Vario814D handbrake?

Cab anyone please tell me why my vario814 D dumps all the air the second the handbrake is released.
Someone trIed to move it by plunging there airline's on to it when engine was not running.
Is it something they have done?
It's a Mercedes benz vario814D
Reg S679ASX
Can anyone help
Mick, December 2022


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