C 30 1 Ton Pickup 2WD V8-454 7.4L VIN W 4-bbl (1983)
Cruise Control Servo: Testing and Inspection
1.
Disconnect vacuum hose from servo and apply approximately 14 inches of vacuum to servo using a suitable pump with an integral gauge.
2.
If servo loses more than 5 inches of vacuum in 1 minute, servo is defective. Connecting vacuum hoses can be checked using a similar test
procedure.