Yeah, I had hell with my vacuum locks. I had so many leaks I stopped looking. I ended up plugging off the door lock portion and installed an electric set up for all doors and trunk. I bought a kit off of Ebay ($40) with a couple of extra solinoids for gas cap and trunk. Now I can unlock the doors, trunk and gas cap with a remote key fob kind of like an alarm. I like the new system so much I'm going to install a kit in my VW Golf next.
No, it's not original, but it works mighty fine.

Just a thought in case you get tired of the vacuum set up.