F 250 4WD Super Duty V8-5.4L SOHC VIN L (1999)
Wheel Hub (Locking): Testing and Inspection
VACUUM LEAK TEST - WHEEL END
Special Tools
1. NOTE: Whenever the front wheel hub, axle shaft or the hub lock is removed and installed, the front wheel-end assemblies must be leak-checked
to ensure that the sealing surfaces are intact. Failure to do so can cause the loss of four-wheel drive operation and contamination of the vacuum
system.
Disconnect the wheel-end vacuum hose.
2. Connect the hand vacuum pump (part of Vacuum Tester) to the vacuum fitting on the wheel knuckle.
3. NOTE: The wheel-end assembly must not leak more than 0.50 in-Hg in 30 seconds. If the wheel-end leak rate exceeds the specification, refer to
Transfer Case Testing and Inspection under Transmission and Drivetrain.
Apply 15 in-Hg of vacuum to the wheel-end assembly and observe the reading for 30 seconds.
4. Repeat the leak testing procedure for the opposite wheel-end.
