Attempting to get the vacuum system correct and working. I have seen the vacuum diagrams on this site and another bird site.
Does the vacuum line for the rear vent/emergency brake release/neutral safety switch tee off the main vacuum supply line before or after the check valve? Does it make any difference about the size of the vaccum lines as long as you don't get to big or smaller? Where does the vacuum supply line for the heating/AC system go thru the firewall down low on the passenger side or by the right hand hood hinge?

The inside diameter of the hose should be the same. Of course this all that will fit. I did find that new vac hose has a much smaller O.D. My parts guy said that was because the new material is stronger and did not need all the material to maintain shape as the original equipment did. So, you can use the smaller O.D. hose unless you are going for points.

There are 3 vacuum hoses that go through the firewall right under the vacuum can.

The large hose goes to the center nipple on the vacuum can

The other larger size hose goes to the water valve

This leaves 3 hoses that tee into the vacuum supply line.
1. The small hose under the can, 2. the hose that comes from down low on the firewall of the passenger compartment, 3. the hose that comes from the A/C vacuum can that is under the front RH fender.

Here is how to connect these 3 remaining hoses....

Connect a 7/32 hose to outside nipple of vacuum can

Tee off 7/32 hose to nipple of 66 AC vacuum can under the front fender by the battery. there is only one nipple on the bottom of the can

Tee off 7/64 hose to small hose that comes from firewall under vacuum can (this line activates the A/C clutch switch)

Tee off 5/32 hose and hook to vacuum hose that enters firewall by the fuse panel (follow the main electric cable down the passenger side as it dives through the firewall. this vacuum hose handles the trunk locks, rear vents and emergency brake)

Place check valve in the line
Connect 7/32 hose to vacuum port on engine manifold

This message has been edited. Last edited by: Jim 66Tbird,