Komatsu D31EX-21, Operation & Maintenance Manual, Page: 226 / 256

SERVICE PROCEDURE
MAINTENANCE
4-46
METHOD OF USING AUTOMATIC AIR BLEED MECHANISM
(If equipped)
WARNING
The engine will start, so check carefully that the area around the engine is safe before cranking it.
It is possible to bleed the air from the fuel circuit simply by rotating the starting motor with the starting switch. Bleed
the air as follows;
1. After replacing the filter cartridge, the engine is started, so follow the procedure in “OPERATION AND CHECK
BEFORE STARTING ENGINE (3-75)“.
2. Set the fuel control lever to the midrange speed position.
3. Set the parking lever of the steering, directional and gear
shift lever to the LOCK position.
4. Turn the key in the starting switch to START and hold it
there for 20 seconds.
When this is done, the starting motor will be actuated for
approx. 2 seconds and then will stop, but the electric air
bleed pump continues to be actuated and bleeds the air.
Keep the starting switch key at the START position for 20
seconds, regardless of whether the engine turns or not.
Low idling
Free
Lock