GILLIG LOW FLOOR, Руководство по обслуживанию

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46
Suspension
RIDE HEIGHT ADJUSTMENT
The air suspension height control valves (also known as “leveling valves”) automatically control the air
pressure in the air springs to maintain the proper ride height. As the vehicle is loaded, the air springs will
compress slightly. The height control valve actuating arm will be moved up from the neutral position to
the fill position. This will allow air from the air tanks to flow into the air springs, increasing the pressure
in the springs, bringing the air spring back to the proper height. When the vehicle is unloaded, the air
springs will slightly increase in length and the height control valve actuating arm will be moved from the
neutral position to the exhaust position. This will exhaust some of the air in the air spring until enough
air has been exhausted to bring the air spring back to the proper height. The proper air spring height
is important to allow for proper suspension travel and to maintain the proper driveline angles. Out-of-
adjustment air spring heights can cause the bus to lean, not allow for full suspension travel leading to
bottoming or topping out of the suspension, or cause improper driveline angles leading to driveline life
or vibration problems. The height control valves do not “level” the bus. They only control the air spring
height.
The front suspension has one height control valve and the rear has two. The two rear suspension height
control valves keep the bus level to the road (controls leaning) while the single front valve only main-
tains the proper air spring height at the front suspension air springs.
To check and adjust the air spring height:
1. The air system must have at least 80 psi in the accessory air tank. Before adjusting the air spring
height, run the engine until the air gauge in the dash reads at least 110 psi or apply shop air until
the gauge reads at least 100 psi.
Never get underneath any part of the coach unless its weight is fully
supported by jack stands or blocks on the frame. Never put yourself in
a position where a change in air spring pressure could cause the coach to
crush or pinch you. The Low Floor bus has very little ground clearance
with the air springs exhausted!
2. Either work from a pit or install jacks or blocks under the frame at the front and rear of the bus.
Refer to the “Jacking” section of the General Information chapter for jacking points. Do not jack
the bus up; just install the jacks or blocks up to the frame to prevent the bus from dropping and
causing injury or damage when the height control valves are adjusted. If the air spring heights are
too large before adjusting, the bus may lower down onto the jacks/blocks under the frame. If this
happens, raise the bus and set the jacks/blocks lower so the bus frame will clear the jacks/blocks
when the springs are set correctly.
3. First check the rough adjustment of the front air springs (Figure 5-2). The front air spring height
should be 9". If the front air spring height is 8.5" to 9.5", go to Step 4 and set the rear suspension
air spring height. If not within this range, loosen the clamp holding the link end and push the
link up to raise the air spring height or down to lower the air spring height. Move the link very
slowly; there will be a delay between the time when the link is moved, to when the air spring
height will start to change. When the proper air spring height is reached, center the valve in the
neutral position and tighten the link end clamp. To hold the valve in the neutral position while