Unexpected changes - headlights
Thread Starter
Racer
Joined: May 2011
Posts: 297
Likes: 3
From: Indianapolis
Unexpected changes - headlights
Working on a 30+ year old driver, you learn to 'expect the unexpected', especially when you start going over everything for the first time. Often (at least for me) the unexpected is that when you fix something, some other related item starts acting unusual or quits working altogether. This time I was pleasantly surprised to find something unexpectedly started working better!
I recently replaced my valve cover gaskets and repainted the covers (http://forums.corvetteforum.com/c3-t...ve-covers.html.) In the process, several vacuum lines were disconnected to get the covers off. When I put everything back together, I was careful to eliminate vacuum leaks wherever I could.
Before this work, the passenger's side headlight would pop up about half the speed of the driver's side. This has been very consistent over the past 10 months of ownership. Now both headlights pop up nearly simultaneously! I had assumed the passenger's side headlight just needed lubrication, which I will still look into eventually. Fortunately a little more vacuum has corrected it!
I've read the advice several times, but experienced it first hand this month: if your headlights are popping up slowly, or in my case, unevenly, check for vacuum leaks!
I recently replaced my valve cover gaskets and repainted the covers (http://forums.corvetteforum.com/c3-t...ve-covers.html.) In the process, several vacuum lines were disconnected to get the covers off. When I put everything back together, I was careful to eliminate vacuum leaks wherever I could.
Before this work, the passenger's side headlight would pop up about half the speed of the driver's side. This has been very consistent over the past 10 months of ownership. Now both headlights pop up nearly simultaneously! I had assumed the passenger's side headlight just needed lubrication, which I will still look into eventually. Fortunately a little more vacuum has corrected it!
I've read the advice several times, but experienced it first hand this month: if your headlights are popping up slowly, or in my case, unevenly, check for vacuum leaks!
Safety Car
Joined: Feb 2012
Posts: 4,705
Likes: 983
From: Orlando FL
when you fix something, some other related item starts acting unusual or quits working altogether.
Mine`s not a driver yet, but I suffer that same thing! Taking something apart to clean up or refurbish, and in the process, a part will snap in half, or crumble to dust! So the repair becomes a replacement!
So FEAR NOT! You are not alone! LOL!
Mine`s not a driver yet, but I suffer that same thing! Taking something apart to clean up or refurbish, and in the process, a part will snap in half, or crumble to dust! So the repair becomes a replacement!
So FEAR NOT! You are not alone! LOL!
Melting Slicks
Joined: Aug 2010
Posts: 2,207
Likes: 26
From: Ocean County NJ
Did you reconnect the same vacuum lines or replaced with new ones? Strange if using the same lines made a difference in operation, unless the lines were loose before you disconnected them? It always seems like a huge victory when you can fix something. Most of the time, it does backfire and more work is required. Nice win!
Melting Slicks
Joined: Jun 2011
Posts: 2,096
Likes: 15
Yes totally agree. I have a 82 with the crossfire and anyone who owns one knows how critical vacuum lines are to the smoothness of running. I have found several lines that were cracked and dry rotted. Replaced many of them and now the crossfire runs very smooth and the headlights come up twice as fast. Good job 
Thread Starter
Racer
Joined: May 2011
Posts: 297
Likes: 3
From: Indianapolis
Did you reconnect the same vacuum lines or replaced with new ones? Strange if using the same lines made a difference in operation, unless the lines were loose before you disconnected them? It always seems like a huge victory when you can fix something. Most of the time, it does backfire and more work is required. Nice win!
Drove it again tonight, and the headlights popped up in perfect synchronization. There are several vacuum lines I want to replace, but I am afraid of messing with it now that it works so well.
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
Thats good information and a good story to hear. I am working on my 72 now and am in the process of replacing all of the vacuum lines. I am waiting for my wiper door and headlight vacuum kit to arrive. I figured if I was going to go through the trouble of replacing these lines, I might as well do it right and get the color coded lines.
After checking into the headlight vacuum lines I am glad I ordered these.
From your story with the bolt in one line, and a ball bearing in the other, there seems to be enough vacuum loss or route issues to cause the headlight delay.
kdf
After checking into the headlight vacuum lines I am glad I ordered these.
From your story with the bolt in one line, and a ball bearing in the other, there seems to be enough vacuum loss or route issues to cause the headlight delay.
kdf
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Melting Slicks
Joined: Jun 2011
Posts: 2,096
Likes: 15
No, generally one will be slightly faster than the other. Any time you have two vacuum canisters they will never be timed perfectly. Go to youtube and put in "hideaway headlights" and you will see all makes will have one faster than the other unless they use one canister with a rod controlling both doors.
Thread Starter
Racer
Joined: May 2011
Posts: 297
Likes: 3
From: Indianapolis
Although more vacuum might help, as in my case, there are several variables to consider: do the moving joints need lubrication? If so, is one side more worn than the other? Is the spring tension/resistance to movement the same on both sides?
On my car, I know the previous owner replaced a lot of the headlight components, so I have fairly new hardware. In theory, the headlights were designed to open at the same time. In practice, well - this is a 35 year old design! In reality, my situation is in part good fortune, which is why I am pleasantly surprised.
On my car, I know the previous owner replaced a lot of the headlight components, so I have fairly new hardware. In theory, the headlights were designed to open at the same time. In practice, well - this is a 35 year old design! In reality, my situation is in part good fortune, which is why I am pleasantly surprised.
Safety Car
Joined: Sep 2005
Posts: 4,062
Likes: 103
From: Southeast, Tennessee
St. Jude Donor '09 thru '26
No, generally one will be slightly faster than the other. Any time you have two vacuum canisters they will never be timed perfectly. Go to youtube and put in "hideaway headlights" and you will see all makes will have one faster than the other unless they use one canister with a rod controlling both doors.
mine have been completely rebuilt new everything including the lines and that is exactly how they operate. one slightly ahead of the other.
Race Director
Joined: Jul 2001
Posts: 15,892
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2nd Gear
Joined: Mar 2012
Posts: 2
Likes: 0
my lights pop up fine when I use the pull down over ride switch on my 79, but not with the headlight switch. I replaced the actuators, relays and the head light switch. I have not replaced the check valves or all of the lines. I guess I have some loose lines.
Racer
Joined: Feb 2007
Posts: 271
Likes: 25
From: Buena Vista Colorado
Check the hose connections on your headlight switch. I think they are reversed.