

The Komatsu Bulldozer D39EX-21 is a robust and efficient piece of heavy machinery designed for various earthmoving tasks. Known for its durability and performance, this bulldozer is ideal for construction and mining applications, ensuring optimal productivity and reliability on the job site.
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Find all the essential guides in one place.
Tensioning Guide
Belt-diagram
C-120 pulleys
+ 13 more
Pre-built workflows to keep your asset running smoothly.
Daily Electrical System Inspection
Replace Roller and Pulley
Install Engine B-120
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Integrate maintenance plans directly into your work orders.
Motion Industries
Applied Industrial Technologies
Electrical Brothers
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Drive Motor
B2 Rollers
Tensioning System
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Komatsu Komatsu Bulldozer D39EX-21 D39EX-21
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50 Hourly Bulldozer Maintenance
Warning: Carry out this check before operating the machine.
Prepare a container to catch the fuel that is drained.
Open drain valve (1) at the bottom inside the inspection cover on the left side at the rear of the machine and drain the water and sediment accumulated at the bottom together with fuel.
Warning: When doing this, be careful not to get fuel on yourself.
After clear fuel comes out, close drain valve (1).
4000 Hourly Bulldozer Maintenance
Water Pump Check
No play in the pulley?
No leakage of oil or water?
No clogging of the drain hole?
If any abnormality is found, describe it here
Sign off on the water pump check
250 Hourly Bulldozer Maintenance
LUBRICATING
NOTICE
If dirt or sand is found sticking due to work in the soft ground, carry out greasing every 10 hours of operation.
1. Lower the blde to the ground, then stop the engine.
2. Using a grease pump, pump in grease through the grease fittings shown by arrows.
3. After greasing, wipe off any old grease that was pushed out.
q D39EX,PX
(1) Lift cylinder bottom pin (2 places)
(2) Lift cylinder head pin (2 places)
When Required Bulldozer Maintenance
CHECK, CLEAN AND REPLACE AIR CLEANER ELEMENT
WARNING
q If inspection, cleaning, or maintenance is carried out with the engine running, dirt will get into the engine and damage it. Always stop the engine before carrying out these operations.
q When using compressed air, there is danger that dirt may be blown around and cause serious injury.
Always use safety glasses, dust mask, and other protective equipment.
CHECKING
1. Open engine side cover on the left side of machine.
2. If the yellow piston at the display portion of dust indicator (1) becomes red (7.5 kPa), clean the element.
NOTICE
2000 Hourly Bulldozer Maintenance
CHANGE OIL IN HYDRAULIC TANK, REPLACE OIL FILTER CARTRIDGE AND CLEAN SUCTION STRAINER
WARNING
• The parts and oil are at high temperature after the engine is stopped, and may cause burns. Wait for the temperature to go down before starting the work.
• When removing the oil filler cap, turn it slowly to release the internal pressure, then remove it.
• Refill capacity: 44 liters
1. Lower the blade to the ground securely, stop the engine and slowly turn the cap of oil filler (F) to release the internal pressure. Then, remove the cap.
2. Remove the cover (1) at the bottom of the hydraulic tank.
3. Place a container to receive drained oil on the track under the drain hole.
4. Loosen drain valve (2) at lower side of hydraulic tank to drain the oil, then tighten valve (2) again.
Access the parts list for your equipment in MaintainX.
D39Ex Power Angle Power Tilt Dozer End Bit (Left And Right)
11G-71-31170
Engine Oil Filter Cartridge
6733-51-5141
Fuel Filter Cartridge
6732-71-6111
D39Ex Power Angle Power Tilt Dozer Cutting Edge 21.9kg
12F-70-31281
Fresh Filter
14X-911-7750
D39Ex Power Angle Power Tilt Dozer End Bit (Left And Right)
11G-71-31170
Engine Oil Filter Cartridge
6733-51-5141
Fuel Filter Cartridge
6732-71-6111
D39Ex Power Angle Power Tilt Dozer Cutting Edge 21.9kg
12F-70-31281
Fresh Filter
14X-911-7750
D39Ex Power Angle Power Tilt Dozer End Bit (Left And Right)
11G-71-31170
Engine Oil Filter Cartridge
6733-51-5141
Fuel Filter Cartridge
6732-71-6111
D39Ex Power Angle Power Tilt Dozer Cutting Edge 21.9kg
12F-70-31281
Fresh Filter
14X-911-7750
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