Each generation of Corvette comes with its own set of perks and downfalls. In the case of the C3, one of the most commonly experienced problems is the dreaded "lazy eye" headlight syndrome.
Are you accustomed to waiting an extra few minutes for your C3 to warm up before pulling the headlight switch, or simply driving the first several miles of each trip with one light up and the other closed? If so, don't dismay. Many C3 headlight woes can be remedied with a simple vacuum-hose replacement. And even in a worst-case scenario-that of a failed actuator-it should only take around two hours to rectify the problem.
Over the next few paragraphs, we'll walk you through the process of diagnosing and repairing this problem on a third-generation Corvette. Although our subject car is a '79 edition, the information contained herein applies equally to all '68-'82 models.
Diagnosis
Begin by tracing all the related vacuum hoses from the actuators to the engine, and inspecting them for cracks, pinches, or holes. If you find any, repairing or replacing the suspect hose could cure your problem. Continue by inspecting the seals on the actuators themselves, repairing or replacing as necessary.
If all of your lines and seals look good, turn on the engine and listen for any hissing sounds emanating from these areas. This could help you track down the location of any hard-to-spot vacuum leaks.
If none of these steps is effective in identifying the problem, it's time to break out the tools. Check out the accompanying photos as we take you through the process.
With the car running, pull...
With the car running, pull the air line that runs from the engine to the vacuum reservoir (located at the very front of the car, just behind the actuators). If you hear hissing, that means you have some amount of vacuum reaching the actuators, which is a good sign.
If your car just has one "lazy...
If your car just has one "lazy eye," there's a simple way to check whether the problem is with the solenoid, rather than the vacuum actuator. There's a small relay that tells the lights when to open and close. Reverse the solenoids to see if it switches which one is working (shown). If so, you can deduce that that solenoid needs to be replaced. If not, your next option is to pressure check the lines. Attach a vacuum gauge, plug it into the end of the hose (where it connects to the actuator), and plug the other end shut.
In our case it wasn't an issue...
In our case it wasn't an issue with the solenoid or vacuum hoses. Once we turned on the lights, we could easily hear a loud hissing. We simply traced the lines and found that the leak was at the left actuator. Upon closer examination, it was obvious that the actuator-rod boot had cracked.
Our new actuator arrived in...
Our new actuator arrived in tip-top shape from Zip Products. We opted for the $89 complete actuator unit instead of the seal-repair kit, which costs $23.
You'll need to reach under...
You'll need to reach under the front bumper to remove them.
There are four springs on...
There are four springs on the pivot-link pin that go between the light and the vacuum motor.
Next, there's a cotter pin...
Next, there's a cotter pin you'll need to remove. It holds the actuator rod in place, which, in turn, holds the vacuum motor to the pivot-link pin. After the cotter pin is removed, the pivot-link pin itself will need to come out.
The springs, cotter pin, and...
The springs, cotter pin, and pivot-link pin are shown here in the orientation in which they should be reinstalled.
Now it's time to pull out...
Now it's time to pull out the four bolts with a 1/2-inch box-end wrench. These bolts hold the vacuum motor in place. It took us a while to decide if it was easier to remove it from the top or bottom of the car. We ended up carefully going through the top. This obviated the need to unbolt the hood.
Removing the vacuum motor...
Removing the vacuum motor once unbolted is tricky, due to the very tight fit. Slowly move the actuator toward the center point of the hood, where the space between the hood and nose allows for a little extra room. Once there, the actuator will lift out easily and not scratch your hood. Once removed, it was time for us to reverse the process and reinstall our new part to end our lazy-eye problem.
Not many tools are needed...
Not many tools are needed for this job. Total timeline for our diagnosis and install: just under three hours.