POST AS 9V9374 - Caterpillar

Always replace the secondary filter element. Never attempt to reuse the element by cleaning.The secondary filter element should be replaced at the time the primary element is serviced for the third time.
The filter should be kept in service for no longer than one year.
Always leave the secondary filter element in place while you clean the air cleaner housing.
Open the engine access door.
Remove the air cleaner housing cover.
Remove the primary filter element. Refer to Operation and Maintenance Manual, "Engine Air Filter Primary Element - Clean/Replace".
Illustration 1 g00470240
Remove the secondary filter element. Pull out in order to remove the element.
Cover the air inlet opening. Clean the inside of the air cleaner housing.
Install a new secondary filter element. Push the element firmly in order to properly seat the element. Write the date on the element.
Install the primary filter element and the air cleaner housing cover. Tighten the bolts for the air cleaner housing cover finger tight. Do not use a tool to tighten the bolts for the air cleaner housing cover.
Close the engine access door.