Komatsu D31EX-21, Operation & Maintenance Manual, Page: 196 / 256

PERIODIC REPLACEMENT OF SAFETY CRITICAL PARTS
MAINTENANCE
4-16
PERIODIC REPLACEMENT OF SAFETY CRITICAL PARTS 4
For using the machine safely for an extended period of time, you must periodically replace the safety critical and
fire prevention-related parts listed in the table of important parts.
Material quality of these parts can change as time passes and they are likely to wear out or deteriorate. However,
it is difficult to determine the extent of wear or deterioration at the time of periodic maintenance. Hence, it is
required to replace them with new ones regardless of their condition after a certain period of usage. This is impor-
tant to ensure that these parts maintain their full performance at all times.
Furthermore, should anything abnormal be found on any of these parts, replace it with a new one even if the peri-
odic replacement time for the part has not yet arrived.
If any of the hose clamps show deterioration like deformation or cracking, replace the clamps at the same time as
the hoses.
Also perform the following checks with hydraulic hoses which need to be replaced periodically. Tighten all loose
clamps and replace defective hoses, as required.
When replacing hoses, always replace O-rings, gaskets, and other such parts at the same time.
Have your Komatsu distributor replace the critical parts.
SAFETY CRITICAL PARTS 4
No. Safety critical parts for periodic replacemen Q'tyt Replacement interval
1 Fuel hose (fuel tank - water separator) 1
Every 2 years or 4000
hours, whichever comes
sooner
2 Fuel hose (water separator - fuel feed pump) 1
3 Fuel return hose (injection pump - fuel tank) 1
4 Fuel return hose (injection nozzle - fuel tank) 1
5 Fuel drain hose (fuel tank - drain valve) 1
6 Case, plug and O-ring of water separator 1
7 Turbocharger lubrication hose 1
8 Hose (PPC circuit) [hydraulic tank - block (center portion under floor)] 1
9
Hose [4-spool solenoid valve (left side under floor) - block (center por-
tion under floor)]
1
10 Hose (L.H travel motor brake port - R.H travel motor brake port) 1
11 Hose (L.H travel motor brake port - towing valve) 1
12 Hose (towing valve - parking brake control valve) 1
13 Hose [L.H. travel motor FORWARD port (MA) - HST pump (PA1)] 1
14 Hose [L.H. travel motor BACKWARD port (MB) - HST pump (PB1)] 1
15 Hose [R.H. travel motor FORWARD port (MA) - HST pump (PB2)] 1
16 Hose [R.H. travel motor BACKWARD port (MB) - HST pump (PA2)] 2
17 Suction hose [hydraulic tank - charge pump (HSS pump)] 2
18 Suction hose (divider tube for hydraulic tank - hydraulic pump 2
19 Hose (hydraulic pump - main control valve) 2
20 Seat belt 1 Every 3 years