That rubber grommet in the booster may create an intermittent vacuum leak when driving. It would be a cheap part to replace and eliminate from the equation.
Napa has the grommet and check valve all for under $10 - https://www.napaonline.com/p/UBP89000?vehicleAddPDP=true
If you pick one up, you might have to use a little vaseline or WD40 to get the grommet installed.
Napa has the grommet and check valve all for under $10 - https://www.napaonline.com/p/UBP89000?vehicleAddPDP=true
If you pick one up, you might have to use a little vaseline or WD40 to get the grommet installed.