PREVOST LE MIRAGE XLII, Руководство по обслуживанию

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Section 16: SUSPENSION
PA1553
30
10.1 LOADING POSITION
As the load increases and lowers the vehicle
body, the overtravel lever commands the height
control valve to add air to air springs.
10.2 NEUTRAL POSITION
When vehicle body reaches the normal ride
height, the height control valve overtravel lever
reaches the "neutral" position and keeps both
the supply and exhaust ports closed to ensure
normal ride height is maintained. This condition
remains static until the vehicle load is altered.
10.3 UNLOADING POSITION
As the load decreases and raises the vehicle
body, the overtravel lever commands the height
control valve to release air from air springs.
10.4 MAINTENANCE
The height control valve requires no periodic
maintenance. Height control valve linkage
operates on rubber bushings and no lubrication
should be attempted at this location. Inspect the
valve for loose joints, air leaks and worn
bushings.
10.5 REMOVAL AND INSTALLATION
Before disconnecting a height control valve air
line, securely support the vehicle by its jacking
points on the body, and place safety supports
underneath body. Refer to paragraph
"16.
Vehicle Jacking Points" in Section 18, "Body" .
1. Exhaust air from air system by opening all
air tank drain cocks. Remove height control
valves.
2. Disconnect overtravel lever from link and
pull down lever to exhaust remaining air
from air springs.
3. Disconnect air supply and delivery lines
from the height control valve. Cover line
ends with tape to prevent entry of foreign
matter.
4. Remove the nuts retaining the height control
valve to the mounting bracket, then remove
valve assembly.
Reverse removal procedure to replace height
control valve. After installation, check for
leakage using a soap and water solution.
11. "LEVEL-LOW" LEVELING SYSTEM
Bus shells are equipped with "LEVEL-LOW"
leveling system. The purpose of the "LEVEL-
LOW" is to adjust suspension in three separate
points (front, rear right and rear left air springs)
in order to level vehicle body. Three height
control valves, automatically control air pressure
in the three separate points (air springs) and
maintains a constant vehicle height regardless
of load, or load distribution. The control solenoid
valve supplies air to the five way three-position
air control valve, which bypasses the height
control valve, and opens a passage to allow the
air control and exhaust valve to release/supply
air from airs springs. To improve road comfort,
an expansion air tank is installed in series with
each air spring.
In addition to the above suspension components
the system also includes: sway bar, upper and
lower A-arms, rods and shock absorbers (Fig.
1).
NOTE
Only for preliminary adjustment, refer to figure
21. Torque rod length must be fixed to
21 17/64" (540 mm) and relay rod to 23 19/64"
(592 mm).
CAUTION
Parts must be replaced by ones with the same
part numbers or with equivalent parts, if
replacement becomes necessary. Do not use
parts of lesser quality or substitute design.
Torque values must be used as specified
during reassembly to assure proper retention
of these parts.
The purpose of the "level-low" leveling system is
to adjust suspension in three separate points
(front, rear right and rear left) in order to level
vehicle body. This system can be put into
service when the ignition key is turned to the
"ON" position, and must be used only when the
parking brake is applied. The "level-low" warning
light on the dashboard indicates that the selector
switch is not in the
"OFF" position. Level low
system controls are located on L.H. side control
panel.