Headlamp Vacuum
Thread Starter
Instructor
Joined: Apr 2011
Posts: 154
Likes: 0
From: Grand Haven Michigan
Headlamp Vacuum
I am in the process of rewiring and re plumbing all my harnesses and vacuum lines.
Which, I am finding out, keeps adding to parts to buy list.
One thing I noticed when I went to hook up the new vacuum lines to the front of my car, a 1971, that instead of the two vacuum actuator relay valves, there is only one. I did not see any mounting holes for a second one, unless they are hidden under dirt and grime.
My main question is, can I still make this work with one, it obviously did before but one headlight was slower to pop up then the other, but is there a way to make both work more equally?
Which, I am finding out, keeps adding to parts to buy list.
One thing I noticed when I went to hook up the new vacuum lines to the front of my car, a 1971, that instead of the two vacuum actuator relay valves, there is only one. I did not see any mounting holes for a second one, unless they are hidden under dirt and grime.
My main question is, can I still make this work with one, it obviously did before but one headlight was slower to pop up then the other, but is there a way to make both work more equally?
Drifting
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
My 69' also just has the one relay and I think they went to one mainly to reduce cost and complexity.
From a design standpoint, I would think one would also be more consistent than two since both doors receive the same vacuum signal at the same time (thus avoiding different rates within the relays themselves).
My doors also have different opening and closing rates, which I contribute to the differences between the two door assemblies from a spring tension and linkage friction standpoint as well as differences in opening/closing rate of each actuator.
The single relay itself shouldn't be the issue when it comes to different opening and closing rates.
Just my observation-
From a design standpoint, I would think one would also be more consistent than two since both doors receive the same vacuum signal at the same time (thus avoiding different rates within the relays themselves).
My doors also have different opening and closing rates, which I contribute to the differences between the two door assemblies from a spring tension and linkage friction standpoint as well as differences in opening/closing rate of each actuator.
The single relay itself shouldn't be the issue when it comes to different opening and closing rates.
Just my observation-
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Check the assembly instruction manual (AIM); I believe your car should have two relays; if so, the AIM will show where the second is to be mounted. But no harm done. The 68s only had one relay and used tees from the ports out to each actuator. You can do the same.
Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
You can get them pretty close if your lucky!
Last edited by Peterbuilt; Feb 1, 2013 at 01:51 PM.
Team Owner
Joined: Sep 2006
Posts: 31,270
Likes: 4,362
From: Westminster Maryland
Hi ej,
I believe 71 model year cars did have 2 relays.
The right side relay mounts at the very front of the plate while the left side relay mounts about half way back.
Regards,
Alan
I believe 71 model year cars did have 2 relays.
The right side relay mounts at the very front of the plate while the left side relay mounts about half way back.
Regards,
Alan
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Pivot bearing binding up will cause this, actuator pivot bushings and pins will cause this as will any other deteriorated pivot point in the system. Then add in a leaking actuator and you can see there are many things that will cause them to be slower than the other. Problem is getting them to come at the exact same time is next to impossible.
The headlamps will work off 1 relay if the system is in good working order.
Here is a video on how to test all the components on your headlamp system. It also covers a few other things as well.
http://willcoxcorvette.com/product_i...ducts_id=27610
The headlamps will work off 1 relay if the system is in good working order.
Here is a video on how to test all the components on your headlamp system. It also covers a few other things as well.
http://willcoxcorvette.com/product_i...ducts_id=27610
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski