OPERATOR'S MANUAL

Preventive Maintenance Air System
Model 330 PB1318 3/01 – 165 –
Air System Function Test
Scheduled maintenance should be performed on the Model
330 air system, as outlined in the Medium Duty Mainte-
nance Manual and Table 11. In addition, perform an Air Sys-
tem Function Test at least every 3 months or if there is any
indication of a potential problem.
Air Tanks
The front (secondary) service tank is underneath the cab, on
the driver’s side; the wet (supply) tank is underneath the front
service tank, behind the battery box; and the rear (primary)
service tank is attached to the left frame, just behind the cab.
The supply tank (or “wet” tank), must be drained on a daily
basis. Drain the supply tank by pulling the drain valve lan-
yard. Hold it open until the escaping air is free of water.
The two service tanks (or “dry” tanks), must be drained on a
weekly basis. Drain the two service tanks by opening the
drain valves. Turn valve handles counter-clockwise, and
leave open until the escaping air is free of water.
WARNING! If the supply and service tanks are
not drained at the recommended frequency,
water could enter the air lines and valves. This
could cause corrosion or blockage, which could
compromise the brake system safety and poten-
tially cause an injury accident.
Periodically: Clean filter screens ahead of the valves by
removing the screens and soaking them in solvent. Blow
them dry with pressurized air before reinstalling them.
Location of Air Tanks
FRONT
SECONDARY
(SERVICE) TANK
DRAIN VALVE
WET (SUPPLY)
TANK UNDER
REAR PRIMARY
(SERVICE) TANK
02602
FRONT SERVICE
TANK