Story Mark Kaufman
Reprinted with permission
Many a C5 owner has heard that unmistakable machine gun sound emanating from the front of the car when turning on the headlights. And if that noise isn’t annoying enough, at least one of the headlights doesn’t come up, or doesn’t go down.
Anyone who has gone through this knows the fix is to replace the factory nylon gear in the headlight motor with a replacement bronze gear.
But what’s up when the gear has been replaced – by a dealer – and it happens again? Certainly the teeth on the bronze gear have not worn down to the point where they disengage from the motor drive gear. When it happened on our subject 2001 convertible, we popped the hood and discovered that epoxy used to hold the gear cover on the motor had failed and fortunately was lying beside it. As a result there was enough play on the gear shaft to allow it to disengage from the drive gear and “rat-a-tat-tat-tat-tat-tat!” each time you tried to use the lights.
Corvette Central has a headlight motor rebuild kit (1997-99 models here, 2000-04 models here) that offers a perfect solution. In addition to a bronze gear for those who need it, the C-Central kit also includes a T-bracket that fits over the gear housing cover, keeping it in place even if the epoxy fails.
Follow along with us as we not only rebuild the motors on both headlights of our C5, but using the kit from Corvette Central will prevent us from having any more trouble in the future.
We elected to remove the entire headlight assembly from the car, rather than just the motor. This not only provides easier access, but also allows you to change your headlight bulbs at the same time. A word to the wise: don’t remove both assemblies at the same time. It sure is handy to have a reference when re-installing the assembly.
1. If your headlight isn’t already in the fully up position, you’ll need to get it there manually before removing the assembly. Remove this rubber cap and turn the knob on the back of the headlight motor counter-clockwise until the headlight reaches its apex. It may take quite a bit of turning before the headlight begins to rise.
2. Next, disconnect the power to the headlight. The power connector is located immediately behind the headlight motor. Remove the connector from the tab that holds it in place, lift slightly on the snap that holds the two parts of the connector together and pull apart.
3. Using a Phillips screwdriver, remove the three screws that hold the black plastic headlight bezel in place. Two of the screws are easily accessible on either side of the headlight. The third is at the back of the bezel on the hood side of the assembly. Then slide the bezel forward to remove.
4. This shows the tab on the top of the bezel that slides onto a clip on the underside of the headlight cover to help hold it in place. As you slide the bezel forward, you’ll need to work it loose from the clip. Pay attention now to how these two pieces mate up. It will make it much easier to reassemble later.
5. Next, remove the headlight cover. This isn’t absolutely necessary, but it certainly will avoid any accidental scratches! Remove the four T-15 Torx screws holding it to the assembly. There are one on each side, and two in back.
6. This shows the positions of the six bolts that hold the headlight assembly in the car. The front of the car is to the left of the photo. The bolts at the rear (to the right in the photo) require a 10mm deep socket to remove. We found a ¼-inch ratchet works best … it’s a pretty tight fit! Use a ½-inch socket to remove the bolts toward the inside of the engine compartment (at the top of the photo). After removing the bolts, lift the driver’s side headlight assembly out. Be careful not to scratch the front clip or the fender as you lift (note the microfiber towel covering the front clip). The passenger’s side headlight has an additional wiring harness you’ll have to remove before lifting out.
7. This is the driver’s side assembly removed from the car. Note that on this side, the gear cover is still in place. That’s because it’s against the assembly, on the backside. That was not the case with the passenger side, where the cover is toward the engine compartment side and left exposed.
8. Before removing the motor from the assembly, you’ll need to unplug the wiring harness from the back of the bulbs. Note that we labeled the bulbs with the wire color BEFORE removing!
9. Remove the motor from the headlight bracket by loosening the three nuts and bolts shown here. There’s a fourth nut on the back of the shaft in the middle of the gear housing.
10. Once the nuts and bolts were removed, the gear cover (behind the gear in the photo) is easily separated from the rest of the gear housing. The Corvette Central kit with the t-bracket will solve that problem. If your cover doesn’t remove so easily, gently pry it from the rest of the housing. It comes pressure fitted from the factory, so if your motor hasn’t been previously repaired, you’ll need to take your time so you don’t break the cover, or the tabs on the inside of the cover. This side had been repaired by a dealer at one time … though the gear was replaced with another nylon gear! We’ll fix that too!
11. Since this motor had recently been repaired by a dealer, it appears relatively clean. Oftentimes when replacing a nylon gear, you will find broken teeth, rust and other grime mixed in with the grease.
12. Clean out the gear housing of all debris and grease. If your motor has been previously repaired, remove the excess epoxy. It should easily peel from the cover and/or the gear housing.
13. The Corvette Central kit comes with a bronze gear and the rubber insert. When reinstalling the shaft, make sure the flanges fit flush against the rubber insert. Liberally grease the bronze gear teeth, the drive gear, and the shaft using the grease supplied with the kit. Be careful not to get grease on the edge of the gear housing or the cover, as the epoxy won’t adhere.
14. Place the new bronze gear/rubber/insert/shaft into the housing. Mix the two-part epoxy that comes with the Corvette Central kit, apply to the underside lip of the cover and replace the cover. The instructions indicate there’s no need to clamp, but we weren’t taking any chances! Let the glue set for 24 hours.
15. When reattaching the motor assembly to the headlight bracket, place the Corvette Central T-bracket in position, matching up with holes that accept the nuts and bolts you removed the day before. Once the motor is secure, reattach the bulb harness, and place the headlight assembly, cover, and bezel back into their respective positions, using the other headlight as your guide. Before reattaching the power to the motor, manually lower and raise the headlight a few times to make sure all is functioning properly. Reconnect the power wiring harness and give it a test! No more machine gun sound, the headlight goes all the way up and all the way down, and with that T-bracket, it should never need repaired again!
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