Cummins/Onan — Removing and Installing the Fuel Filter
Maintenance · Fuel system
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKA, Cummins/Onan HDKAJ, Cummins/Onan HDKAK
Before you start
- Diesel fuel is combustible and can cause severe personal injury or death. Do not smoke. Keep flames, sparks and ignition sources away.
Procedure
- Wipe dirt off fuel fittings; open maintenance access door.
- Disconnect the two fittings at the filter and remove mounting nut.
- Use a wrench on the filter fitting and flare nut together.
- Rotate new filter half a turn on its stud if fittings interfere with bracket.
- Connect fuel fittings by hand before tightening filter mounting nut; tighten one flat past seating.
- Close access door; prime fuel system by holding control switch in Stop at least 1 minute.
Tools required
- Flare nut wrenches Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Fuel fittings at fuel filter: one flat passed finger tight
- Prime by holding control switch in Stop position at least 1 minute
Full service-parts list: Cummins/Onan HDKA →, Cummins/Onan HDKAJ →, Cummins/Onan HDKAK →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.