Ford 2013 F-650 Owner's Manual page 162

Loosen the jam nut (A) and un-thread the adjustment rod (B) from the
chamber to reduce tension on the cable (C). Continue to un-thread the
adjustment rod all the way and remove it from the chamber. The nut and
shaft are metric.
Air Brakes
WARNING: Do not use the gearshift selector in place of the
parking brake; unexpected and possible sudden vehicle
movement may occur if these precautions are not taken. Always set the
parking brake fully AND make sure the gearshift selector is in position
R for vehicles equipped with manual transmission or position N (except
Allison 2200 transmission) or P (Allison 2200 transmission) for vehicles
with automatic transmission.
If the service brakes should fail to operate while the vehicle is in motion,
you can make an emergency stop with the parking brake. Since the
parking brake only applies stopping power to the rear wheels, the
vehicle's stopping distance greatly increases and the handling of the
vehicle is adversely affected. Repairs should be made immediately to an
inoperative air brake system circuit.
WARNING: This control is used for parking only. Do not leave
the vehicle unattended after setting the parking brake without
placing the transmission inposition R for vehicles equipped with manual
transmission or position N (except Allison 2200 transmission) or P
(Allison 2200 transmission) for vehicles with automatic transmission.
Use of wheel chocks is also recommended in hilly or off-road usage.
2013 F-650/750 (f67)
Owners Guide gf, 2nd Printing, March 2013
USA (fus)
Brakes
C
A
B
161