Volvo VNL 780 Operator's Manual page 376

366 OPERATION
Wait about 30 seconds for the air springs to deflate.
With the suspension lowered, pull clear of the trailer and immediately select the "RIDE"
position (press the top part of the switch in) on the suspension control. This restores the
suspension to operating height.
CAUTION
The vehicle must never be driven with
the air springs deflated. Damage to air
suspension parts will occur if springs are
not inflated properly.
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