I noticed my vacuum line under the battery tray that is connected to the sphere vacuum canister is very corroded. That line leads to the vacuum three-way valve. I know the the larger diameter line goes directly to the intake manifold. That line at the intake manifold is also showing cracking. My question is where does that third vacuum line go that comes of that
three-way valve? I can't see where it goes. Also, what is the correct part number for the sphere canister and three-way tee valve?

 

See this thread for some more info.

https://chevroletforum.com/forum/exp...-issue-117027/

 

thx !

 

THX ! I now believe that third vacuum line is very small diameter and appears to be plastic. I can see where it attaches in the
interior where a glove box would normally be. I ain't messing with that connection. The large diameter from the intake manifold
and the smaller line to the sphere canister are the only lines I'm going to mess with.

 

No problem. That plastic tubing can get brittle. It goes to the HVAC. If you pull back the carpet a bit on the passenger side you should be able to see them. Replacing it might not be too easy. I haven't messed with mine.

 

I have pulled the rug back some and I don't see any tubing.

 

Did the repair today. Pulled just the passenger seat which made removing the doghouse very easy. Removed the coolant reservoir and
battery to gain better access to the vacuum sphere. When I barely touched the line connected to the sphere the line just dropped off.
Very oxidized! Much worse than the 7/32 line but it was also bad. Oh !...Make sure to remove the lower dash panels on each side of the
doghouse. Both very easy to remove. Buttoned everything up and everything great ! All AC control directional functions work great. My
5.3L runs strong !

 

Glad you got it fixed. The rubber from this era sure doesn't last!

 

I think they were original lines. And they showed it !

 

I found that line to be bairly attached in my van as well.
That sure is a Ppour vacuum hose quality.
Shipped about a 1\4" off and reattached it.

On my 01 drive to work junker dodge, I made an auxiliary vac tank from an old propane cylinder and strapped it to the fender well.