I’m doing an SS dash conversion on my 70 Malibu. Anyway, the Malibu dash is removed now and I want to make sure the vents and such are going to all work correctly before I install the new SS dash- AC car.
Someone in the past has removed or at least loosened the interior box that mounts to the firewall because the 2 vacuum lines that run through the firewall were looped under the lip and pinched off completely. That part has been remedied.
The vacuum canister/ball had been removed from the (under the hood) half of the box and this has also been replaced.
My questions are:
There are 2 lines, a black line with a white trace and a solid black line that run through the firewall. What goes to what? There are also 2 ports on the vacuum ball, I’m assuming one of the lines goes to that and something somewhere needs to go to the intake or carb to actually get vacuum to this whole mess…..
This is the hole in the firewall
http://members.cox.net/darrenb55/images/dsc02757.jpg

These are the lines in question- pulled back through to the inside for testing...
http://members.cox.net/darrenb55/images/dsc02758.jpg

In the engine bay, the solid black hose connects to the smaller port on the vacuum can. The black hose with the white trace connects to the heater hose control valve on the passenger fender. The larger port on the vacuum canister connects to constant manifold vacuum at the intake manifold tee between the carb and distributor; this manifold port also supplies vacuum to power brakes.

Inside the car, those same two vacuum lines loop up to the vacuum line control tee in the upper dash. I can't see exactly where they connect, but here is a photo on my connections:

Vacuum controls: http://i58.photobucket.com/albums/g244/f1970chevelle/Chevelle/vacuum-controls.jpg

Vacuum canister:
http://i58.photobucket.com/albums/g244/f1970chevelle/Chevelle/vacuum-can.jpg

I recently pinched those same two hoses when I replaced the heater core. They are in a difficult-to-reach location.

Perfect!! Thank you, just one more question, I’m not sure what (or where) the “
heater hose control valve on the passenger fender” is?

Is this in the engine bay on the inter fender? I noticed there is a silver diaphragm pod under the cowl area on the passenger side but it appears to have a line already running to it (not sure what that’s for either)

I think I found it, where the heater hose runs in and out correct?

re-read your post, good to go now, thank you for the great advice!!

Just sharing my frustrations…. So I get all the vacuum lines all hooked up and fire up the car (the dash is still off). I’m moving the heater/air controls and the dampener doors are all opening and closing and I’m happy!! :hurray:

Because there was no vacuum line to the heater control on the right inter fender my guess is there was no antifreeze getting into the heater core…. Now that it’s all hooked up correctly and the fluid is flowing it seems I have a hole in the heater core and the fluid just flows right out onto the floor….

O-well at least I haven’t replaced the carpet yet…..:angry: