Vac leak affecting brakes

[gumby6371]

As in my other posts I have the anti pollution fault regularly popping up due to a vac leak on the swirl actuator but I've noticed when the car is boosting properly that I lose braking performance sometimes which I'm also putting down to a vac leak.
I drove up the road at about 35 and stamped on the pedal, nose dipped sharply, ABS kicked in car stopped dead then pulled away and did it again no ABS and car gently slowed to a stop - my diagnosis vacuum leak (correct me if I'm wrong).

So my question is would a leaky actuator leak enough vacuum to affect the brakes in this way? I know the system is designed to prioritise the brakes.

Every time I've planned to change the actuator its tipped down with rain but I did wonder whether plugging the vac feed for the EV's and EGR at the reservoir and from the cylinder would be a good test?
Obviously I'd get warning lights on the dash but the brakes should then have max vacuum pressure?????

[steve_earwig]

Do they have some sort of vacuum reservoir? Aha!

1627 72 VACUUM RESERVE LONG 54X194 - UNTIL RPO 09820

Maybe the leak is small enough to allow the reservoir to fill (empty surely?) but it takes a wee while to refill (re-empty ) once the vacuum's been used, so using the brakes twice in quick succession makes the second time far less effective.

[Doggy]

They start life with a vacuum reservoir, (the coupe boys are tending to remove them nowadays to simplify the system - granted this goes hand-in-hand with removing 2-off egr valves and the air doser, so maybe you don't need it anymore, though I wouldn't fancy convincing an insurance company's engineer).

There are also a couple of vacuum restrictors, which, if I understand it correctly, are meant to ensure there will be enough vacuum for the brakes, even if you have a leak elsewhere in the system.