Couple questions about the hard vacuum lines which make up the PCV system. First, I am finding it darned near impossible to find them at parts stores, and all the Volvo shops are closed for the weekend, so Carquest said to just use rubber vacuum lines instead, is that an OK thing to do? And second, if I go that route, can I get a larger diameter line so that I no longer need the rubber elbow fitting, so that I can just fit the line straight to the oil trap?

 

That should work fine.
I haven't tried it but it should work.