C3s4me

I must not be searching correctly but I am sure this has been addressed already. Sorry if it is redundant. I just recently put my 69 tri power back on the road and thought I fixed the headlights... But i went for a Sunday drive and had an opportunity to accelerate pretty hard through the gears on an old back road that is not traveled. When I did this one of my headlights came all the up and the other half way up on their on. So, I have somewhat fixed my headlights but still have a bug or two left. Any advice on where I should look first would be appreciated. The check valve seems to be good but what about the PVC valve? I know that vacuum drops on hard acceleration and the fail safe is up for the lights....Thanks for help! Russell

MelWff

you have a vacuum reserve tank I believe drivers side area of brake booster under fender. Sounds like you have a vacuum leak or the check valve for the tank isnt holding vacuum.

C3s4me

I checked both and they checked good. Although I was suspect of the check valve and will test it again. This time with a little more scrutiny...

Revi

What do you mean by "fail safe is up for the lights"?
Losing vacuum will not make the headlights pop-up. If this was the case, anytime you shut the car off the headlights would pop-up and stay up until vacuum pulled them back down once the car was started.

Vacuum raises the headlights up (and over center on the hinges).
Vacuum lowers the headlights down (and over center on the hinges).
Once the headlights are "over center" either up or down is where they will stay when vacuum is lost.

Zoix

Make sure all your springs are there. I believe (4) is what there should be.

Dave J

There is only one component that switches the vacuum going to the actuators, and that is the relay(s). I believe most '69 cars only had one headlight relay. If you have an internal leak between the piston /piston bore surface, the reduced level of vacuum could cause your symptom. Check your relay for any vacuum leak. Do you have a Mityvac?

C3s4me

Yes I have a mini vac ...I recently replaced relay between front headlights which got them to start working again....Thanks for the help...and additional knowledge the board gives....Russell

C3s4me

Springs have been replaced...thx

C3s4me

I was told possibly incorrectly that the headlights had a failsafe so if you lost vacuum they would at least be in the up position I guess that could be wrong....so they were completely down when I started this day time journey and did not attempt to turn the headlights on and they popped up during hard acceleration The relay in the front between the headlights has already been replaced what are your thoughts.....

Dave J

The headlights are designed to fail safe to the up position upon loss of "Control" vacuum. Assuming your check valve is indeed good, you may have a leak in the balance of your control circuit. Does your wiper door work ok?

Iceaxe

If that were true if you plugged or unplugged the vacuum line the headlights would open, which they don't.

C3s4me

Wiper door does not work at all...It is in the open position... That's the next project to tackle...

Dave J

I can walk you through this if you want, just let me know. I've fixed lots of them.

If you want to test the integrity of the headlight control vacuum circuit, here's a simple test you can do.
1 - Pull the wiper override **** out all the way. That will effectively block vacuum from going to the balance of the wiper door control system, and seal it.
2 - Plug the control vacuum hose at the headlight relay, sealing it.
3 - Connect the Mityvac to the small hose at the check valve. If the headlight control circuit is leak free, it should hold vacuum when you pump it up. If it does hold vacuum, leave the wiper override pulled out, reconnect the hose at the check valve, and at the relay.
4 - Start the car, and duplicate what you did when the H/L doors popped open. If the doors stay down, push the wiper override in and repeat the test. If the doors act up again, your wiper override switch is probably toast.

If you do this, let me know how it worked out..........Dave