1977 Headlights
Thread Starter
Racer
Joined: Jan 2008
Posts: 288
Likes: 0
From: Schaumburg Illinois
1977 Headlights
Ok, I have a good one for you. The guy that built my car for 2 owners ago deleted the checkvalve in the headlight system and kind of "engineered" the vacuum system. It works but it's not right. This creates 2 interesting things,
1) when I mat the gas, the right headlight pops up
2) when I shut the car off the right headlight winks at me
Now, I have the assembly manual and I bought a new check valve. I spent 4 hours in the garage tonight plumbing the lines the way the assembly manual shows and guess what? Headlights don't work.
I put it back to the "engineered" way and they work again. 
So, is there anyone out there that can take a picture of the area from just before the check valve to where the 2 lines outbound from the check valve go? The assebly manual doesn't really show where the smaller port goes and where the larger one goes. Thanks.
1) when I mat the gas, the right headlight pops up
2) when I shut the car off the right headlight winks at me
Now, I have the assembly manual and I bought a new check valve. I spent 4 hours in the garage tonight plumbing the lines the way the assembly manual shows and guess what? Headlights don't work.
I put it back to the "engineered" way and they work again. So, is there anyone out there that can take a picture of the area from just before the check valve to where the 2 lines outbound from the check valve go? The assebly manual doesn't really show where the smaller port goes and where the larger one goes. Thanks.
Instructor
Joined: Sep 2008
Posts: 222
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From: penngrove ca
Sorry I can't find my pic. but here goes-
The 2 lines from the check go to (1) back of the headlight switch and (2) to the reservoir in the front of the car.
A short vac. line goes from the front of the headlight sw to the front of the man. switch. Then a long vac. line goes from the back of the man switch (out of the firewall)to the top of the relay(s). Basically, a big circle is made inside the cabin.
The 2 lines from the check go to (1) back of the headlight switch and (2) to the reservoir in the front of the car.
A short vac. line goes from the front of the headlight sw to the front of the man. switch. Then a long vac. line goes from the back of the man switch (out of the firewall)to the top of the relay(s). Basically, a big circle is made inside the cabin.
Pro
Joined: Aug 2007
Posts: 707
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From: Pitman NJ
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Also get a new vacuum system filter to protect your new check valve.Corvette 101 says the filter is to keep contaminants from the vacuum system from getting into the engine....this is false(although it will do this)the filter was put there to protect the vacuum system from engine contaminants.
Last edited by ...Roger...; Oct 4, 2008 at 09:30 AM.
Thread Starter
Racer
Joined: Jan 2008
Posts: 288
Likes: 0
From: Schaumburg Illinois
so where do the 2 lines that come out of the firewall go? the assembly manual has the top one going directly to the white stripe line running to the front and the bottom one going into a tee to the blak line.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Here is a pic...the check valve in this pic is black plastic($5 at Advanced Auto Parts).You can see the hose going up to a white T with the little hose for the AC controls.
Last edited by ...Roger...; Oct 4, 2008 at 04:06 PM.
Thread Starter
Racer
Joined: Jan 2008
Posts: 288
Likes: 0
From: Schaumburg Illinois
and the real tiny line runs along the firewall and goes back into the passenger compartment on the passenger side right?
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Thread Starter
Racer
Joined: Jan 2008
Posts: 288
Likes: 0
From: Schaumburg Illinois
the small top line from the check valve goes to the top of the 2 lines at the firewall and the bottom line from the firewall goes directly into the white stripe line that runs to the front along the fender? also, the line from the engine to the checkvalve, are you using manifold vacuum or the port on the back base of the carb? and where is your brake booster vacuum coming from?
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
The brake booster is fed off the backside of the carb base.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
I did a quick search and found some pics that shows the vac lines to the booster and the check valve.The metal line for the booster is bent up a little but you should be able to see where they come from.
http://forums.corvetteforum.com/show...t=pics+carb+77
http://forums.corvetteforum.com/show...t=pics+carb+77
Thread Starter
Racer
Joined: Jan 2008
Posts: 288
Likes: 0
From: Schaumburg Illinois
well then the assembly manual is wrong. it shows the top line from the firewall going to the white striped line that follows the fender forward and the bottom line from the firewall going to the checkvalve....
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
Top and bottom isnt the issue its where they originate and where they end up.The grommet where the hoses come through the firewall can be rotated,its not always the same.Arrange the hoses like the drawing and see how it works.
Thread Starter
Racer
Joined: Jan 2008
Posts: 288
Likes: 0
From: Schaumburg Illinois
The manual also shows the hoses at the headlight switch in the wrong locations most of the time.
Top and bottom isnt the issue its where they originate and where they end up.The grommet where the hoses come through the firewall can be rotated,its not always the same.Arrange the hoses like the drawing and see how it works.
Top and bottom isnt the issue its where they originate and where they end up.The grommet where the hoses come through the firewall can be rotated,its not always the same.Arrange the hoses like the drawing and see how it works.
yeah, i thought about that too. i'm going to try it the way your photo shows before i wedge my 6'4" under the dash.........
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
You dont have go under too far,there's only 2 hoses.The furthest you have to go under is the pulldown bypass switch and you can switch the others under the hood.They cant be screwed up too bad.
