PUMP 8W4027 - Caterpillar

Ensure that the engine is stopped before any servicing or repair is performed.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Cat Dealer Service Tool Catalog" or refer to Special Publication, PECJ0003, "Cat Shop Supplies and Tools Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.Dispose of all fluids according to local regulations and mandates.
The screen in the diesel exhaust fluid tank filler assembly will need to be cleaned if contaminated. Replace the screen if the screen cannot be cleaned. Also, replace the screen if the screen is damaged.
Illustration 1 g03701976
DEF filler assembly components
(1) DEF filler cap
(2) Retaining screws
(3) Cap adapter
Remove DEF filler cap (1).
Remove four socket head retaining screws (2) from within cap adapter (3). Do not remove the six smaller screws that are also present within the cap adapter.
Illustration 2 g03701992
Additional DEF filler assembly components
(3) Cap adapter
(4) Screen
(5) Hose adapter
Remove cap adapter (3) and screen (4) from hose adapter (5).
Wash all components that have been removed in clean water.
Compressed air may be used to clean the screen after first washing the screen in clean water. Use caution to avoid damage to the screen. If dirt and debris cannot be removed, or the screen is damaged, replace the screen.
Clean hose adapter (5) and the area around the hose adapter.
Install the screen in the hose adapter.
Install cap adapter (3) on the hose adapter and secure with the retaining screws. Install the DEF filler cap.