I’m trying to eliminate every stinkin’ vacuum leak on my 68 and am finally down to the headlight system. So far, I’ve found and patched a small hole on the reservoir and replaced a defective check valve. I’ve gone over all the lines and I believe they are sound. The system works fine when the engine is running (i.e., the covers go up and down fast enough) but I notice that the entire system slowly but steadily looses vacuum within a few minutes of shutting the engine off. I suspect the leak is either at the switch or at one or both of the vacuum motors. My question, however, is this: once vacuum is lost in the system, shouldn’t the vacuum motors pull the covers open as a default position? Or do the motors hold vacuum themselves independent of the reservoir? My covers stay down for days despite no vacuum in the reservoir. For what it’s worth, I’m measuring the vacuum loss with a gauge spliced into the line that runs from the check valve to the switch.
Jody I believe when vacuum is lost to the actuators the springs on each side of the headlamp doors are supposed to open the doors.
Steven
Mine always open a while after the engine is shut off.
Maybe you need to check it on a line that goes from the reservoir to the vacuum motor.
The 67/68 wills stay in whatever position they are in when they lose vacuum, the 69/70 are suppose to open with loss of vacuum.
I’ll try that. I had assumed ( 
) that the entire system was on the same circuit, but maybe when the switch is OFF, the line I have my gauge on is isolated from the rest of the system. If that’s the case, then my leak is somewhere in that line.
The '67 and '68 do not have the clock spring to open the headlights like the '69 and '70. Catlover is right. It is very easy to have one year and assume that others are the same…
I’ve learned something new today. I thought all of the headlight doors defaulted to the open position regardless of year. The two springs I mentioned in my earlier post, what do the do? Are they just assist springs to help the vaccum accuators open the doors?
Steven
Go electric and your grilles will be arrow straight forever, lose the vac lines and they open in a split second in tandem car running or not. A custom like yours it is a no brainer, high dollar original car I say stay original.
Yorgle,
As you may know the vacuum motors have two chambers one for opening the doors and one for closing. You can check the ability of each of these chambers by putting vacuum on each one and seeing if it holds. The easiest place to do that is where the hoses come together in front of the radiator near the drivers side vacuum motor (the six-way connector). My guess is that one or both of your motors are leaking in the chamber that is in use when the doors are closed…this is why you lose vacuum after the car is turned off. I have four vacuum motors and the all have this problem (and all the “door open” chambers work great). If I am right you have a couple of choices. 1. Get your motors rebuilt. 2. Go electric. 3. If the vacuum loss is not so great as to cause the engine to run poorly (what is your manifold vacuum when everything is hooked up?), then you can live with it as is. You just won’t be able to open or close doors without the engine running. 4. If the leak is bad enough to effect engine performance, you can block off the hoses to the bad chambers. This will mean that the doors will open when you are running the car but when you turn the lights off the doors will not close. You can close them by hand when you arrive at your destination. Depending on how much you drive after dark and how much money you want to spend this can be a reasonable work around. It is what I am currently doing.
Thanks for all the great tips, guys. I spent some time methodically going through all of the hoses and connections and discovered three more leaks (besides the tank, which I patched). Turns out the switch, the check valve, and the driver’s side actuator are all leaking. I temporarily replaced the check valve with a universal one from the local auto parts store and that made a huge difference, but whether I go with electric as Don suggests or repair what I’ve got, some $$$ is going to be involved. Rats.
Can’t take it with you…
Jody should also consider the money for lubricating oil that he would save (that he has to use in order to not squeak when he walks). 
hello all, I have a 1967, and my headlights will not open unless I switch the feeds on the main solenoid, then they will open when the car starts, but won’t close until I switch them back. I was going to change the solenoid, but wanted to make sure that it was the part that is defective. Any other trouble shooting tests I can run to make sure?
Thanks in advance
Welcome, on a 67 only, that is the thing that would cause that problem.
Thank you, I will have to see if I want to change them over to electric. Since I have to change out that solenoid, maybe it makes sense to just swap them out for electric motors
For a daily driver/cruse I think elec would be the way to go.