Air Horn Replacement

Air Horn Replacement

Removal Procedure

1. Discharge the air pressure from the air brake system. Refer to Pressure Protection Valve Replacement in Air Brakes.




2. Remove the lanyard bolt from the inner roof panel.




3. Remove the left rear quarter trim panel (models with headliner). Refer to Headlining Trim Panel Replacement (Regular Roof) Service and Repair in Interior Trim.
4. Remove the air horn opening trim cover, if used.
5. Remove the air horn air tube from the air horn valve.
Tape the air horn air tube to the roof in order to help prevent the air line from recoiling back into the roof panel.




6. For flat roof, remove the air horn front mounting bracket.
7. Remove the air horn mounting bolts.
8. Remove the air horn assembly from the roof.




9. For a raised roof, remove the air horn front mounting bracket.
10. Remove the air horn mounting bolts.
11. Remove the air horn assembly from the roof.
12. Disconnect the air horn tube from the air horns.

Installation Procedure

1. Connect the air horn tube to the air horns.
2. Route the lanyard through the roof into the cab.
3. Install the air horn assembly to the roof.




4. For flat roof, install the air horn front mounting bracket.

Notice: Refer to Fastener Notice in Cautions and Notices.

5. Install the air horn mounting bolts.

Tighten the air horn mounting bolt to 9 Nm (80 lb in).




6. For a raised roof, install the air horn front mounting bracket.
7. Connect the air horn tube to the air horns.
8. Install the air horn mounting bolts.

Tighten the air horn mounting bolt to 9 Nm (80 lb in).

9. Install the air horn air tube to the air horn valve.
10. Install the air horn opening trim cover, if used.




11. For models with headliner, install the left rear quarter trim panel. Refer to Headlining Trim Panel Replacement (Regular Roof) Service and Repair in Interior Trim.




12. Install the lanyard bolt to the inner roof panel.

Tighten the lanyard bolt to 2 Nm (18 lb in).