Headlight Rotation No. 1
I have a '67 convertible with a 327. I have always had problems with the headlights. They don't rotate easily, and usually have to be "helped" by rotating the knob on the back of the motor. I have replaced the motors and installed a gear kit. I still have these problems. I can't tell if the motors don't have the power to rotate the headlight assembly around or if there is binding in the assembly. I do know that the electrical connections are all good, and that the motors are getting power. Is this a common problem?
Brian White, Via e-mail
Headlight Rotation No. 2
I would like your advice on "fixing" a lazy headlight on my '66 Corvette. When I activate the switch for down or up of the headlights, I have the driver-side headlight rotate at a much slower pace than the passenger side. Is it a problem with the motor or something else?
William H. Hahn, Via e-mail
Let's separate the rotating headlight system into three categories, each of which can cause the problems that are experienced in the real world, especially in cars of this age. The first category would be the headlight housing-the rotating assembly that mounts to the front of the car. Two shafts from the housing pass through two spherical bearings that are held by two bearing cups that are mounted to the car with three bolts each-in a nutshell. The housing is held center in the opening of the front of the car by a pair of "stops" on the shafts: one ring-shaped on the outboard shaft, and the other "Y" shaped on the inboard or driven shaft. To check the ease of rotation of the housing, the motor must be disconnected from the assembly. Pull the hairpin clip from the stub shaft of the inner bearing housing, and remove the small bolt from the mounting plate of the motor. Lay the motor aside and check to see if the headlight housing has any drag to it. You should be able to watch the housing complete a full cycle from open to closed or vice versa after simply starting the rotational effort with your finger. Yes, it should rotate that easily. If not, locate whatever is binding and make a repair. Chances are you'll find bodywork, corrosion, improper hardware, improper mounting procedures, or the sheer genius of some prior shade tree atta-boy that had a hand in it. If necessary, take the assemblies out and fully disassemble them. Clean and inspect the parts, and repair or replace as necessary. Don't forget to lubricate the shafts where they pass through the spherical balls, and pack a little extra grease in the cup to help keep moisture out. When they rotate easily with the one-finger test, you're ready to move on.
The second category is the headlight motor. Remove the headlight motor from its wiring and take it to the bench for testing. With a good 12V battery at hand, make two 10-gauge jumper wires from the battery posts to test the operation of the motors. Use a female terminal on the end of the positive wire to connect to one of the male spades inside the ivory-colored plug of the motor. After you've made the positive connection, make the negative connection by holding the negative wire to the housing of the motor. You should see the small wheel of the motor spin freely, and without pause or interruption. Pull the negative wire from the housing and connect the positive wire to the other terminal within the ivory plug. Reconnect the negative wire, and you should see the wheel spin once again, only in the opposite direction-again, without pause or interruption. Both motors should spin freely, evenly, and at the same speed. If not, look for problems within the motor. The most likely problem is the aluminum drive gear that is turned by the screw on the end of the motor armature. I guess this would make it the driven gear, except that it drives the headlight housing. Look for worn, distorted, or flattened teeth on this aluminum gear. Replacements are readily available from all of the Corvette parts vendors. Look out for the cheapie aluminum gears that are still circulating out there. They won't fit the shaft of the headlight housing, which renders them absolutely useless. Be sure to pack some grease in the gearbox of the motor.