SECTION 12: BRAKE AND AIR SYSTEM
6
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
FIGURE 4: FRONT SERVICE COMPARTMENT
12210
These two air system emergency fill valves are
fitted with the same valve stems as standard
tires, and can be filled by any standard external
air supply line.
The rear air system emergency fill valve will
supply air for all systems (brakes, suspension
and accessories) while the front fill valve will
supply air for accessories only.
5.
ACCESSORY AIR FILTER
FIGURE 5: ACCESSORY AIR FILTER
Item
Description
1 FILTER
2
METAL BOWL W/ MANUAL DRAIN
3 PURGE
This filter is located inside the front service
compartment (Figure 4). Its main function
consists in filtering the air supplied to the
accessory air system, when connected to an
external supply line. Ensure filter is purged
whenever supplying the system with an external
air line and at least every 12,000 miles. To
purge, open drain valve (Figure 5), let the
moisture come out, then close the drain valve.
5.1
FILTER ELEMENT REPLACEMENT
Replace filter element whichever of the following
occurs first: every 100,000 miles (160 000 km),
every two years, or whenever differential
pressure exceeds 15 psi (105 kPa) between
filter inlet and outlet ports. Check condition of all
three O-rings for damage. Replace when
necessary (Figure 5).
5.2 CLEANING
Clean filter body and bowl with a warm water
and soap solution. Rinse thoroughly with clean
water. Blow dry with compressed air making
sure the air stream is moisture free and clean.
Pay particular attention to the internal passages.
Inspect all parts for damage and replace if
necessary.
6.
AIR GAUGES (PRIMARY, SECONDARY
AND ACCESSORY)
The air pressure gauges, located on the
dashboard (see
"Operator's Manual"
), are fed
from pressure transducers connected to the
DC-4 double check valve, located on the
pneumatic accessory panel in the front service
compartment.
The latter is connected to the air lines running
from the primary and secondary air tanks, as
shown on the pneumatic system diagram
provided in the technical publications box. The
accessory air gauge is connected to the
accessory air tank using the drain valve
connector. The vehicle should never be set in
motion until the buzzer alarm and warning lights
turn off, i.e. when air pressure registers at least
75 psi (517 kPa). Moreover, if pressure drops
below 75 psi (517 kPa), the
"Low air pressure"
warning lights will turn on, and the
"Low air
pressure"
buzzer will sound. Stop the vehicle
immediately, determine and correct the cause(s)
of pressure loss. Check the gauges regularly
with an accurate test gauge. Replace the gauge
with a new unit if there is a difference of 4 psi
(27 kPa) or more in the reading.
