maximal FD80T Troubleshooting guide

5-10t Internal Combustion Counterbalance Forklift Truck Operation & Maintenance Manual
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Introduction
This manual has mainly introduced the items related to performance, structure, operation,
maintenance, as well as service, and other aspects of M portfolio 5-10t forklift trucks, in order
for operators to understand the forklift trucks, and to use and maintain the trucks correctly.
During the application of forklift trucks, user’s operators and equipment management
personnel involved shall carefully observe the requirements and specifications for forklift
trucks in this manual, for the forklift trucks to regularly maintain a good technical condition.
Due to our continuous improvement of the forklift truck products, the items of this manual are
subject to alteration and may vary slightly from the real forklift trucks without prior notice,
for which your kind understanding is expected.
Note: The type code in this manual is different from the model on product data plate and
certificate of conformity. The type code of this series of trucks has covered engine and its
modification code.
Example:
FD50T — M W F
Isuzu 6BG1 Engine
Imported
Maximal
Model

5-10t Internal Combustion Counterbalance Forklift Truck Operation & Maintenance Manual
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Table of Contents
Introduction ...............................................................................................................................................1
Table of Contents......................................................................................................................................1
I. Safety Rule for Drive and Operation of Forklift Truck..................................................................4
II. Main Technical Parameters for Forklift Truck..............................................................................12
III. Introduction for Main Parts of Forklift Truck .............................................................................15
IV. Structure, Principle, Adjustment, and Maintenance of Forklift Truck....................................17
1. Power System .......................................................................................................................................18
1.1 Overview.............................................................................................................................................18
1.2 Engine Configuration .......................................................................................................................18
1.3 Fuel System ........................................................................................................................................21
1.3.1 Fuel Tank .........................................................................................................................................22
1.3.2 Fuel Sensor Device........................................................................................................................22
1.3.3 Fuel Filter ........................................................................................................................................23
1.4 Cooling System..................................................................................................................................23
1.5 Examination and Adjustment..........................................................................................................23
1.5.1 Air Filter...........................................................................................................................................24
1.5.2 Fuel Filter.........................................................................................................................................24
1.5.3 Engine Oil Filter.............................................................................................................................25
1.5.4 Cooling System ..............................................................................................................................25
1.5.5 Fastening of Bolts for Engine Cylinder Head..........................................................................26
1.5.6 Adjustment of Valve Clearance...................................................................................................27
1.5.7 Confirmation of Ignition Time for Fuel Injection ...................................................................28
1.5.8 Adjustment of Ignition Time for Fuel Injection.......................................................................29
1.5.9 Determination of Compression Pressure...................................................................................29
1.5.10 Exhaust of Injection Pump.........................................................................................................29
2. Electrical System .................................................................................................................................30
2.1 Overview.............................................................................................................................................30
2.2 Brief Introduction about Operation ...............................................................................................35
2.3 Battery..................................................................................................................................................38
2.4 Wire Harness ......................................................................................................................................38
3. Transmission Device...........................................................................................................................39
3.1 Overview.............................................................................................................................................41
3.2 Torque Converter...............................................................................................................................41
3.3 Oil Feed Pump ...................................................................................................................................43
3.4 Hydraulic Clutch ...............................................................................................................................43
3.5 Control Valve and Inching Valve....................................................................................................45
3.6 Oil Circult System for Torque Converter .....................................................................................46
3.7 Notices during Failure Occurrence with Forklift Truck............................................................48
3.8 Failure Removal ................................................................................................................................48
4. Drive Axle .............................................................................................................................................55
4.1 Overview.............................................................................................................................................55
4.2 Speed Differential..............................................................................................................................55
4.3 Wheel-sided Reducer........................................................................................................................58

5-10t Internal Combustion Counterbalance Forklift Truck Operation & Maintenance Manual
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4.4 Failure Removal ................................................................................................................................60
4.5 Maintenace Data................................................................................................................................61
5. Brake System........................................................................................................................................62
5.1 Overview.............................................................................................................................................63
5.2 Power Brake .......................................................................................................................................64
5.2.1 Brake Pedal Device .......................................................................................................................64
5.2.2 Brake Valve .....................................................................................................................................67
5.2.3 Energy Accumulator......................................................................................................................68
5.3 Vacuum Power Brake .......................................................................................................................70
5.3.1 Vacuum Booster and Brake Master Cylinder...........................................................................70
5.3.2 Method for Installation of Vacuum Booster and Brake Master Cylinder Assembly........73
5.3.3 User Notices....................................................................................................................................74
5.3.4 Failure and Cause Analysis..........................................................................................................74
5.4 Wheel Brake .......................................................................................................................................74
5.4.1 Wheel Brake (For 5-7t Trucks) ...................................................................................................75
5.4.2 Wheel Brake (For 8-10t Trucks).................................................................................................78
5.5 Parking Brake.....................................................................................................................................78
5.6 Failure Removal ................................................................................................................................81
6. Steering System....................................................................................................................................82
6.1 Steering Unit.......................................................................................................................................84
6.1.1 Overview..........................................................................................................................................84
6.1.2 Operating Principle........................................................................................................................85
6.1.3 Application Requirements............................................................................................................86
6.1.4 Examination and Maintenance of Steering Unit......................................................................87
6.1.5 Failure and Removal for Steering Unit......................................................................................89
6.2 Examination after Reassembly of Steering System: ..................................................................91
6.3 Failure Removal for Steering System ...........................................................................................93
6.4 Steering Axle ......................................................................................................................................93
6.4.1 Steering Axle Body........................................................................................................................93
6.4.2 Left-Right Steering Knuckle Assembly.....................................................................................93
6.4.3 Wheel Hub.......................................................................................................................................94
6.4.4 Steering Cylinder ...........................................................................................................................94
7. Hydraulic System ................................................................................................................................96
7.1 Overview.............................................................................................................................................97
7.2 Oil Pump .............................................................................................................................................97
7.3 Multi-way Valve ................................................................................................................................97
7.4 Operation of Multi-way Valve ........................................................................................................98
7.5 Work of Main Safety Valve .............................................................................................................99
7.6 Work of Tilt Auto-locking Valve ..................................................................................................100
7.7 Control Device of Multi-way Valve ............................................................................................100
7.8 Oil Tank.............................................................................................................................................100
7.9 Oil Circuit of Hydraulic System...................................................................................................101
7.10 Maintenance ...................................................................................................................................104
7.10.1 Disassembly of Multi-way Valve ...........................................................................................104

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7.10.2 Reassembly of Multi-way Valve.............................................................................................104
7.10.3 Notices .........................................................................................................................................105
8. Lift Cylinder and Tilt Cylinder .......................................................................................................105
8.1 Lift Cylinder.....................................................................................................................................105
8.2 Isolating Valve..................................................................................................................................108
8.3 Limiting Valve..................................................................................................................................108
8.4 Tilt Cylinder...................................................................................................................................... 110
9. Lifting System.................................................................................................................................... 111
9.1 Overview...........................................................................................................................................112
9.2 Outer & Inner Mast......................................................................................................................... 112
9.3 Fork Carriage.................................................................................................................................... 112
9.4 Adjustment of Lifting System....................................................................................................... 112
9.4.1 Gasket Adjustment for Lift Cylinder Head.............................................................................112
9.4.2 Height Adjustment for Fork Carriage ...................................................................................... 113
9.5 Mounting Positions of Rollers...................................................................................................... 114

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I. Safety Rule for Drive and Operation of Forklift Truck
I. The drivers and management personnel of forklift truck must bear in mind “Safety First”,
and conduct safety operation and standard operation according to the “Operation and
Maintenance Manual” for the forklift truck.
II. Conveyance of Forklift Truck
It is required to pay attention to the following items when motor vehicle is used to load and
convey the forklift truck.
1. Skid the parking brake.
2. Both the front and rear parts of mast and counterweight shall be properly fixed using steel
wire. The corresponding positions of front and rear tyres shall be firmly wedged up using
wedge blocks.
3. The forklift truck shall be listed according to the marked position on the “Lift Data Plate”
for forklift truck at the lifting time.
III. Storage of Forklift Truck
1. Drain the fuel completely (It is not to be drained if coolant is the antirust and antifreeze
fluid.)
2. Coat the surface of unpainted parts with antirust oil, and coat the lift chain with lubricating
oil.
3. Drop the mast to the lowest position.
4. Skid the parking brake.
5. Wedge up the front and rear tyres properly using wedge blocks.
IV. Preparation prior to Use
1. Avoid examining fuel, oil leak, oil level, and examining electrical instrument in a place
with an open fire, and avoid adding fuel during operation.
2. Examine the air pressure of tyres.
3. It is required to place the handle for forward/backward gear at the middle position (zero
gear position).
4. Don’t smoke when fuel system is working and when battery is being examined.
5. Examine the status of respective handles and pedals.
6. Get properly prepared for startup.
7. Loosen the parking brake.
8. Perform the test actions such as rise and fall of mast, forward and backward tip, steering,
and brake.
V. Operation of Forklift Truck

5-10t Internal Combustion Counterbalance Forklift Truck Operation & Maintenance Manual
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1. Only the drivers who have been trained and hold driving license are allowed to drive the
truck.
2. The operators shall wear shoes, helmet, clothes, and gloves that can be used for safety
protection.
3. Examine respective controls and warning devices before truck is driven, and the truck shall
be operated after it has been repaired in the case when any damage or defect is found.
4. During conveyance, the load shall not exceed the specified value, the fork must be
completely inserted into the underside of cargo, and the cargo must be uniformly placed on
the fork. It is not allowed to pick up cargo using a single fork tip.
5. Smoothly perform start, steering, running, brake, and, and slow down at turning, on wet or
smooth pavements.
6. It is required to place cargo as low as possible, and to keep the mast tilt backwards, when
cargo is loaded for driving.
7. It is required to be careful during driving on a ramp. It is required to drive forward during
upgrade and drive reversely during downgrade, when the truck is driven on a ramp larger than
1/10. Turning shall be avoided by all means, and please never perform loading-unloading
operation when forklift truck is running downgrade.
8. It is required to pay attention to passengers, obstacles, and low-lying pavements, and pay
attention to the clearance above the forklift truck, during driving.
9. It is not allowed for anyone to stand on fork and it is not allowed for anyone to be carried
on truck.
10. It is not allowed for anyone to stand under the fork, or to walk under the fork.
11. It is not allowed to control the truck and attachments at any position other than the driver
seat.
12. It is required to pay attention to the fall of cargo from above, for any high lift forklift
trucks with a lifting height larger than 3m, and protective measures must be taken, when
necessary.
13. Try as much as possible to tip backward the mast for high-lift forklift trucks during work,
and it is required to perform front or back tip within the minimum range during
loading-unloading operation.
14. It is required to take a doubled care, and to drive slowly, during running on dock or on
temporary planks.
15. Driver shall not stay on the truck, when fuel is added, and the engine shall be turned off.
Ignition is to be avoided when battery or level of oil tank is examined.

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16. The forklift trucks with attachments shall be operated as loaded forklift trucks during
unloaded operation.
17. Don’t convey unfixed or loosely stacked cargo, and take care when cargo of relatively
large size is conveyed.
18. Drop the fork onto the ground, put the handle for gear position to neutral gear, and turn off
the engine or disconnect the power supply when driver leaves the truck. Pull the parking
brake device properly when truck is parked on a ramp, while wedge blocks must be used to
fill up the wheels when the truck is to be parked there for a long time.
19. It is not allowed to open radiator cover carelessly, under the condition when engine is very
hot.
20. The pressures of multi-way valve and safety valve have been properly adjusted before
delivery of forklift truck from factory, and users shall not adjust them at discretion during use,
to avoid damage of entire hydraulic system and hydraulic components due to excessively high
adjustment.
21. The value of air pressure specified on the label plate of “Tyre Air Pressure” shall be
followed for tyre air charge.
22. The maximum noise outside the forklift truck is not to be larger than 89dB (A), and
JB/T3300 shall be followed as test method.
23. Get familiar with and pay attention to the functions of various data plates on the forklift
truck.

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VI. Schematic Drawing of Instruments and Control Layout for Forklift Truck
1. Fuel Gage 13. Lift Handle
2. Indicator Light 14. Tilt Handle
3. Water Temperature Gauge 15. Parking Brake Handle
4. Hour Meter 16. Front-Rear-Gear Handle
8. Ignition Switch 19. Inching Pedal
9. Light Switch 20. Brake Pedal
10. Horn Pushbutton 21. Throttle Accelerator Pedal
11. Steering Light Switch 22. Engine Hood Stay Cable
12. Steering Wheel 23. Engine Stop Stay Cable

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VII. Routine Maintenance of Forklift Truck
1. Key Points for Startup
1) Oil quantity and oil level of hydraulic oil shall be at the middle position of scale on oil
level indicator.
2) Examine whether or not leak or damage exists with pipe, joint, pump, and valve.
3) Examine wheel brake.
a) The idle stroke of brake pedal shall be 40mm.
b) The clearance between front bottom plate and pedal shall be larger than 20mm.
4) Examine the hand brake function: When hand brake handle is thoroughly pulled, it shall be
able to be skidded on a 20% ramp (no load).
5) Instruments and Illumination Light Fittings, etc: Examine whether or not the respective
parts including instruments, illumination, connection joints, switches, and electrical circuit are
working normally.
2. Oils, Greases, and Anti-freeze Fluids Used for Forklift Truck:
Name
Original Oil
Product
Brand, Code, and Temperature of Use
Gasoline 93# or 97#
Brand of Light
Diesel Oil
0# -10# -20# -35#
Diesel Oil
Application
Temperature (℃)
≥4 ≥-5 ≥-5～-14 ≥-14～-29
Viscosity Grade 5W/30 10W/40 10W/30 15W/40
Gasoline Engine
Oil (SF)
Electronic
Injection Type
(SG)
Great Wall Application
Temperature(℃)
-30～
+40
-25～
+40
-25～+30 -25～+40
Viscosity Grade 5W/30 10W/30 15W/40 20W/50
Diesel Engine
Oil (CD)
Great Wall Application
Temperature(℃)
-30～
+30
-25～
+30
-20～+40 -15～+50
Viscosity Grade
L-HM32 Antiwear
Hydraulic Oil
L-HV32 Low Temperature
Antiwear Hydraulic oil
Hydraulic Oil Kunlun
Application
Temperature(℃)
＞-19
＞-33(in Open Air in Cold
Regions)
Torque HAIPAI 6# Torque converter oil

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converter oil
Brake Fluid
Chongqing
Yiping
4604 Synthetic Brake Fluid GB12981HZY4
Lubricating
Grease
Great Wall 3# General Lithium Base Lubricating Grease(-20℃～+120℃)
Viscosity Grade 85W/90GL-5 80W/90GL-5 Heavy-duty
Truck Gear
Oil
HAIPAI Application
Temperature(℃)
-15～+49 -25～+49
Code FD-1 FD-2 FD-2A FD-3
Anti-freeze
Fluid
Jinbai Application
Temperature(℃)
≥-25 ≥-35 ≥-45 ≥-50