Ford 2007 F-650 Owner's Manual page 107

Driving
Do not continue to operate the vehicle with a failure of one of
the systems. Take the vehicle to your dealer for service
immediately.
Air brake reservoir draining
Failure to drain air brake reservoirs can result in a reduction or
loss of braking ability due to fluid accumulation in the reservoir
and/or possible freeze-up during cold weather.
Drain all the air brake reservoirs
daily, completely to 0 psi/kPa, by
opening the draincock at the ends
of the tanks (where accessible.
Pull-chains are used when the
drains are undercab or otherwise
inaccessible). Close draincock after
complete draining. Air tanks
equipped with automatic moisture
ejector valves may also be drained
manually as required to maintain a
dry air system. Contact your dealer if you are unsure of the air reservoir
locations or the draining procedure.
Parking brake
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 R (Reverse) for vehicles
equipped with manual transmission, N (Neutral) for vehicles with
automatic transmission (except Allison 2200 transmission) or P (Park)
(Allison 2200 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 will greatly increase and the handling of the
vehicle will be adversely affected. Repairs should be made immediately
to an inoperative air brake system circuit.
106
2007 F-650/750 (f67)
Supplement
USA (fus)