Not really an electrical problem, but I need a bit of advice on separating the glass headlight, if anyone has done it without it being too much hassle.

I have been ticking a few jobs off during the lockdown. I have one silver and one black headlight. I replaced the drivers side headlight several years ago with a silver one that I got cheap and It has been bugging me ever since. Mine is a 2000 MY and should have black headlights.
I have just bought a black one on Ebay which is in good condition but at the bottom where the two glass halves meet, there is a bit of green mold. It is between the two layers of glass so there must be a route for moisture to get through. It will only get worse.

I was thinking of splitting the glass halves somehow, then clean off the mold and re glue the halves back together.

Has anyone done it? or is it best to leave well alone?

Hi Dave,
I have read somewhere that the glass can be separated from the body with a heat gun. Carefully. I think it may have been on the AULRO site. Regards, Alan

Wow ..... a heat gun? Sounds risky.

You remove clips and gently warm the mastic sealant that holds glass ---- did that on my omega years ago ---- glass on headlight is pretty thick so should be fine

I did this last week as I'm attempting to fit projectors with clear lenses. To open it I stuck it in the oven at 150 degrees for 7 minutes. Then I got a wide flat screwdriver and pryed under the sealant to lift one side of the lens up until it comes off.

I tried the first headlight at 120 degrees for six minutes and attempted to go around the edge which resulted in damaging the lip most of the way round. I personally wouldn't consider using a heat gun as it seems like it would be much more effort with more chance of breakage.

Thanks guys. It seems that heat is the way to do it then.
I am reluctant to put it in a domestic oven. It is gas and I don't trust the temperature setting being accurate. Other half would have a fit.
I have got a fancy Dewalt heat gun with a digital temperture gauge. You can dial in anything from 50 deg C up to 600 deg C.
I will give it a try. Start off low then slowly increase the temperature.
What about sealant? non-setting / flexible ? or just epoxy the two halves together?

Once you've got it apart, I'd use a PU adhesive like Tiger Seal to stick back together, that's what's used on windscreens. The last thing you want is a headlamp that fills up with water every time it rains.

OK thanks Richard. I have got plenty of Tigerseal left after glueing on my new wheel arches. It is good stuff.

The unit obvously leaks at that point, i'd be tempted to try a bit of bleach or acetone, blown through with compressed air, before the heat option. Prob wont work, but may relieve the boredom of lockdown

I have tried splitting some before as I had a set of 2000MY black insert ones with broken glass that an owner gave me, and a set of pre 2000 ones which I figured I could try swapping the glass over on.

I tried putting them in the oven, but obviously didn't get it hot enough or evenly enough, as I had the plastic surround crack aswell. I found it to be pretty brittle when it gets warm - or maybe as I say, the oven wasn't hot enough or I didn't leave it in long enough to get the sealant loose enough for it to release cleanly.

I tried with a hot air gun and it was even worse - as I couldn't get even heat around the glass, and it just destroyed the plastic surround.

dave3d wrote:

Wow ..... a heat gun? Sounds risky.

Not as risky as the guy on Facebook using a blow torch to undo fuel lines 🤣

I am going to try and get to it today. I have spent the last few days fixing my central heating but you don't want to know about that.

From my 3D printing experience you wouldn't want to go much above 200 deg C. Even that may be too hot.
I will try it at 150 deg C first. If I can get a thin scrapper or Stanley blade in to start it off it may work. If the plastic surround is ABS, it has the highest coefficient of expansion of any plastic, which means it is more likely to crack.

How is the weather in NZ Marty?

It didn't go well.
I got the headlight out of the carrier ok, then I tried using a heat gun and a bit of levering to free the glass away from the plastic back.
The plastic surround broke in several places. It is very fragile and not very flexible.
I figured that was it, end of story, so I cut the entire edge off the plastic with a small Dremel cutting disk.
The glass came away eventually. At least now I can see how it is constructed. It is not two glass halves. It is just the glass lens glued to the plastic back with a foam gasket inbetween. I might be able to salvage it by glueing it back together with some Tiger Seal.

That's pretty much what happened to the ones I tried - but figured as they were already knackered, with the glass in bits, it was worth a go.

Weather out here is nice... though almost too hot at times - especially when I was working outside for 7 hours today... .but I definitely have a tan now!

I genuinely do miss being at home with my own stuff around me and the RR to drive - but the work is keeping me going, as I'd have been even more crazy than I already am if I was sat at home still with no work!

The plastic back to the headlight is made of similar plastic that light switches are made of. A very hard plastic that is thin and fragile.
It is game over. There is no way anyone could get it apart in one piece. No one else try it.
I don't fancy glueing the lens back in with Tiger Seal either. I have gone off that idea. The lens might fall out in the road!
I will look round for another headlight.

I was in NZ 6 or 7 years ago for a 6 week holiday, North and South Island. Scenery is fantastic.

Dave I tried a heat gun on the broken lamp on my TT (RIP now) that the garage broke and hid under plastic trim, and that didn't go well either. The plastic heated up and went milky.
I think some people are gifted, some are lucky and the rest are mortals like me hahaha