I am trying to get my hvac system working in my 87 gta ls1 car. The first issue that I have is that I have a huge vaccuum leak at the vacuum selector switch on the left side of the control panel, the one that is attached to the hot /cold slider on the bottom. When it is all the way over on the cold side it doesn't leak but when I slide it into the hot zone it leaks like crazy. I tried a different one and I also tried the trick with the 8-32 screw and nylock nut. No luck with either of those. Does anyone have any ideas ?

 

Anyone know what this part is xalled or where I can find one