The lock should function properly regardless of the state of the vaccum system. It is possible that if the actuator is jammed in precisesly the wrong position that it might interfere with the the function of the lock but I doubt it. I'm assuming since your installing the tumbler that you have the trunk open.. if so just disconnect the actuator from the lock. Since you've stated the vaccum system is toast anyway.

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'84 300CD Turbo 132k (Anthracite Grey) - WVO - My daily driver - Recently named coo-coo-coupe by my daughter.
'84 300D Turbo 240k (Anthracite Grey) - Garage Queen
'83 300D Turbo 220k (Orient Red) - WVO - Wifes daily driver

I'm not a certified mechanic, but I did stay at a HolidayInn Express last night.