check valve...
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
check valve...
on my 72 coupe the headlights stay up all the time. Even if I put them down manually when the car is off, as soon as I start the car the headlights pop up and the wiper door opens for maybe 30 secs and then closes. I removed the vac check valve and I can blow through it both ways... this mean sit is bad, right? Is this the most likely cause of my problem?
thanks,
Sully
thanks,
Sully
Le Mans Master
Joined: Sep 2000
Posts: 9,078
Likes: 7
From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
Vacuum = Suck on the valve, not blow.
You should be able to suck through the single side and not the double side. You will need to block one of the doubles off while sucking of course.
Buy yourself one of those vacuum pumps. Saves a ton of time.
You should be able to suck through the single side and not the double side. You will need to block one of the doubles off while sucking of course.
Buy yourself one of those vacuum pumps. Saves a ton of time.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
check valve
Blow or suck..... either way,
you should only be able to blow- Pressure in 1 direction.
same for vacuum -suck negative pressure in 1 direction only.
if you can blow thru both directions the valve is defective.
Humans can blow only about 4 psi pressure.
69VETT
you should only be able to blow- Pressure in 1 direction.
same for vacuum -suck negative pressure in 1 direction only.
if you can blow thru both directions the valve is defective.
Humans can blow only about 4 psi pressure.
69VETT
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I think I found what you need at Docrebuild.com.
'68 - '82 Vacuum Check Valve
Maintains a vacuum supply in the reserve tank when the engine is turned off. A leaky valve will cause the head lamp or wiper doors to pop open when you shut off the engine.
Part #2771113
'68 - '82 Vacuum Check Valve
Maintains a vacuum supply in the reserve tank when the engine is turned off. A leaky valve will cause the head lamp or wiper doors to pop open when you shut off the engine.
Part #2771113
Advanced
Joined: Jun 2008
Posts: 58
Likes: 1
From: Eastampton NJ
on my 72 coupe the headlights stay up all the time. Even if I put them down manually when the car is off, as soon as I start the car the headlights pop up and the wiper door opens for maybe 30 secs and then closes. I removed the vac check valve and I can blow through it both ways... this mean sit is bad, right? Is this the most likely cause of my problem?
thanks,
Sully
thanks,
Sully
Get a copy of the vacuum diagram and start tracking down the problem. Make sure the headlight override (under the steering column) is pushed in!
We're available for questions!
-- brooks
