What tool or how can I reach the vacuum line from the brake booster?

I have a 2002 Volvo S80 and both catalytic converters are gone bad Firestone told me it was the senors and I was taking it to Volvo dealership to get the sensors fixed and they told me it's the two converters - codes 4801 and 4901 came up on hand held reader -I'm so sad the repairs cost more than what the car is worth.