Headlight Vacuum Issue
Thread Starter
Heel & Toe
Joined: Aug 2013
Posts: 18
Likes: 0
Headlight Vacuum Issue
Hey all, I have a 1978 Corvette and I am trying to narrow down where the issue is with the headlight vacuum. I am hoping that if I describe how things are currently working, I can get some tips on what to specifically address. So if the car is running, in park and I pull the headlight ****, the driver side headlight goes up somewhat slow but the passenger side goes very up slow and only about half way. If driving, and I pull the headlight ****, the driver side opens extremely slow and the passenger side doesn't open at all. With the engine running and in park, if I pull the switch under the steering wheel, both headlights will go up (little slow). Any ideas or thoughts?
Thanks, much appreciated.
Thanks, much appreciated.
Racer
Joined: Sep 2013
Posts: 417
Likes: 11
From: Brigham City Utah
I have a similar issue, drive side pops up and the passenger side I have to lift up by hand. Mine is a 1973 and who knows what the previous owner did or didn't do if anything at all. I figure the best place to start was with replacing 40 year old Vacuum lines.
You can get the complete set of lines from Eckler's, color coded and with a diagram as well.
Karsten
You can get the complete set of lines from Eckler's, color coded and with a diagram as well.
Karsten
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,599
Likes: 7,046
From: New Or-leens Loo-z-anna
This rookie always repairs the least expensive part first:
Sounds like there's not enough vacuum being supplied to operate the system.....OR.....there's enough vacuum being supplied---but it's being lost somewhere in the system
Check vacuum line connections at components and at vacuum switches for looseness or cracked vacuum hose ends.
I would think that the vacuum check valve may be going bad (it keeps vacuum from leaking out of cannister)
Of course there are another dozen possibilities
Sounds like there's not enough vacuum being supplied to operate the system.....OR.....there's enough vacuum being supplied---but it's being lost somewhere in the system
Check vacuum line connections at components and at vacuum switches for looseness or cracked vacuum hose ends.
I would think that the vacuum check valve may be going bad (it keeps vacuum from leaking out of cannister)
Of course there are another dozen possibilities
Melting Slicks
Joined: May 2011
Posts: 2,753
Likes: 119
From: Springfield Missouri
TRY cutting the ends of the vac lines off(1/2 inch) to see if they are too loose, letting them suck air. If that doesn't work, go the Willcox web site, they have a site to help with this and most problems!
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Before I went to that extreme, I'd probably cut off the first 1/2 inch of each hose and place it back on the item removed from.
Eliminate the leaking hose first... Then post back and we'll work on how to narrow the issue down if you still have it.
Willcox
Here is a video on how the parts work.
1968-1982 Corvette Headlamp Vacuum Diagnostic Help.
Here is a simple schematic on the hoses.
Eliminate the leaking hose first... Then post back and we'll work on how to narrow the issue down if you still have it.
Willcox
Here is a video on how the parts work.
1968-1982 Corvette Headlamp Vacuum Diagnostic Help.
Here is a simple schematic on the hoses.
Last edited by Willcox Corvette; Oct 29, 2013 at 08:40 PM.
