74 Headlight Adjustment
Thread Starter
Intermediate
Joined: Jul 2018
Posts: 41
Likes: 2
74 Headlight Adjustment
New to me C3. Headlights were not coming up at all. Replaced both headlight actuator rod seals/boots/keepers yesterday.Lights now come up and go down. As a newbie, not sure what normal is. Start car, turn on lights, driver side pops up right away, after 5 seconds or so pass side pops up. When turn lights off, driver side goes down quickly, pass side eventually goes down. Noticed there is no filter upstream of the check valve. Do I need that filter? I have a shop and assembly manual. Is this normal?
Thread Starter
Intermediate
Joined: Jul 2018
Posts: 41
Likes: 2
Thanks Gun. I could not find the vac specs in my shop manual. What do you think is a good vac coming off the intake? I haven't had a chance yet to troubleshoot all components (there is a good video on youtube however). My son was down for the weekend to help, so I bought the act rebuild kit ($40) on a hope/hunch at the local vette shop and we got everything working. I was surprised that the vac connections are mostly slip (not barbed) and seems prone to leak to me. I used zip ties pulled up as tight as possible, until you guys tell me there is a better solution.
Team Owner
Joined: Jun 2001
Posts: 23,375
Likes: 1,067
From: Virginia USA
Go buy a Mity-Vac hand held vacuum pump so that you don't constantly have to start your engine. Install a filter. Check the check valve at the filter and make sure it's working properly.
Try this. Start the car the way the system is now then before turning on your lights rev the engine and keep it steady at about 1500 rpm for a minute or so to build up a good vacuum in the system then turn on your lights. If they come up almost together then you just may have low vacuum when you first start up your car and have to evacuate the vacuum reservoir etc. Also, close your lights with the engine running then shut down. Immediately try to turn the lights on. This will give you a rough idea how tight the system is. Or cars should be able to hold vacuum in the system to allow the lights to go up and down a couple of times with the engine not running. At least that's the way they came from the factory and who know how long a brand new C3 could do that.
Those are easy tests and should get you started.
Try this. Start the car the way the system is now then before turning on your lights rev the engine and keep it steady at about 1500 rpm for a minute or so to build up a good vacuum in the system then turn on your lights. If they come up almost together then you just may have low vacuum when you first start up your car and have to evacuate the vacuum reservoir etc. Also, close your lights with the engine running then shut down. Immediately try to turn the lights on. This will give you a rough idea how tight the system is. Or cars should be able to hold vacuum in the system to allow the lights to go up and down a couple of times with the engine not running. At least that's the way they came from the factory and who know how long a brand new C3 could do that.
Those are easy tests and should get you started.
Thread Starter
Intermediate
Joined: Jul 2018
Posts: 41
Likes: 2
Go buy a Mity-Vac hand held vacuum pump so that you don't constantly have to start your engine. Install a filter. Check the check valve at the filter and make sure it's working properly.
Try this. Start the car the way the system is now then before turning on your lights rev the engine and keep it steady at about 1500 rpm for a minute or so to build up a good vacuum in the system then turn on your lights. If they come up almost together then you just may have low vacuum when you first start up your car and have to evacuate the vacuum reservoir etc. Also, close your lights with the engine running then shut down. Immediately try to turn the lights on. This will give you a rough idea how tight the system is. Or cars should be able to hold vacuum in the system to allow the lights to go up and down a couple of times with the engine not running. At least that's the way they came from the factory and who know how long a brand new C3 could do that.
Those are easy tests and should get you started.
Try this. Start the car the way the system is now then before turning on your lights rev the engine and keep it steady at about 1500 rpm for a minute or so to build up a good vacuum in the system then turn on your lights. If they come up almost together then you just may have low vacuum when you first start up your car and have to evacuate the vacuum reservoir etc. Also, close your lights with the engine running then shut down. Immediately try to turn the lights on. This will give you a rough idea how tight the system is. Or cars should be able to hold vacuum in the system to allow the lights to go up and down a couple of times with the engine not running. At least that's the way they came from the factory and who know how long a brand new C3 could do that.
Those are easy tests and should get you started.
