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MG MGB Technical - Headlights fried

Hi,

Both sealed beam headlights on my 72 Gt seem to have fried. There is this whitish whispish smoke stain on the inside of the sealed beam unit.

What is the probable cause(s)?

Ta
Iwan Jones

Iwan - I suppose you've heard the old explanation that Lucas bulbs don't really emit light at all, but they suck dark. That's why, after several years of operation, they turn black inside and eventually fail when they've sucked all the dark that they can hold.

But, seriously... the times I've seen that wispy white material around the filament is when the partial vacuum has been lost, and air has been allowed to enter the bulb. If the leak is slow, like a pinhole, the tungsten in the filament will combine with oxygen, and give you that appearance.

Now, the question is, "Why both at the same time?". I'd take a close look at the face for gravel pecks, and follow up with a good look at the tiny tube that exits the rear of the bulb. It could be that the bulb socket and/or the light housing are pressing on the back of the bulb.

Best of luck - - Alec

Alec Darnall

Iwan, I would check the charging voltage, if it is significantly higher than 14volts, it will blow all the bulbs, and then the battery.
Martin Layton

Time to buy some decent lights, Iwan.

Dump the sealed beams, go for Hellas, high power halogens, and fit relays on the switch, you will find a 200% improvement, at not a lot of cost.
M Barnfather

Thanks for your comments. I'll check the charging voltage.

Don't worry I will be fitting halogen beams on the car - just as I have on my other gt.

Also did you know that you can put on some extra strong halogen lights if its a pre Dec 31st 1972 car. I think I will; and dazzle some of those wallies that can't seem to remember to dip their beams round here - now there's a change for an MG.
Iwan Jones

Iwan,

Be selective ....don't go for those cheap Wipac ones, you will regret it'...Hellas are definitely much better, no matter which bulbs you use...I have 100's in mine, and they are brilliant.
Michael barnfather

Michael, do you get any reaction from other road users to your 100w bulbs? Have they been an issue at the MOT? Is it 100w on both beams?
David Witham

This thread was discussed between 05/09/2006 and 06/09/2006

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