68 charger vacuum squealing

It may be a common problem, but its new to me. I have a vacuum leak from somewhere under hood. It sounds like its coming from all over. Hard to pinpoint. I thought maybe the coffee can/vacuum reservoir can had a pin hole leak in it so I bypassed the hoses going into it but the vacuum squeal was still there. So I ruled that out. Now the squeal noise will go away when I switch on the headlights. Turn off the headlight switch, the squeal noise comes back. So does anyone know where the noise/leak may be coming from?

Hide away headlight mechanisms?

You have vacuum canisters with diagrams in them to work the headlight doors. One side opens the door and the other closes it. You have a vac leak somewhere in the close vac line or it's the canister itself.

I would agree with the above but clarify it's likely one on the vacuum pods/actuators (likely what he meant) as the cannister(under the battery tray) is under vacuum at all times.

Might try disconnecting one side at a time to isolate which side and then proceed with a hand held vacuum pump. I would not ASSume it's the cannister/pod until confirming with the pump

A tool to isolate (small kitchen funnel and a piece of fuel line). Fuel line to ear and funnel directed at suspect vac leak.
Another method I've used is get the noise generating and pinch off the various vac lines gently with a pair of pliers.
I tend to agree one of the vac motors may have a ruptured diaphragm. Much like a blade of grass held between thumbs, as air flow goes past it vibrates causing the noise.

another thing to look closely at, are the nipples the vacuum hoses attach to.
i have seen them have a small crack, causing the whistle as well.
it shouldn't be too hard to track down.
please let us know what you find.

Good point. A little contact adhesive is a good way to insure no leaks.

UPDATE............UPDATE.....................UPDATE.....................UPDATE................ Yes. Its the headlight actuator vacuum pod on passenger side. Its got a vacuum leak. So I looked on Year One and they have replacement vacuum pods....for 300 dollars apiece. And, of course, they are discount exempt. I looked at many different sites to see if someone else had the headlight pods at a cheaper price but could not find them. I know ebay has used vacuum pods at half the price but I don't want to replace a 50 year old part with another 50 year old part. So my question is: Does anyone know if the headlight vacuum pods sold at Year One, can they be found on another site at a cheaper price? Thanks

Repairable ?

Good question. Does anyone know if or how the 68 charger headlight actuator vacuum pods can be rebuilt?

that would depend on where the leak is. I would remove the pod apply a vacuum and see if you can audibly locate the leak. If not, apply 1-3 PSI of air and submerge the pod in water. let us know what you find

i second the above, but pictures of the leak would help in determining how the leak could be fixed if possible.

Also if the leak is around where the small shaft goes into the diaphragm, I put a small zip tie around mine & it fixed the leak