Left headlight raises on its own?
Racer
Joined: Jan 2007
Posts: 325
Likes: 0
From: Ocala FL
The relays are the weakest link in the system, but it's understandable. The relays have a nitrile rubber "dogbone" inside used as a dynamic vacuum seal. Holding vacuum on a part that moves is a tough job.C3's are between 25 and 39 years old. Now think about how many times that part has moved back and forth in all those years and how dry the rubber has become just because of age.
Pro
Joined: Oct 2000
Posts: 564
Likes: 0
From: Riverview Florida
Bubba 1 might have "fixed" some other problem by bypassing the reservoir which is the round bar in front of the radiator. If you can get your hands on a vaccum gage you can find out of the reservoir is still good.
First test your manifold vacuum available by connecting the vac gage to the hose coming from the check valve. With a stock cam and timing set correctly, you should have >10 inches of vacuum at idle. Jot down whatever number you get.
Then
Attach the vacuum source from the check valve to the reservoir. attach the vac gage to another port on the reservoir and cap the third port on the reservoir. If the reservoir or hoses aren't leaking you should have the same reading on the gage as the manifold vacuum test.
OR if it ain't broke, don't fix it.
PM me with specific questions
First test your manifold vacuum available by connecting the vac gage to the hose coming from the check valve. With a stock cam and timing set correctly, you should have >10 inches of vacuum at idle. Jot down whatever number you get.
Then
Attach the vacuum source from the check valve to the reservoir. attach the vac gage to another port on the reservoir and cap the third port on the reservoir. If the reservoir or hoses aren't leaking you should have the same reading on the gage as the manifold vacuum test.
OR if it ain't broke, don't fix it.
PM me with specific questions
I have been leaning strongly toward the "if it ain't broke..." scenario.
I can't find anything else on the car that needs vacuum other than the climate control system and here in FL I can live without the heater control valve opening.
Are there any other things I am missing by not having a reservoir?
Melting Slicks
Joined: Nov 2003
Posts: 2,668
Likes: 119
From: St. Charles Mo
CI 5 & 8 Veteran
Incorrect assumption about how the relay valve works. For the headlights to open the relay valce needs HIGH Vacuum to the top side of the diaphragm. This moves the slider valve UP and supplies vacuum to the back side of the acutator raising the headlight. The relay valve has a spring to return the slider to the down position, which supplies vacuum to the front of the acturator which closes the lights.
68-72 vacuum diagram
Bullshark
By the way, I am thinking a strong vacuum system with no leaks will keep the dog bone up, overriding the relay spring force, and continue suppling vacuum to the back side of the actuator thereby holding the headlight down even in the presence of aerodynamics.
Last edited by Bullshark; Apr 24, 2007 at 12:31 AM.
Racer
Joined: Jan 2007
Posts: 325
Likes: 0
From: Ocala FL
Tommy, I am thinking you have it backwards???
[Bullshark
By the way, I am thinking a strong vacuum system with no leaks will keep the dog bone up, overriding the relay spring force, and continue suppling vacuum to the back side of the actuator thereby holding the headlight down even in the presence of aerodynamics.
[Bullshark
By the way, I am thinking a strong vacuum system with no leaks will keep the dog bone up, overriding the relay spring force, and continue suppling vacuum to the back side of the actuator thereby holding the headlight down even in the presence of aerodynamics.
High Vacuum to the top of the relay moves the dogbone up and supplies vacuum to the BACK of the actuator to close the headlights.
Brain Fart on my part - sorry to all I confused:o
