

The Komatsu Bulldozer D39PX-21 is a robust and versatile piece of heavy machinery designed for various earthmoving tasks. Known for its reliability and efficiency, this bulldozer excels in construction and landscaping applications, making it an essential asset for any industrial operation.
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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 Bulldozer D39PX-21
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1000 Hourly Bulldozer Maintenance
CHANGE OIL IN FINAL DRIVE CASE
WARNING: The oil is at high temperature immediately after the machine has been operated. Wait for the oil to cool down before starting the operation. If there is still pressure remaining inside the case, the oil or plug may fly out. Loosen the plug slowly to release the pressure.
Set the TOP mark at the top, with the UP mark and plug (P) perpendicular to the ground surface.
Set a container under plug (P) to catch the oil.
Remove plugs (P) and (F) with the handle and drain the oil.
Check the O-rings in the plugs for damage. If necessary, replace with new ones.
Tighten plug (P).
Add oil through the hole of plug (F).
When oil begins to overflow from the plug (F) hole, install plug (F).
2000 Hourly Bulldozer Maintenance
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.
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.
Remove the cover (1) at the bottom of the hydraulic tank.
Place a container to receive drained oil on the track under the drain hole.
Loosen drain valve (2) at lower side of hydraulic tank to drain the oil, then tighten valve (2) again.
For the cab specification machine, cancel lock (3) of the inspection cover at the right side at the rear of the machine, remove the bolts, then remove rear cover (4). Remove the washer tank.
For machines other than the cab specification machines, remove the bolts, then remove the cover at the right side at the rear of the machine and center cover (4) at the rear.
Using the filter wrench, turn filter cartridges (5) and (6) to the left and remove them.
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)
4000 Hourly Bulldozer Maintenance
Check water pump for any play in the pulley
Check water pump for any leakage of oil or water
Check water pump for any clogging of the drain hole
Report any abnormalities found
Sign off on the 4000 Hourly Bulldozer Maintenance
500 Hourly Bulldozer Maintenance
WARNING: Engine is at high temperature immediately after the machine has been operated. Wait for engine to cool down before replacing the filter. Do not bring fire or sparks near the fuel.
Prepare a filter wrench and a container to catch the fuel.
Set the container to catch the fuel under the filter cartridge.
Using a filter wrench, turn filter cartridge (1) counterclockwise to remove it.
Clean the filter holder, fill a new filter cartridge with clean fuel, coat the packing surface with engine oil, then install it to the filter holder.
When installing, tighten until the packing surface contacts the seal surface of the filter holder, then tighten it up 1/2 to 3/4 of a turn.
After completing the replacement of filter cartridge (1), bleed the air.
Bleed the air as follows.
WARNING: The engine will start, so check carefully that the area around the engine is safe before cranking it.
Access the parts list for your equipment in MaintainX.
Air Cleaner Element Assembly (Inner And Outer)
600-185-2500
Corrosion Resistor Cartridge (If Equipped)
600-411-1151
D39Px Power Angle Power Tilt Dozer (Narrow Blade) (Bolt)
02090-11055
D39Px Power Angle Power Tilt Dozer (Narrow Blade) Cutting Edge 13.0kg
11Y-72-12330
D39Px Power Angle Power Tilt Dozer (Narrow Blade) End Bit (Left And Right)
112-946-1510
Air Cleaner Element Assembly (Inner And Outer)
600-185-2500
Corrosion Resistor Cartridge (If Equipped)
600-411-1151
D39Px Power Angle Power Tilt Dozer (Narrow Blade) (Bolt)
02090-11055
D39Px Power Angle Power Tilt Dozer (Narrow Blade) Cutting Edge 13.0kg
11Y-72-12330
D39Px Power Angle Power Tilt Dozer (Narrow Blade) End Bit (Left And Right)
112-946-1510
Air Cleaner Element Assembly (Inner And Outer)
600-185-2500
Corrosion Resistor Cartridge (If Equipped)
600-411-1151
D39Px Power Angle Power Tilt Dozer (Narrow Blade) (Bolt)
02090-11055
D39Px Power Angle Power Tilt Dozer (Narrow Blade) Cutting Edge 13.0kg
11Y-72-12330
D39Px Power Angle Power Tilt Dozer (Narrow Blade) End Bit (Left And Right)
112-946-1510
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