vacuum sys questions
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
vacuum sys questions
On my 1972 coupe I am having problems with my headlamp doors and also with the wiper door opening when the car is started. Once the car is started and vac pressure builds up, the wiper door opens and then shuts back down, it isn't open for even a full minute. Also the headlamp doors open up and stay open. The headlight switch is never pulled at this time and the wiper switch is not actuated. When you do pull the headlight switch it makes no difference other than turninng the lights on. When you turn the switch off the lights go out but the headlamp doors stay up and open. I have DocRebuilds system guide and am going to start going through it but if anyone has a quick simple answer please feel free to point me in whatever direction that may help. Thanks so very much!
Remember our veterans today... Thank you for serving...
Sully
Remember our veterans today... Thank you for serving...
Sully
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
thegazman
Tom...
These types of vacuum leaks are difficult. I suggest you start at the vacuum source and work your way through the vacuum system. It may be worth buying new hoses and replace them as you go. Your old hoses are over thirty years old. I noticed you went to OSU. Great school! I now live near West Virginia University. Have you heard of the Mountaineers?
Good luck with the vacuum.
Ken
These types of vacuum leaks are difficult. I suggest you start at the vacuum source and work your way through the vacuum system. It may be worth buying new hoses and replace them as you go. Your old hoses are over thirty years old. I noticed you went to OSU. Great school! I now live near West Virginia University. Have you heard of the Mountaineers?
Good luck with the vacuum.
Ken
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Tom...
These types of vacuum leaks are difficult. I suggest you start at the vacuum source and work your way through the vacuum system. It may be worth buying new hoses and replace them as you go. Your old hoses are over thirty years old. I noticed you went to OSU. Great school! I now live near West Virginia University. Have you heard of the Mountaineers?
Good luck with the vacuum.
Ken
These types of vacuum leaks are difficult. I suggest you start at the vacuum source and work your way through the vacuum system. It may be worth buying new hoses and replace them as you go. Your old hoses are over thirty years old. I noticed you went to OSU. Great school! I now live near West Virginia University. Have you heard of the Mountaineers?
Good luck with the vacuum.
Ken
Sully
Team Owner
Joined: Sep 2006
Posts: 31,267
Likes: 4,362
From: Westminster Maryland
Sully,
The vacuum system is VERY difficult.
The system has two parts, the thin hoses CONTROL the relays that tell the actuators to stay closed or to open; the thick hoses supply vacuum to the actuators to POWER the headlight and windshield wiper doors up or down.
My GUESS is that your CONTROL side is leaking and thus not signaling the actuators to stay closed when you start the car. Even if you have no vacuum in the system the CONTROL side activates first (because it uses small hoses) and signals the actuators to stay where they are as they get vacuum.
Remember this.... Chevrolet Service Departments got together and had the fellow who designed the headlight and wiper system assasinated.
Regards,
Alan
The vacuum system is VERY difficult.
The system has two parts, the thin hoses CONTROL the relays that tell the actuators to stay closed or to open; the thick hoses supply vacuum to the actuators to POWER the headlight and windshield wiper doors up or down.
My GUESS is that your CONTROL side is leaking and thus not signaling the actuators to stay closed when you start the car. Even if you have no vacuum in the system the CONTROL side activates first (because it uses small hoses) and signals the actuators to stay where they are as they get vacuum.
Remember this.... Chevrolet Service Departments got together and had the fellow who designed the headlight and wiper system assasinated.
Regards,
Alan
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
well dug around under the hood but didn't find any bad connections. near the filter nor the other little connector. I am going to try to check under the dash tonight and then around the relays also...something tells me since both parts of the system are acting up it is probably around the connections for the override switches...
fingers are crossed...
Sully
fingers are crossed...
Sully
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Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
look at the check valve carefully, it will cause these symptoms if it leaks. It allows the Vac to leak away while the engine is off. It is supposed to keep the vac system charged for some time with the engine off.
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Update
yep.... im an idiot... I went through and messed some more with the headlight switch... found there was no vac coming in on the white line. Got down underneath the dash and traced the line across to the wiper door solenoid area where I could see what the problem was. The line was pinched off. When I had reinstalled the steering column the white vac line had become trapped.... completely pinched off.... so after correcting that and reassembling the lower dash I fired the car up and low and behold the headlamp assemblies dropped.... see I told you... Im an idiot
hope that makes everyone smile for the weekend! Im starting drinking early this day... a patient brought me back some Yuengling Beer froma trip to South Carolina... my Favorite... we don't get that stuff here in Arkansas...
Sully
hope that makes everyone smile for the weekend! Im starting drinking early this day... a patient brought me back some Yuengling Beer froma trip to South Carolina... my Favorite... we don't get that stuff here in Arkansas...
Sully