Komatsu PC138USLC Operation & Maintenance Manual page 302

MAINTENANCE
Method Using Block
Select a firm flat place.
Put strong blocks under the undercarriage to stabilize the machine and be extremely careful when carrying out the operation.
1. Raise the chassis with the boom and arm.
When doing this, operate the levers slowly.
2. Insert a block securely between the ground surface and the
raised track and make sure that the machine is stable.
3. Raise the boom slowly and lower the machine.
When doing this, check that the machine is always stable.
WARNING
MAINTENANCE PROCEDURE
4 - 41