I've searched this site and have seen diagrams of the vacuum lines for NA Volvo 850's but no step-by-step guides to replacing them (ie to make sure I've found and replaced ALL of them as needed). Anyone know of such a thing?

I had a few of the vacuum lines replaced by a mechanic and since then I no longer get the suction sound when I remove the gas cap. He said he smoke tested it and found no leak. Is this even related?

Also, I'm planning to replace the fuel filter. Are there any lines down there that could be the culprit for the lack of suction that could/should be replaced?

Thanks a lot!

 

There shouldn't be suction on the tank. Usually you have expansion noise from the vapor heating up and causing pressure on the tank. Suction would make it hard to get the fuel cap off.

If you do not have vacuum leaks, leave it alone. No need to mess with something that is working fine. If you are board, go volunteer time down at the rice depot or somewhere.