If you look in the books, Mercedes call this a PARKING brake...I'd set it when parked. Just don't forget to take it off or you will ruin rotors and shoes.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
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