Ok thanks. There are two Ts - one to the ip, transmission and I think it goes to the HVAC. It's a w126 and the locks have their own electric vacuum pump in the trunk.

The T nearer the front is the shutoff. I've plugged them all and I cannot build much vacuum when the booster is hooked up. I'll start by replacing the damaged valve. The booster does look like a pain. Thanks for the heads up.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles