rootney

I just installed an AC delete cover after removing the AC evap. on my 72 Cutlass.
It retains the heater and defrost functions. My question is, can I also remove the vacuum can on the firewall?

Fun71

I think without it you won't have control of which vents the air comes out of. It will blow through the floor (heater) only.

Lady72nRob71

Losing the can will cause the air to fade to the floor upon low vacuum actions, like hill climbing or acceleration. Under high vacuum, like idle or cruise, it will act normally.
You would not want the defroster to quit working when going up a hill, so I would leave it. Now if defrost is not needed in your area, try bypassing it and see how you like it. Keep the can just in case you want to use it again.
The heater only cars controlled the air doors by cables rather than vacuum, so they did not need the vac cans.

rootney

I guess I was mislead. I thought non-AC cars didn't have the can.

rcorrigan5

My '68 without A/C has no vacuum canisters on the firewall. The flow of air is directed mechanically by the levers on the heater control panel.

Is your canister hooked up to something on both ends? If so, just bypass it and see what happens. I don't think there will be any difference.

Randy C.

Lady72nRob71

You are correct - no can since those were all cable-controlled. AC models used vacuum to control the air doors. If you replaced the control set with a cable-driven set from a heat-only car, then the can would not be needed.

rootney

Got it.
Thanks.