68350hp

I was detailing the interior of my '68 today. I pulled down on the manual headlamp switch under the column so I could clean it. When I did I heard a hissing sound and a clunk. Here, the right headlamp came up. Now, the car has not run since 1988. The car was not running and the battery is dead. First off, how could the light come up with no power and how do I get it to go back down???? Can you guys help me out?

88'Cubka

It had to have gotten vaccum from someplace for it to open....

arrio76

Isn't the default "no vacume" position of the headight doors the "up" position?
When you pulled the manual headlight switch it released the cavume from the system and allowed the springs on the headlight assembly to pull them up. If only one of them came up it may be possible the other springs are weak or the the pivot mechanism is sticking a bit. It sounds like your vacume system is still ok and not leaking, since the headlight popped up when you pulled the release valve. Resetting/closing the manual headlight release valve and starting the car should pull the headlights back down.

jerryp58

Not sure how it came up, but you should be able to reach from underneath and push on the "knee" joint to lower it. I'm not sure of the official title of the "knee" joint, if there is one, but you'll know it when you see it. Anyway, it locks into place like a hyper-extended knee so when you push it, it will let the joint bend and lower the light.

68350hp

I have no idea how that light came up. The car hasen't run in 15 years so I don't see how there was any vacume in the lines. I played with that switch for at least a half an hour to see if it would go down. I didn't though. I have to try pushing on that knee joint next time I'm at the garage. Hopefully that will work.

gliot1

I was recently told that the vacuum actually pulls the lights down when shutting them off. It simply releases the light when the switch is turned on. I have not confirmed this yet..... I always though the vacuum raised the lights, but I'm told its opposite.

Graemeinvette

The knee joint will do it. But why have you not driven it for 15 years! :confused:

axcelr8

No vacuum, lights go up. Keeps you from having to drive with no lights when a vac failure occurs. I'm having the same problem at the moment.

bloodvette80

k i had to redo my vaccuum system on my 75 so I know a little about this topic. Theres a pneumatic relay for each headlight. There's a vaccuum reservoir. they are tied together. When you pull your light switch it allows vaccum to this relay which opens the vacuum reservoir to the "up" side of the actuators and the lights lift up. when you push the light switch in, the vacuum to the relays is shut off. This unturn drops out the relay and the headlight pots "down" side becomes the same plenum as the reservoir. So essentially the vaccuum operates BOTH directions, its jsut that the relay directs it to which side of the actuator. That switch you pulled under the dash is a safety so you can turn your lights on with the car off or someother problem. I find it amazing that the vacuum reservoir kept a vacuum for 15 years. But rest assure it is not spring operated (unless some freak made a home made one). And considering you pulled tha vacuum safety switch under the dash and the light popped up... I guarantee you that you've had a vacuum for 15 years. funny, i know. Maybe your wife has been driving it when your at work??? My last corvette held a vacuum for about 20 minutes. The one I have now holds it for about 2 seconds. :lol:

bloodvette80

the guys above are saying that disconnected vaccum lines makes the lights go up. Thats 1/2 true. Theres a large vacuum line that goes to the reservoir, and if you lose that line, the lights will not go up or down. If you lose the signal line from your head light switch, the lights WILL go up. by the way, that light that is in the up position, well reach under the car (I know the manual tells you never to lwoer the head lights by hand) but you'll see a joint or knuckle just at the end of the actuator, push it directly back into the actuator and the light will come down. Don't attempt to push the headlight door down. If you do this and you get the headlight down... post a picture of the carnage. :lol:

wcsinx

:iagree:

Everything he said is correct. I tore my whole system apart and rebuilt it, and it works perfectly.

Facts:

1. Vacuum pressure is responsible for moving the lights UP AND DOWN. All those springs and lever just hold the lights in place.

2. A loss of vaccum pressure at the actuators WILL NOT CAUSE the lights to go up. However a loss of vaccum pressure at a vacuum relay WILL cause the lights to go up assuming you still have pressure at the actuators.

It's like this, the relay controls whether vacuum is being diverted to the front (up) or the rear (down) of the actuators. The light switch and the override switch control whether or not vacuum is being applied to the relay. If the relay has vacuum, then it will divert vacuum pressure to the backs of the actuators. If the relay loses vacuum (i.e. you turned the lights on or pulled the override) then it will divert vacuum to the fronts of the actuators. Regardless, it's not the same vacuum circuit. If you cut off ALL vacuum to the system (i.e. both to the actuators and relays), then the lights will stay wherever they were. They will not pop up.

That's just amazing that your car held vacuum for 15 years. That's definitely a testament to it's integrity.

68350hp

The reason the car has sat for so long is the in 1988 it needed new tires. The car was vibrating badly when the car was driven. My grandmother couldn't get the tires at that time so the car was to set in the garage till she could get the tires. She never got around to getting tires for the car. The car still sits in the same garage on the same bad tires. It's been pushed out of the garage for cleaning twice in the 15 years it's been sitting. I usually go over to the garage during the summer and work on it but I don't have the skills to get it running. There is talk of getting it running in the near future. Hopefully in the next year or two.