Lucas P100 Headlamps

Here’s a new something to ponder.
I took apart my P100 headlamps today, and I discovered the left hand bucket shell is painted black on the inside. That’s the one that dips.
Why would it be black inside?
Was it a law, something to do with the wartime blackout, when everybody in England that could get petrol was driving around with one dipped headlight?

Second question.
There is a Lucas cloisonne emblem on the top of the outer chrome rings. Anybody know how to remove them?

Sorry, I wasn’t able answer your radiator question despite dismantling and reassembling several for rechroming. Untwisting and retwisting the tabs is necessary and frightening due to metal fatigue. I just can’t remember but I think I removed the chromed slats from that cross piece then just slid it sideways to get it out of the shell.

My P100s are both the same buff colour inside as are all the other shells that I’ve seen. War time shades looked like this:

I’ve no experience of removing the crests.


Did you want to remove the Lucas badges to re-chrome the crest bracket? If so, check with the electroplater as mine said it is not a problem to re-plate in situ as the enamel is unaffected. Similar to replating the sidelight lens surrounds. These can be done with the lens in place.

I’ve not seen how they are attached but I think they are sweated on with solder.

There are some classic parts suppliers stocking replacement badges but they are too wide, at 19mm, for the model of P100 on the Mk IV.


Thanks Peter and Peter.
My Lucas emblems are 19mm x 24mm.

Apparently you can still find the headlight covers. There were several types.
Here’s some info about them.

The regulations mention painting the reflector black.

It’s strange that someone would paint the inside of the shell. Maybe he was getting a reflective glow when it was dipped?

But the visibility must have been poor. These two failed to see a bomb crater.

HM the King had one on his Daimler.

That’s Princess Elizabeth opening the door.

Peter, do you think this is true of the fog light buckets? There are macarta electrical mounting parts riveted inside. I would rather not drill out the rivets if I don’t have to.

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Yes, the exposed metal parts are plated but any vitreous, plastic, Bakelite surface, etc is nonconductive and is therefore bypassed. (These items can be plated using a different process). I was trying to work out a way to re-plate a sidelight lens rim and successfully prised the rim off. It was going to be a failure but I took the bits around to the plater and he thought I was a bit dumb and explained it is no problem to re-plate assembled. But any alloys like aluminium, mazak, will be plated but they might be better to be masked as it is likely to lift and flake.

I have had the pressed steel base assemblies for minor lights like tail lights re-zinc plated without any affect on the electrical parts as they are electrically insulated from the bases.

That blackening of the inside of that shell looks like someone’s crazy idea for something, but it would have no effect on the lamp’s performance. I would strip it out. Just a note from my experience with replating headlamp shells: the inside of the shell receives a light non-glossy plating. This is because it is difficult to have the path of the ions turn inwards as it is not the shortest path for transfer. But that’s good because we don’t want or need any special finish there.

I did a little experiment with the dipping headlight, and because the entire reflector moves, you can get a little bit of reflection from the inside of the outer shell.
So I think that’s why the owner painted the inside black.
Anyway they’re off to the plater. $720 for two shells, two rims, two posts and two handles. I should see them again in 4 months.

On to the next question.
There was a rubber sealing ring inside each, sealing the tri-bar rim to the reflector dish. One came out in fair condition but the other came out in 10 pieces.

I don’t find these in Worcester Classic Spares.
Does anyone know about somebody else that might reproduce these?

I’ve been looking for them as well, Rob, but so far nothing. Both of mine crumbled and fell apart during disassembly. I’ve been looking for something similar to use, but haven’t come up with anything. I was thinking of trying to cut down and trim a windshield gasket to fit.