I have been fiddling with my headlights on my 82 now for a while. To begin with it did not have the vacuum resivoir can in the nose and the headlights worked great, both came up at the same time even. You just could not open them with the engine off. So my quest was to put it back like it was from the factory. I found a used vacuum can from a 82 that was in perfect condition and even leak check it. No leaks. After installing it and hooking up the hoses like they should be the headlight operation was degraded. The lights now does not come up together (was told that's normal) and is slightly slower but what I'm concerned about is the opening and shutting when the engine is off. They might pop up about a inch. So I bought and replaced just tonight all the hoses, both relays and actuators. Started the engine and no difference in the operation and still about a inch they come up when the engine is off. What a let down.... The only items I did not replace was the over ride switch and the headlight switch.

Now if the system was working correctly I would be able to operate the headlights with the engine off until I used all the vacuum right?? Maybe 1 or 2 up and downs??? I would think at least once anyway. So please anyone that has run in to this problem feel me in with what I'm doing wrong or what to do next.

 

Since you have change so many components in the system my first suggestion would be bypass the vacuum canister and see if the headlights worked as before. If they do I would suggest putting a vacuum gage in this system to see if the new canister is holding enough vacuum to operate the headlights.

I think and I could be wrong but I think the reason your headlights now open slowly and independent of each other while the engine is running is because you are not getting full vacuum as quickly to the headlights as before because it takes time to evacuate the canister. During this time you have lower vacuum trying to open the lights.

Good luck

 

The reason the headlights came up instantly was because the actuators were probably hooked up directly to the engine vacuum, versus the supply tank, which has to 'fill up'(?) to it's capacity. This is along the lines cgc's thinking and I agree with him. Also, if you're really going to work on the vacuum system of a C3, I agree with cgc about the vacuum gauge, but I'd go one better and get the vacuum gun as well, so you can test the various parts of the system.

 

Well I'm trying to remember how it was hooked up but keep drawing a blank on the missing canister. I do have the vacuum gun and did pump up the canister and seemed to take forever. Once I had it to roughly 10 in. van I watched to see if it would drop which it did at a extremely slow rate. My quest is where am I loosing the vacuum when the car is shut off because the headlights will only raise about a inch or so.

 

We'll I just went out to start messing with it and to my suprize with the engine off One headlight will fully retract and the other 3/4. I don't know if that's normal or not?? I also forgot to install two springs on one of the lights which now operate more smoothly..