Step 1. Remove the cap.
Step 2. Remove the two circlips & mesh basket if still there.
Step 3. Remove the circlip supplied off the diesel Guard unit.
Step 4. Close the circlip provided so that it will fit down the filler neck. Tie a piece of cotton around the circlip and attach to your finger in case you drop it.
Step 5. Push the circlip into either of the two grooves.
Step 6. Slide the wedge provided into the gap in the circlip. Tap the wedge until the top of the wedge is almost level with the top of the filler neck.
Step 7. Open the security legs with a screwdriver.
Step 8. Pull out the slide, lock into place. Line the wedge up with the recess in the top plate and push quickly into place. See fitted Diesel Guard unit below.
Step 9: Installed.