77 Headlights Question
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 828
Likes: 2
77 Headlights Question
On my 77 I recently got my headlights vacuum system finally working. I was curious (I can't remember how my new 77 worked) as my headlights open one at a time then close together. They open about when one is half open the other starts to open. Is that ok and should I just leave them or do I still have to adjust something?
Thanks
Jax
1977 L-82
Thanks
Jax
1977 L-82
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
When the headlights do not open, normally there is a massive vacuum leak or there is a big mistake in the vacuum hose routing.
When headlights open slowly, or not at the same time, there IS a slow to moderate vacuum leak. Is the slower leak a big deal? Not really if all you want is the headlights come up so the car can be driven at night.
It is an issue if you want the vacuum system to hold vacuum after the car is turned off, and/or if you want atmosphere into the combustion system only to come through the carburetor.
Slow, or only one headlight at a time is a symptom of leaking seals in the actuator(s), relay(s), or both.
When headlights open slowly, or not at the same time, there IS a slow to moderate vacuum leak. Is the slower leak a big deal? Not really if all you want is the headlights come up so the car can be driven at night.
It is an issue if you want the vacuum system to hold vacuum after the car is turned off, and/or if you want atmosphere into the combustion system only to come through the carburetor.
Slow, or only one headlight at a time is a symptom of leaking seals in the actuator(s), relay(s), or both.
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 828
Likes: 2
When the headlights do not open, normally there is a massive vacuum leak or there is a big mistake in the vacuum hose routing.
When headlights open slowly, or not at the same time, there IS a slow to moderate vacuum leak. Is the slower leak a big deal? Not really if all you want is the headlights come up so the car can be driven at night.
It is an issue if you want the vacuum system to hold vacuum after the car is turned off, and/or if you want atmosphere into the combustion system only to come through the carburetor.
Slow, or only one headlight at a time is a symptom of leaking seals in the actuator(s), relay(s), or both.
When headlights open slowly, or not at the same time, there IS a slow to moderate vacuum leak. Is the slower leak a big deal? Not really if all you want is the headlights come up so the car can be driven at night.
It is an issue if you want the vacuum system to hold vacuum after the car is turned off, and/or if you want atmosphere into the combustion system only to come through the carburetor.
Slow, or only one headlight at a time is a symptom of leaking seals in the actuator(s), relay(s), or both.
Jax
Jax
Last edited by xkeots; Aug 3, 2016 at 12:16 PM.
Le Mans Master
Joined: Aug 2006
Posts: 7,431
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
New relays, actuators and all new vacuum hoses. No leaks unless when I had my arm behind headlamp switch i loosened one, but I don't hear any hissing.
This is how I test headlight/wiper door relays
