Engine
77
The pressure relief valve automatically relieves excess tank pressure in the event of an accident or fire,
thus preventing the tank from rupturing. The optional fuel sending unit sends a modulated electrical
signal to the fuel gauge and indicates the fuel level.
The level control valve, whistle, and pressure relief valve are mounted on the fill neck and are accessible
through the fuel fill door. These components cannot be serviced without first removing the fuel tank. See
the section on fuel tank removal in this chapter.
Level Control Valve Replacement
The level control valve should be replaced if it does not perform satisfactorily. After the fuel tank has
been removed from its mounting, proceed as follows:
1. Remove the whistle valve from the level control valve.
2. Remove screws securing the valve to the fuel tank.
3. Remove the valve assembly and gasket.
4. Clean old gasket material from the level control valve mounting surface on the fuel tank.
5. Position a new level control valve gasket and level control valve on the fuel tank.
6. Install mounting screws and tighten securely.
7. The whistle valve is threaded into the level control valve. It can be cleaned in a suitable solvent
type cleaner and the operating spring can be replaced as required.
8. Thread the whistle valve into the level control valve and tighten securely.
Pressure Relief Valve Replacement
The pressure relief valve should be replaced with a new unit if it does not perform satisfactorily.
1. Remove screws securing the pressure relief valve to the fuel tank.
2. Remove the valve and gasket from the fuel tank.
3. Clean old gasket material from the valve mounting surface on the fuel tank.
4.
Position a new gasket and pressure relief valve on the fuel tank. Install mounting screws and
tighten securely.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...