Excessive movement in headlite assembly

[Dennis Voiro]

Just purchased 70 Coupe and noticed that the passenger headlite assembly is for lack of a better term has too much play in it. The driver side stays firm with no motion. Both sides open up without a problem.

Can anyone recommend the process to adjust the assembly. I looked through several manuals but haven't found anything yet. The light beam ends up flashing on street signs at the curb of the road.

Thanks, Dennis

[Chuck S.]

Re: Excessive movement in headlite assembly

Dennis, if you can physically move the assembly vertically (no rotation, just up and down), then the headlight door bearings are probably worn out and adjustment is not possible. Each door has a single nylon uni-ball type bearing in an aluminum housing on each side of the door.

Replacing the door bearings is a pretty easy job, I believe this task can be accomplished without disassembling the entire door...not sure if the assembly has to be removed from the car, but it will probably be easier in the long run. You probably should buy the Chassis Service Manual for as much detailed info as possible.

If this car is a judged car, or you want to keep your car original, be sure to re-use your aluminum bearing housings since the NOS service parts and repros are made of stamped steel. The bearing portion (outer race and uni-ball) can be pressed out of the new stamped steel frames and pressed into the original aluminum housings. There is an old article in The Corvette Restorer on this bearing exchange.

[Jack H.]

Re: Excessive movement in headlite assembly

This is typically the result of improper adjustment. Your copy of the Chassis Service Manual has a section devoted to the Corvette body including things like the wiper door and headlights. In the section on headlights, you'll see there's a 'correct' proceedure for mounting the vacuum actuator can's push rod to the headlight bucket.

It entails disconnecting the push rod and adjusting the swivel hook in/out on the push rod's threaded shaft to achieve a pre-defined INTERFERENCE fit when the headlight bucket is in its fully extended (up) position. Without this proper interference fit, the bucket won't SNAP and LOCK into its fully open position and you'll have lights that 'bounce' on bumpy roads because the bucket is being held only by the vacuum actuator can's push rod.

You'll know when you have the interference fit adjusted correctly.... When you instruct the headlights to open, you'll hear positive feedback with SNAP/CLANK when they open and lock home!