Chevrolet Silverado / GMC Sierra. Service manual — part 598

Fig. 75: View Of Flare Nut Socket
Courtesy of GENERAL MOTORS CORP.

The torque of a fuel line fitting is critical to prevent fuel leaks in a high pressure direct injection
fuel system. The preferred method is through the use of a flare nut socket. With the use of a flare
nut socket, the torque wrench can be set to the listed torque specification. Refer to Fastener
Tightening Specifications .

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

If a crows foot is used to torque the fuel lines, then special attention to the position of the crows
foot in relation to the torque wrench is required.

Fig. 76: View Of Crows Foot (90 Degrees)
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

If the crows foot is kept perpendicular (90 degrees) to the torque wrench during the entire
tightening procedure, then the torque wrench can be set to the listed torque specification.
Refer to Fastener Tightening Specifications .

Fig. 77: View Of Crows Foot (Straight)
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

If the crows foot is positioned straight with the torque wrench, then the torque setting needs
to be corrected to compensate for the increased leverage.

If the crows foot is held at any position other than 90 degrees or inline to the wrench, more
complex corrections of the torque setting are required, and therefore, positioning the crows
foot in this manner is not recommended.

If it is necessary to position a crows foot in line with the torque wrench, the procedure for
adjusting the torque specification is as follows:

Fig. 78: Measuring Center Of Crows Foot Wrench End To Center Of Square Drive

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado