C4 Headlamp pod motor gears rebuild

[TimP]

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.


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.


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.



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.

 

[teamzr1]

Is it just the angle of photo or does the head unit need adjusting a bit as gaps in front corners showing ?

 

[Nassau65]

A lot of C4’s probably had gaps like that straight out of the showroom.

 

[TimP]

Is it just the angle of photo or does the head unit need adjusting a bit as gaps in front corners showing ?

View attachment 31643

I did each pod separately and put the first one back to the mimic the other so they are both the same. When closes the positioning and dit is really good but I must admit I was a little disappointed that when open the look like they don't fit so well. Would you have a picture of what a good set up looks like? Should the base of the pod line up with the bodywork when open?

 

[teamzr1]

Couple of examples
Bottom up front about flush with hood

 

[TimP]

Couple of examples
Bottom up front about flush with hood

View attachment 31646View attachment 31647

Excellent - that's really useful. The weather is supposed to be good tomorrow so I'll get the car out and see if I can get them to align better. Many thanks.

 

[TimP]

This looks a bit better.... although looking from this angle I think there is still a little adjustment required to make the bottom gap parallel. So much easier to adjust these than the C3 pods - clearly the GM engineers learned to do things a little simpler in the later generation.

Need a clean as well.... Thanks for the help/advice.

 

[teamzr1]

Looks good, nice job

How they look when closed, flush with hood ?

 

[Steven Smith]

Have you got a link to the headlights, I looked up the part number you put in a previous post but it always came back with a longer part number.

 

[TimP]

Looks good, nice job

How they look when closed, flush with hood ?

Thanks! - I'll check again on the when-closed fit but when I replaced them after fitting the new lamps they looked good.

 

[TimP]

Having tested the new LED headlamps yesterday at night (and rather embarrassingly, running out of fuel at the same time - what a moron) I realised that the blue main beam warning light was on whenever the headlamps were switched on, mains or no mains. Some research on the US Corvetteforum site, where a very good post describes the problem and solution, showed that this is due to the need for a ballast resistor between the the main beam connector and earth.

I will speak to classiccarleds on Monday to see if they have integral ballast with the H4 bulb that I can use. Alternatively I will make some adjustments to incorporate this in as neat as possible a way.

 

[TimP]

Have you got a link to the headlights, I looked up the part number you put in a previous post but it always came back with a longer part number.

There seem to be a number of Hella lamp units that are very similar - I ordered the -041 item but the part number on the actual light unit that arrived was slightly different (ILE 003 427-04)


I bought mine here (eBay)

https://www.ebay.co.uk/itm/395248073073?_skw=HELLA+1LE+003+427-041&itmmeta=01K5KQQY9YKB7JHH3WTTMX5MBP&hash=item5c069ef971:g:tNYAAOSwgrVl5za5&itmprp=enc:AQAKAAAA8FkggFvd1GGDu0w3yXCmi1ewC6S9UdRCWudI5ywzL9gLCLWqxRFH3KqsnBd+5Cjg/slc5k3v4BMVF4zJ147N30F9S0ryV+n8QtGQLJXrVs/qSzdRrq5LCdKaoYh91hv6SQzTkFntPdTJqjbULliAh3HS/7/Sx2tJwX+JM/GXhc/yyeJbvxEVI4hfVFQXkuvyFNAj9NZMEfK6TMWQjCddT6I2tX56ZDZ2NZBU9B/+AtscXwDD0XWZED8RB7c/vy25c9Sy+1uiOYSzLTtHUdy+jp0CGKHG+JVkqx6J+2+RcC4Cxln/FWBpuVKiI+Oj/DlUuw==|tkp:Bk9SR5Ll3_esZg

It says last one on the posting but it said that before I bought my mine so....

They are also available here (eBay again).. who apparently are authorised Hella Dealers
HELLA GENUINE OEM 1LE003427-041 LEFT OR RIGHT HEADLIGHT H4 + SIDE LIGHT | eBay UK

The hella website catalogue listing for these units is here ....it's also available on the Australian and NZ Hella catalogues which is reassuring as they drive on the left too.
https://cat.hella.com/web/public/hella/en/all/all/na/$catalogue/2/na/na/parameters/$product/1LE+003+427-041_3335/keywords.xhtml?result=1758378741958

Hope that helps...

 

[TimP]

Having realised that with the LED's fitted that the blue main beam warning light was on all the time, some research revealed (via an excellent post on the US Corvetteforum) that ballast resistors were going to be needed to simulate the current draw that halogen/incandescent bulbs take. Whilst I purchased suitable H4 ballast resistors I fitted a couple of H4 halogen bulbs that I had from the C3 project and these work fine, including the blue main beam indicator.

When the ballast resistors arrived (from Classiccarleds) I made a small heatsink to fit inside the black plastic headlamp pod. The ballast resistors get very hot in operation (up to 180C according to the packaging) and thus a way of mounting them without melting anything they are mounted on is important.




As the resistors are relatively heavy they need to be secured, thus the idea was to bolt heatsink to the pod using the two convenient holes just below the bolt mounts.


(BTW: the resistor casings are electrically isolated from the current flowing through the resistor, so mounting both on the same heatsink is ok.) However, whilst making the heatsink I realised that this wasn't a solution that made sense: The original idea was to have a UK legal, brighter headlight arrangement using LEDs that make lower demands on the electrical system. If ballast resistors need to be used the last point doesn't apply any more as the resistors draw the current necessary to make the overall system work, thus obviating the low current draw of the LEDs. The resistors and necessary heatsink/mounting bracket also make the solution rather clumsy. Thus I have decided to stay with the halogens: the bulb holders are UK legal and the bulbs give a better light than the old sealed beam units do.

The YouTue videos I have watched haven't mentioned the ballast resistor requirement so maybe some US headlight brands out there have them built in.

One other change I made was to remove the sidelight bulbs that came with the headlight unit. These are not going be used and to avoid any issue at UK MoT time in having lights fitted that don't work, I have removed the sidelight bulb and replaced them with a 10mm length of the Delrin rod that I bought to fix the headlamp motors. Coincidentally the headlamp bulbs, that just squeeze in to a rubber grommet in the headlamp reflector, are the same 12mm diameter as the rod.

 

[Steven Smith]

Having realised that with the LED's fitted that the blue main beam warning light was on all the time, some research revealed (via an excellent post on the US Corvetteforum) that ballast resistors were going to be needed to simulate the current draw that halogen/incandescent bulbs take. Whilst I purchased suitable H4 ballast resistors I fitted a couple of H4 halogen bulbs that I had from the C3 project and these work fine, including the blue main beam indicator.

When the ballast resistors arrived (from Classiccarleds) I made a small heatsink to fit inside the black plastic headlamp pod. The ballast resistors get very hot in operation (up to 180C according to the packaging) and thus a way of mounting them without melting anything they are mounted on is important.


View attachment 31807

As the resistors are relatively heavy they need to be secured, thus the idea was to bolt heatsink to the pod using the two convenient holes just below the bolt mounts.
View attachment 31805

(BTW: the resistor casings are electrically isolated from the current flowing through the resistor, so mounting both on the same heatsink is ok.) However, whilst making the heatsink I realised that this wasn't a solution that made sense: The original idea was to have a UK legal, brighter headlight arrangement using LEDs that make lower demands on the electrical system. If ballast resistors need to be used the last point doesn't apply any more as the resistors draw the current necessary to make the overall system work, thus obviating the low current draw of the LEDs. The resistors and necessary heatsink/mounting bracket also make the solution rather clumsy. Thus I have decided to stay with the halogens: the bulb holders are UK legal and the bulbs give a better light than the old sealed beam units do.

The YouTue videos I have watched haven't mentioned the ballast resistor requirement so maybe some US headlight brands out there have them built in.

One other change I made was to remove the sidelight bulbs that came with the headlight unit. These are not going be used and to avoid any issue at UK MoT time in having lights fitted that don't work, I have removed the sidelight bulb and replaced them with a 10mm length of the Delrin rod that I bought to fix the headlamp motors. Coincidentally the headlamp bulbs, that just squeeze in to a rubber grommet in the headlamp reflector, are the same 12mm diameter as the rod.

I fitted some cheap AliExpress LED's to my 86 and they work fine, I don't get the blue high beam indicator and haven't fitted ballast resistors

 

[TimP]

I fitted some cheap AliExpress LED's to my 86 and they work fine, I don't get the blue high beam indicator and haven't fitted ballast resistors

That's interesting - perhaps the earlier models have a different way of managing the headlights - it's certainly a problem for some cars and not with others. I can't offer any explanation - it might need someone with an indepth knowledge of electrics or C4s (or both) to explain it. I did put in a call to classiccarleds but they didn't answer and didn't respond to the message I left. With this insight I might try again.

 

[Steven Smith]

That's interesting - perhaps the earlier models have a different way of managing the headlights - it's certainly a problem for some cars and not with others. I can't offer any explanation - it might need someone with an indepth knowledge of electrics or C4s (or both) to explain it. I did put in a call to classiccarleds but they didn't answer and didn't respond to the message I left. With this insight I might try again.

These are the ones I fitted.

 

[CaptainK]

On my 1968 C3 I fitted a bunch of LED bulbs from Classic Car LEDs to all 4 of the front main headlights AND the little sidelight dome bulb that goes in the holes in the dipped beam outer lights.

I didn't fit a ballast resistor, and it seems to work fine. Like you, I wanted a lesser demand on the wiring for the lights, hence the LEDs. Granted 1968s, being the first year C3, have their little oddities, and this may well be one of their oddities. Handy though if that's the case.

 

[TimP]

On my 1968 C3 I fitted a bunch of LED bulbs from Classic Car LEDs to all 4 of the front main headlights AND the little sidelight dome bulb that goes in the holes in the dipped beam outer lights.

I didn't fit a ballast resistor, and it seems to work fine. Like you, I wanted a lesser demand on the wiring for the lights, hence the LEDs. Granted 1968s, being the first year C3, have their little oddities, and this may well be one of their oddities. Handy though if that's the case.

With my C3 build I have replaced all bulbs inside and out with LEDs and it has all worked really well - with no ballast resistors, just two new electronic relays for the indicator and hazard circuits. I wonder if the onset of more sophisticated car/dash electronics in the nineties made the wiring and associated systems a bit more sensitive as to how they were configured.

 

[CaptainK]

You've done better than me Tim - I've just got the front main light, and rear main lights as LED, and the door ajar inside lights. Maybe one day I'll do the rest of them.