I have a 1997 Blazer that I am troubleshooting multiple issues that appear to be vacuum related (HVAC Controls, 4WD). And the vacuum hoses appear to be original and are just about disintegrating, to the point I can't read the dimensions on all of them. The one I could see was 5/32. What other sizes will I need if I want to replace all of the vacuum hoses in the system? And about how many feet of each size?

 

So even after talking to a GM tech and calling the dealer parts department, the answer is unanimous. Nobody knows. You just have to take off the old hoses and match them up. Which is a pain because the closes auto parts store to me is 15 minutes away.

In any case, I got it done and used mostly 5/32 if anybody else is wondering.