Usage:
D25C, D250B, D30C, D300B, D35C, D35HP, D350C, D400 Trucks
Description of Change: A new pressure switch is used in the suspension inhibit circuit. The switch prevents the suspension from self-leveling when the services brakes are applied. The new pressure switch provides a longer service life than the former pressure switch. The pressure switch is located in one of the service brake valve ports.
Adaptable To: The new 9X3269 Pressure Switch Assembly replaces the former 6U4086 Pressure Switch. The new pressure switch assembly is in effect as shown in Chart A.
The new pressure switch assembly and additional components shown in Chart B are adaptable to the trucks shown in Chart C. There is one of each component.
Procedure To Install Pressure Switch Assembly On Earlier Trucks
1. Remove the former 6U4086 Pressure Switch.
2. Assemble pressure switch assembly (1), O-ring seal (3), adapter (2) to elbow (4) as shown in the illustration. Install this assembly where the former pressure switch was removed.
Location of components.
3. Cut the two terminals off the wires that were removed from the former pressure switch.
4. Crimp (install) pin (6) to the brown wire.
5. Crimp (install) socket (8) to the white/purple wire.
6. Install pin (6) into Hole 1 of receptacle (5).
7. Install socket (8) into Hole 3 of receptacle (5).
8. Install plug (7) into Hole 2 of receptacle (5).
9. Install the receptacle assembly to the housing of pressure switch assembly (1).
10. To verify correct operation of the system, fully lower the front suspension to the service position. See Service Manual or Operation and Maintenance Manual for correct procedure. Then, start the engine with the service brakes applied and the parking brake engaged. Wait for one minute then release the service brake pedal. The suspension MUST NOT self-level when the service brake pedal is applied. The suspension MUST self-level when the service brake pedal is released.