C4 Headlamp pod motor gears rebuild

TimP

CCCUK Member
Having found a set of left hand traffic (dip to the right, RHD) lights for the C4 it was time to fit them and also to cure the clack-clack-clack sound that goes on for 5 or 6 seconds whenever the pods are raised or lowered. I believe this is quite a common problem with C4 where the plastic gear set in the motor disintegrates through old age. Thus two jobs to be done but a little easier to do together with everything on the bench.

There are a number of you tube videos that cover this repair but I chose this one (see link) from Mirrock Corvette in the US (Pennsylvania judging by the accent) which was really nicely explained. It also shows how the motors can be rebuilt without the replacement gears and just uses a 7/16th rod of Delrin to form the replacement parts.

C4 Headlamp motor rebuild -Mirrock Corvette

I won't repeat what can be seen on the video but here are a few pictures that show how it turned out on my '92.

The inside of each motor gearbox had the tell-tale powder of the disintegrated gear although the main gears that engage with the worm drive on the motors were both in good condition.
C4-H4 Lights13.jpg C4-H4 Lights10.jpg

Once cleaned three 11mm lengths of the Delrin rod were cut off for each pod. They are supposed to be 7/16" but I could only get 12mm which is a tad too big (7/16" = 11.1mm) so they had to be gently sanded down to the right diameter before everything would fit nicely.
C4-H4 Lights14.jpg

Careful remembering where all the factory shims went, reassembly was pretty straightforward. I used silicone grease to pack the new gear set. The most difficult thing to do seemed to be to get the electrical headlamp connector to fit back on its mount in the side of the front wing - it took ages, I was probably doing something wrong. The time to do both pods was about 4 hours.

The headlamps (fitted with LED H4 bulbs) seem to work ok but I will take the car out late one evening this week to see how they are at night. They will probably need some alignment but I can't believe that they will be any worse than they were before.

C4-H4 Lights16.jpg C4-H4 Lights15.jpg

Quite pleased with the result: the clack-clack has gone and they index round noiselessly. These should now be UK legal - they are E-marked and hopefully should be good deal brighter than the originals.

I still have enough Delrin rod to fix about 6 more headlamp motors so if anybody wants some, just let me know.
 

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