................................9
Fuel filter service...........................................................................................................................................9
Hydraulic Transmission Case and Torque Converter............................................................................................10
Overview.............................................................................................................................................................10
Torque Converter................................................................................................................................................ 11
Hydraulic Clutch..................................................................................................................................................12
Control Valve, Safety Valve, and Inching Valve.................................................................................................. 13
Transmission Case............................................................................................................................................. 15
Transmission Pump............................................................................................................................................ 15
Transmission hydraulic schematic .....................................................................................................................15
Speed Reducer and Speed Differential.............................................................................................................. 16
Speed Reducer................................................................................................................................................ 16
Speed Differential.............................................................................................................................................17
Towing the Lift Truck...........................................................................................................................................17
Oil Inlet/Outlet Connection Location................................................................................................................... 17
Drive Axle..............................................................................................................................................................18
Overview.............................................................................................................................................................18
Maintenance of Drive Axle..................................................................................................................................19
Steering System....................................................................................................................................................20
Steering System................................................................................................................................................. 20
Overview.......................................................................................................................................................... 20
Hydraulic Steering Gear Assembly................................................................................................................20
Steering Cylinder...........................................................................................................................................21
Inspection of Reassembled Steering System.................................................................................................. 22
Troubleshoot Steering System.........................................................................................................................23
Steering and Drive Axle Information..................................................................................................................... 24
Steering Axle...................................................................................................................................................... 24
Overview.......................................................................................................................................................... 24
Steering Knuckle and Steering King Pin.......................................................................................................... 25
Steering Wheel Bearing Pre-load Information..................................................................................................26
Brake System........................................................................................................................................................26
Overview.............................................................................................................................................................27
Brake Master Cylinder........................................................................................................................................ 27
Wheel Brake....................................................................................................................................................... 27
Automatic Brake Adjuster................................................................................................................................... 31
Manual Brake......................................................................................................................................................32
Adjustment of Brake Pedal................................................................................................................................. 32
Maintenance....................................................................................................................................................... 32
Disassemble, Wheel Brake..............................................................................................................................33
Examination of Wheel Brake............................................................................................................................35
Assemble, Wheel Brake...................................................................................................................................36
Operating Test Automatic Clearance Regulator...............................................................................................38
Table of Contents
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TABLE OF CONTENTS (Continued)
Troubleshoot Wheel Brake...............................................................................................................................39
Hydraulic System.................................................................................................................................................. 41
Overview.............................................................................................................................................................41
Steering Control Unit.......................................................................................................................................... 42
Multi-way Valve and Priority spool .....................................................................................................................42
Operation of Spool Valve................................................................................................................................. 42
Neutral Position............................................................................................................................................. 42
Spool Valve (Pushed In):...............................................................................................................................43
Spool Valve (Pulled out):............................................................................................................................... 43
Primary Relief Valve and Priority Spool........................................................................................................... 43
Inclined Auto-Lock Valve..................................................................................................................................44
Hydraulic System Main Oil Circuit ..................................................................................................................... 45
Lift Cylinder.........................................................................................................................................................47
Velocity Fuse...................................................................................................................................................... 49
Tilt Cylinder.........................................................................................................................................................50
Maintenance of Hydraulic Pump.........................................................................................................................51
Disassemble, Main Oil Pump...........................................................................................................................51
Inspection and Repair...................................................................................................................................... 51
Assemble, Main Oil Pump................................................................................................................................54
Test...................................................................................................................................................................55
Troubleshoot Hydraulic System..........................................................................................................................59
Lifting System........................................................................................................................................................60
Safety Procedures When Working Near Mast....................................................................................................60
Overview.............................................................................................................................................................62
Inside and Outside Masts................................................................................................................................... 62
Carriage..............................................................................................................................................................63
Adjustment of Lifting System.............................................................................................................................. 63
Electrical System...................................................................................................................................................64
Overview.............................................................................................................................................................64
Power supply system....................................................................................................................................... 64
Starting system................................................................................................................................................ 64
Ignition system (ICE forklift truck).................................................................................................................... 64
Preheating system (diesel forklift truck)........................................................................................................... 64
Dash Instrument Display System.....................................................................................................................65
Lighting, sound and alarm system................................................................................................................... 65
Electrical Box......................................................................................................................................................65
Battery................................................................................................................................................................ 65
Description and Summary of Basic Truck Operations........................................................................................ 65
Introduction to the Power Distribution Module (PDM)........................................................................................ 67
Electrical Schematics..........................................................................................................................................67
Troubleshoot Electrical System.......................................................................................................................... 81
Troubleshooting............................................................................................................................................... 81
Drive, Operation, and Routine Maintenance of Forklift Truck............................................................................... 82
Cooling System Troubleshooting and Service....................................................................................................82
Coolant level check..........................................................................................................................................82
Flushing the cooling system.............................................................................................................................82
Adding antifreeze/coolant.................................................................................................................................82
Cleaning the radiator........................................................................................................................................82
Oils Used for Forklift Truck................................................................................................................................. 83
Hydraulic Oil Gauge and Hydraulic Oil fill...........................................................................................................83
General inspection requirements..................................................................................................................... 83
Fill Level Requirements....................................................................................................................................83
Table of Contents
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TABLE OF CONTENTS (Continued)
Lubrication System............................................................................................................................................. 83
PDM Schematics...................................................................................................................................................85
Table of Contents
iii

Forklift Truck Main Parts
DESCRIPTION OF FORKLIFT TRUCK
MAIN PARTS
System Subassemblies
Power System Transmission System Torque Converter Hydraulic
Transmission Case
Speed Reducer or
Speed Differential
Drive Axle Steering System Steering Axle Lifting System
Control System
Brake and Inching
Control (Hydraulic
Truck)
Hydraulic System
Parking Brake
Throttle Control
Steering Control
Electrical System
8000 YRM 2199 Forklift Truck Main Parts
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Forklift Main Technical Parameters
MAIN TECHNICAL PARAMETERS
Figure 1. Outside Drawing of Forklift Truck(LPG/DUAL)
Forklift Main Technical Parameters 8000 YRM 2199
2

Figure 2. Outside Drawing of Forklift Truck (Diesel engine/gasoline engine)
NOTE: Truck with diesel engine is shown. Other
trucks are similar. The values in the parameter tables
are for standard configuration only. Always consult the
nameplate to see the values of a specific truck.
8000 YRM 2199 Forklift Main Technical Parameters
3

Table 1. Technical Parameters
Parameter Model
GLP/GDP20UX GLP/GDP25UX
Engine Model 4G64 2.4L 4G64 2.4L
Manufacturer PSI PSI
Power Source GAS/LPG GAS/LPG
Rated Capacity 2000 kg (4409.2 lb) 2500 kg (5511.6 lb)
Load Center 500 mm (19.7 in.) 500 mm (19.7 in.)
Lifting Height 3000 mm (118.1 in.) 3000 mm (118.1 in.)
Free Lift Height 160 mm (6.3 in.) 160 mm (6.3 in.)
Mast Tilt Angle Forward/Back 6/12° 6/12°
Max Lifting Speed No-Load 580 mm/s (1.9 ft/s) 580 mm/s (1.9 ft/s)
Full-Load 550 mm/s (1.8 ft/s) 550 mm/s (1.8 ft/s)
Running Speed Forward 20 kph (12.4 mph) 20 kph (12.4 mph)
Back 20 kph (12.4 mph) 20 kph (12.4 mph)
Max Traction Force No-Load 15000 N (3372.1 lbf) N
( lbf)
15000 N (3372.1 lbf)
Full-Load 17000 N (3821.8 lbf) 17000 N (3821.8 lbf)
Gradeability No-Load 20% 20%
Full-Load 20% 20%
Min Turning Radius 2290 mm (90.2 in.) 2350 mm (92.5 in.)
Minimum Turning Radius Width K 3966 mm (156.1 in.) 4026 mm (158.5 in.)
Total Length L （Without Fork）2535 mm (99.8 in.) 2596 mm (102.2 in.)
Total Width W 1150 mm (45.3 in.) 1150 mm (45.3 in.)
Total Height D （Mast Retracted）2010 mm (79.1 in.) 2010 mm (79.1 in.)
Total Height E （Mast Extended）3990 mm (157.1 in.) 3990 mm (157.1 in.)
Wheelbase F 1600 mm (63 in.) 1600 mm (63 in.)
Track Width Front Q1 970 mm (38.2 in.) 970 mm (38.2 in.)
Front Q2 980 mm (38.6 in.) 980 mm (38.6 in.)
Front Overhang B 476 mm (18.7 in.) 476 mm (18.7 in.)
Rear Overhang C 484 mm (19.1 in.) 545 mm (21.5 in.)
Fork Dimension Length 1070 mm (42.1 in.) 1070 mm (42.1 in.)
Width 100 mm (3.9 in.) 100 mm (3.9 in.)
Height 40 mm (1.6 in.) 40 mm (1.6 in.)
Fork Spacing Adjustable Range 250-1000 mm
(9.8-39.4 in.)
250-1000 mm
(9.8-39.4 in.)
Ground Clearance （Bottom Of Mast） 125 mm (4.9 in.) 125 mm (4.9 in.)
Total Weight 3390 kg (7474 lb) 3650 kg (8046.9 lb)
Forklift Main Technical Parameters 8000 YRM 2199
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Power System
ENGINE SYSTEM
NOTE: Engine availability may be different in your
market. Contact your local Hyster dealer for more
information.
Engine Overview
Refer to Table 2 for the imported DUAL FUEL and
LPG used for 2.0-3.5t forklift trucks in A series.
Table 2. Gasoline Engine (2.4)
Model PSI 4G64-2.4L
Type 4-Stroke, Water-Cooling, Straight-Line, and Valve in Head
Number of Cylinders 4
Cylinder Diameter × Stroke 86.5 × 100 mm (3.41 × 3.94 in.)
Total Displacement I 2.35 liter (143.4 in.3)
Compression Ratio 9.5
Rated Power/
Speed kw(ps)/rpm
Gasoline Engine
48/2700（kw/rpm）
64.4/2700（hp/rpm）
LPG Engine
46/2700（kw/rpm）
61.7/2700（hp/rpm）
Max Torque/Speed
Gasoline Engine
170/2400（N.m/rpm）
125.4/2400（lbf·ft/rpm）
LPG Engine
168/1600（N.m/rpm）
123.9/1600（lbf·ft/rpm）
No-Load Min Speed 750 rpm
Fuel Specific Consumption 290 g/psh (.096 g/hph)
Total Length × Total Width × Total
Height
677.4 × 543.6 × 711.0 mm
(26.7 × 21.4 × 28.0 in.)
Movement Direction In Clockwise Direction Looking from the End of Fan
Firing Order 1-3-4-2
8000 YRM 2199 Power System
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Table 2. Gasoline Engine (2.4) (Continued)
Model PSI 4G64-2.4L
Valve Timing
Inlet Valve Open
before Top Dead
Center (BTDC)
8°
Inlet Valve Close
after Bottom Dead
Center (ABDC)
48°
Exhaust Valve
Open before
Bottom Dead
Center (BBDC)
31°
Exhaust Valve
Close after Top
Dead Center
(ATDC)
36°
Timing belt change interval 6000 hrs
Cooling System Forced Circulation Water Cooling
Lubricating System Forced Lubrication
Gasoline Pump Membrane Type
Air Filter Paper Element Filter
Engine Oil Pump Gear Type
Oil Rough Filter Paper Filtration
Water Pump Centrifugal Type
Thermostat Wax Type
Generator Voltage 12V
Current 70A
Starter Voltage 12V
Output Power 1.2 kW (1.61 hp)
Battery Voltage 12V
Capacity 60Ah
Referential Data
Lubricating Oil 4.5 liter (4.7 qt)
Coolant Engine 3.5 liter (3.7 qt)
Radiator 3.5 liter (3.7 qt)
Refer to the engine operation and maintenance
manuals for more information about engines used for
2-3.5t forklift trucks.
Fuel System
Fuel system is composed of fuel tank, fuel quantity
sensor, and fuel quantity indicator. See Figure 5 and
Figure 6.
Power System 8000 YRM 2199
6

Fuel Tank
The fuel tank is a welded structure contained within
the frame of the forklift truck. The capacity of fuel tank
for 2-2.5t is 59 liter (15.6 gal), and 65 liter (17.2 gal) for
3-3.5t forklift trucks. The Fuel Level Sensor is fitted on
the tank cover of fuel tank to detect the fuel level. See
Figure 3 or Figure 4.
1. PORT SEALED
2. FUEL LEVEL
3. FLOAT RISE
4. FLOAT DROP
5. OIL INLET
6. GAS FILTER
Figure 3. Fuel Tank (Gasoline Forklift Truck)
8000 YRM 2199 Power System
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Figure 4. Fuel Tank (LPG Forklift Truck)
Fuel Level Sensor
The Fuel Level Sensor is used to convert the
remaining fuel quantity in fuel tank into voltage. This is
to monitor the amount of fuel currently in the fuel tank.
Refer to Figure 5. The value of resistance will change
when the float moves up and down, depending on the
fuel level. Resistance is controlled by using steel wire
that is fabricated into the slide. The fuel quantity inside
the fuel tank can be read on the instrument panel
through the electromagnetic fuel gauge.
1. FUEL LEVEL
2. FLOAT RISE
3. FLOAT DROP
Figure 5. Fuel Level Sensor
Power System 8000 YRM 2199
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Fuel Position Resistance (Ω)
FULL 180±5
½ 95±5
EMPTY 10±½
Maintenance of Fuel System
The fuel system is to be maintained and serviced once
for every 100 work hours, with the following method.
The fuel tank must be cleaned once every 600 work
hours.
Fuel filter service
The fuel filter is used to remove dust and impurities in
fuel. The fuel filter is located between the fuel tank and
the gasoline pump (gasoline engine) or oil delivery
pump and oil injection pump (diesel engine).
1. STEEL TUBE CLAMP
2. FUEL FILTER
3. HIGH PRESSURE FUEL PUMP
4. FUEL PUMP FITTING AND GASKET
5. FUEL PUMP MANIFOLD
6. 6 STOR 5/16 SAE FITTING
7. 3 STOR 5/16 SAE FITTING
Figure 6. Fuel Filter (PSI 4G64-2.4L Engine)
The fuel filter must be changed every 400 hours or
every 6 months.
8000 YRM 2199 Power System
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Hydraulic Transmission Case and Torque Converter
Torque Converter
Type Three-Element, Single-Stage, and
Two-Phase Type
Torque Ratio 2.8-3.0:1
Pressure Range 0.5-0.7 MPa (72.5-101.5 psi)
Oil Feed Pump
Type Internal Meshing Gear Type
Flow Rate 27 l/min (1.5 MPa x 2000 rpm)
7.1 g/min (217.6 psi x 2000 rpm)
Hydraulic Transmission Case
Type Power Gear Shift
Speed Ratio Forward 17.5:1
Reverse 17.5:1
Pressure Range 1.2 to 1.5 MPa (174 to 218 psi)
Hydraulic Clutch
Brake Shoes Outer Diameter x Inner
Diameter x Thickness
125 x 81 x 2.7 mm (4.9 x 3.2 x
0.1 in.)
Brake Shoes Frictional Surface Area 71 cm2 (11 in2)
Pressure Range 1.1 to 1.4 MPa (160 to 203 psi)
Weight 165 kg (363.8 lb)
Oil Capacity
Transmission (Total) 8.6 liter (9.1 qt)
Transmission (Drain and fill) 4.7 liter (5 qt)
Radiator 1 liter (1.1 qt)
Type of Oils Used Kinematic Viscosity 5-7 cSt at 212°F
(100℃ mm2/s）
CALTEX：Torque Fluid 175; RPM
torque fluid NO.5
ESSO:Torque Fluid 47
SHELL：Rotella 10w
Clean the oil filter（coarse strainer）Every 1000 hours
Replace the oil filter（fine filter）Every 250 hours
OVERVIEW
The transmission is mounted with a torque converter
and power gear-shift transmission case (see Figure 7).
The hydraulic transmission case and torque converter
provides the following advantages:
1. The inching valve allows the truck to perform
inching operations at both high and low engine
speeds.
2. The hydraulic clutch is equipped with four pairs
of brake shoes and steel plates that have been
specially designed to be abrasion resistant.
3. The hydraulic clutch is mounted in the torque
converter to improve the transmission power
and efficiency.
4. A filter is located in the hydraulic circuit, to
screen impurities from the fluid/oil and help
keep the torque converter clean and functioning.
Hydraulic Transmission Case and Torque Converter 8000 YRM 2199
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1. GEAR SHAFT
2. TAPERED ROLLER BEARING
3. TORQUE CONVERTER HOUSING ASSEMBLY
4. OIL PUMP ASSEMBLY
5. COVER AND CONTROL VALVE ASSEMBLY
6. CLUTCH ASSEMBLY
7. BEARING PLATE
8. HOUSING
9. IDLER SHAFT
10. OUTPUT SHAFT
11. IDLER GEAR
12. OUTPUT GEAR
13. HYDRAULIC TOR-CON CONVERTER
14. INCH VALVE ASSEMBLY
15. DIFFERENTIAL ASSEMBLY
16. SPIRAL BEVEL GEAR
17. BEARING CAP
Figure 7. Hydraulic Transmission Device
TORQUE CONVERTER
The torque converter is composed of three parts, a
pump impeller, turbine, and guide pulley.
Pump impeller is driven by the input shaft. The fluid is
sprayed onto the blades of turbine and along the pump
impeller blades by centrifugal force. Torque is then
provided to output shaft. The fluid exiting the turbine
changes direction to the guide pulley. Reactive torque
is then generated to push the guide pulley causing the
output torque to be greater than the input torque. If the
fluid flows into the blades of guide pulley in reverse
direction, it causes the reactive torque to act in
reverse. This causes the torque of output shaft to be
less than the input shaft torque. To prevent this, the
clutch mounted inside the guide pulley allows the
guide pulley to rotate freely when reactive torque is
reversed.
This method of torque conversion ensures a high-
efficient and steady operation.
The torque converter for the transmission is connected
with the flywheel of engine through an elastic plate, it
turns along with the rotation of the engine. Oil fills the
torque converter. The drive gear is connected to the
pump impeller by gear teeth, this controls the oil feed
pump. The oil feed pump then supplies oil to the
torque converted and the hydraulic shifting
transmission case. The turbine is connected to the
turbine shaft with splines. Power is transmitted to the
power gear-shift transmission case through the turbine
shaft.
8000 YRM 2199 Hydraulic Transmission Case and Torque Converter
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1. OIL DRAIN PLUG
2. FLEX PLATE
3. TURBINE
4. GUIDE PULLEY
5. THRUST BEARING
6. BALL BEARING
7. RETAINER RING
8. TURBO SHAFT
9. ONE-WAY CLUTCH
10. PUMP IMPELLER
Figure 8. Torque Converter
HYDRAULIC CLUTCH
Wet multi-disk hydraulic clutch is mounted on the input
shaft of hydraulic transmission case. It distributes oil
pressure to the forward or reverse clutch through the
control valve, this causes the forward and reverse gear
shift. All the gears in transmission case are normally-
engaged gears. Each clutch is composed of alternately
assembled, four spacers (item 18, Figure 9), four
brake shoes (item 19, Figure 9), and one piston (item
2, Figure 9). The internal and external surfaces of the
piston are fitted with seal rings to ensure a proper seal.
In NEUTRAL position, the piston does not interact with
the spacer and the brake shoe. While in gear, oil
pressure controls the piston. The spacer compresses
against the brake shoe, and an the adapter transmits
power from torque converter to the driving gears
(items 4 and 6, Figure 9).
The transmission of power from torque converter to
hydraulic transmission case is as follows:
Turbine → Input Shaft Assembly → Spacer →
Brake Shoe → Forward Gear or Reversing Gear →
Output Shaft
Hydraulic Transmission Case and Torque Converter 8000 YRM 2199
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