Headlight Vacuum cannister - do I really need it?

[OzCharger69]

The headlight doors suddenly stopped working. While investigating the problem I bypassed the cannister and bridged both vac lines together and the headlights are now working fine, better than before actually. I assume that the cannister must have a leak of sorts. So my question is, do I really need the cannister at all if the headlights work fine with out it? Is it just there to close the headlight doors after you switch the engine off?

I really could do with that space under the battery tray to install a different vacuum cannister for my brake booster.

Many thanks for your help.

 

[Kern Dog]

I suspect that it is for when the car isn't running.
If it concerns you, I've read of electric conversion kits for the 68-69 models.

 

[RemCharger]

We put an electric kit in my cousins 68 but..
If you can live with it the way it works keep a BBQ stick for the bad times

 

[OzCharger69]

I suspect that it is for when the car isn't running.
If it concerns you, I've read of electric conversion kits for the 68-69 models.

Yes I saw those kits. I like the vacuum mechanism, that slow non-symmetrical lift of the doors give it that old school look that I don't want to lose.

I just wanted to make I'm not missing anything and that the cannister didn't have some higher prupose.

 

[Kern Dog]

Relying on vacuum is fine for a fairly stock engine.
I am often amazed at the way the OEMs used vacuum to power accessories way back then. The FORDS that had vacuum operated windshield wipers though?

Super fast wipers at idle when the vacuum is high but s-l-o-w wipers as you're going up hills or passing someone.
The HVAC unit I pulled from my '70 Charger had the vacuum pods to serve the air doors instead of electrical motors. There was a vacuum storage tank under the battery tray for the HVAC system. The '70 was the start of electric headlight doors.

 

[RemCharger]

Relying on vacuum is fine for a fairly stock engine.
I am often amazed at the way the OEMs used vacuum to power accessories way back then. The FORDS that had vacuum operated windshield wipers though?

View attachment 1548163

Super fast wipers at idle when the vacuum is high but s-l-o-w wipers as you're going up hills or passing someone.
The HVAC unit I pulled from my '70 Charger had the vacuum pods to serve the air doors instead of electrical motors. There was a vacuum storage tank under the battery tray for the HVAC system. The '70 was the start of electric headlight doors.

Kern the retarded dude look doesn't apply here at all..
These cars were designed to have good vacuum. Therefore all vacuum accessories will work as delivered.. if people start hacking their cars to soup them up, that's their own undoing .

68 300s had 70 charger headlight systems, but unrelated..

 

[Kern Dog]

First off, I didn't post a picture of anyone that is retarded. You either missed the point or are simply confused.
Secondly, I mentioned the FORD vacuum wipers. Did you miss that part?
Who is the retarded one here?

 

[RemCharger]

I'll admit to being retarded, if you'll admit to bringing up ford wipers

 

[Mopar Hunter]

 

[Kern Dog]

My point was that the OEMs used vacuum in accessories that could have been powered by electricity.
Mopars never had vacuum wipers, did they?
I only remember the FORDs because my mom had a 62 Falcon when I was a wee chap. I have been a car guy since I could walk and I remember the wipers operating slowly just when you needed them to work fast. I learned why many years later.

 

[Mopar Hunter]

My point was that the OEMs used vacuum in accessories that could have been powered by electricity.

Cheaper?

 

[Kern Dog]

Maybe. There would be a simpler electrical system with fewer wires and fuses, a lower amp alternator could be used too.

 

[Tony Tee]

Maybe If the engine is turned off first. Then you turn off your headlights, you will have enough stored vacuum, and the headlight doors will close with a functioning vacuum canister?

 

[OzCharger69]

Maybe If the engine is turned off first. Then you turn off your headlights, you will have enough stored vacuum, and the headlight doors will close with a functioning vacuum canister?

I suspect so

 

[Triplegreen500]

Does the vacuum hold the doors open or closed?

The canister may be a "ping tank" of sorts - an equalizer quantity so the headlight doors don't see all the instant changes in vacuum as you drive.

Pure speculation...

 

[Richard Cranium]

Does the vacuum hold the doors open or closed?

The canister may be a "ping tank" of sorts - an equalizer quantity so the headlight doors don't see all the instant changes in vacuum as you drive.

Pure speculation...

The cannister, when properly working, stores enough vacuum to close or open the doors one time when the engine is shut off.

 

[LowBikeMike]

My point was that the OEMs used vacuum in accessories that could have been powered by electricity.
Mopars never had vacuum wipers, did they?
I only remember the FORDs because my mom had a 62 Falcon when I was a wee chap. I have been a car guy since I could walk and I remember the wipers operating slowly just when you needed them to work fast. I learned why many years later.

Actually the wipers on my 57 Ford are assisted by a vacuum diagram on top of the fuel pump. They work surprising well in all situations.

 

[Sixpactogo]

The headlight doors suddenly stopped working. While investigating the problem I bypassed the cannister and bridged both vac lines together and the headlights are now working fine, better than before actually. I assume that the cannister must have a leak of sorts. So my question is, do I really need the cannister at all if the headlights work fine with out it? Is it just there to close the headlight doors after you switch the engine off?

I really could do with that space under the battery tray to install a different vacuum cannister for my brake booster.

Many thanks for your help.

I suspect your canister has failed. My canister failed a few years ago. I pulled it out and the end piece had sucked itself in. I was able to put it back together with some JB weld. I replaced the one-way valve and it has worked great since then. IMO, it is as you suspect. Only there to close the doors if you turn off the headlights after shutting down the engine. I believe you could eliminate it if you don't mind not being able to close the doors after shut down.

 

[Tony Tee]

Does the vacuum hold the doors open or closed?

The canister may be a "ping tank" of sorts - an equalizer quantity so the headlight doors don't see all the instant changes in vacuum as you drive.

Pure speculation...

That's a good question. I've heard that some are held in the up position by either magnets or flat spring tabs that hold them up by friction. I'm sure there's a headlight door expert here that will let us know.

 

[1 Wild R/T]

Mopars never had vacuum wipers, did they?

Sorry Greg, but the answer is yes.... But they stopped around 1948....
And if the Falcon had the correct fuel pump the vacuum wipers were run off vacuum supplied by the fuel pump not the engine...

So the faster the fuel pump was run the faster the wipers ran...


But when the fuel pump failed it was common practice to install a cheap regular fuel pump & hook the wipers vacuum source to the manifold vacuum...