Ford 2013 F-650 Owner's Manual page 211

210
Some parts such as air brake chamber diaphragm, air compressor and air
cleaner should be inspected periodically and replaced if considered
unserviceable.
Air dryer: Climactic conditions affect performance of desiccant or
after-cooler type air dryers. Maintenance schedules must be established
for each specific operation.
The use of an air dryer on a vehicle does not eliminate the need to
periodically drain the air reservoirs.
Desiccant air dryer: Inspect for moisture in the air system by opening
reservoirs, draincocks or valves and checking for presence of water. The
presence of small amounts of water due to condensation is normal and
should not be considered as an indication that the dryer is not
functioning properly.
The desiccant cartridge should be replaced or rebuilt when it has been
determined that the desiccant is contaminated and does not have
adequate water absorption capacity. The desiccant change interval may
vary. It is generally recommended that the desiccant be replaced every
12 months (yearly). If experience has shown that extended or shortened
life has resulted for a particular installation, then the yearly interval can
be increased or decreased accordingly.
dry air system. Contact your dealer if you are unsure of the air reservoir
locations or the draining procedure.
WARNING: 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.
2013 F-650/750 (f67)
Owners Guide gf, 2nd Printing, March 2013
USA (fus)
Maintenance
Draining the air brake reservoir:
Completely drain all the air brake
reservoirs daily 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 the
draincock after draining. Air tanks
equipped with automatic moisture
ejector valves may also be drained
manually as required to maintain a