PREVOST GKN AXLES LIMITED KIRKSTALL DIVISION, Руководство по обслуживанию

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Section 16: SUSPENSION
16-11
8.2 Maintenance
The height control valve requires no periodic
maintenance. Height control valve linkage oper-
ates on rubber bushings and no lubrication should
be attempted at this point.
8.2.1 Removal and Installation
Before disconnecting any height control valve air
lines, securely support the vehicle by its jacking
points on the body, and place safety support
underneath body. Refer to paragraph "16. Vehicle
Jacking Points" in Section 18, "Body".
Note:
The XL-40 coach battery main
disconnect switch door gives access to the
rear right height control valve.
FIGURE 13: HEIGHT CONTROL VALVE
16030
1. To gain access to a rear height control valve,
the corresponding wheel and mudguard can
be removed.
2. Exhaust air from air system by opening the
drain cock of each air reservoir. Remove
height control valve.
3. Disconnect overtravel lever from link and pull
down lever to exhaust remaining air from air
springs.
4. Disconnect air supply and delivery lines from
the height control valve. Cover ends of the
lines with tape to prevent the entry of foreign
matter (Fig. 11).
5. Remove the two nuts retaining the height con-
trol valve to the mounting bracket, then re-
move valve assembly (Fig. 13).
Reverse removal procedure to replace height
control valve. After installation, check for leakage
using a soap and water solution.
8.2.2 Air Leakage Test
Note:
The following procedure applies when
valve assembly has been removed from vehi-
cle.
1. Remove the height control valve from vehicle,
and clean thoroughly the exterior of valve as-
sembly.
2. Connect air pressure line to air inlet port, then
allow air pressure build-up (70- 100 psi (480 -
690 kPa)).
3. Dip the valve assembly in a container of water,
and watch for air bubbles when the overtravel
lever is in the center position. No air should
escape from any point of the valve assembly.
4. If bubbles appear from the air spring port, this
is an indication that the air inlet valve assembly
is defective and must be replaced.
5. Remove air pressure line from air inlet fitting
and connect it to the air spring port. If bubbles
appear at the air inlet check valve port, this is
an indication that check valve unit is defective
and must be replaced.
6. If bubbles appear at the exhaust port, this is an
indication that the exhaust valve assembly is
defective and must be replaced.
7. If bubbles appear around edge of valve cover
plate, the cover plate gasket must be replaced.
8. If no leaks are found, remove valve assembly
from water, then with air pressure still con-
nected to the air spring port, actuate overtravel
lever to remove any excess water which may
have entered exhaust valve chamber. Remove
air line, connect it to the air inlet port, and re-
peat operation to remove water from the air
inlet valve chamber.