|The MGA With An Attitude
HEADLAMP CLEANING - ET-137
If you have read the prior page on headlamp types you know that all MGs formally imported to North America originally had sealed beam headlamps. Procedure for cleaning these is pretty much limited to washing dirt and bugs off of the face of the bulb. So the real purpose of this article is to discuss ways to clean the inside of the lamp housing for other types of headlamps with plug-in bulbs. This includes the Lucas PL700 Tripod lamps and most of the standard headlamps used on non-North American MGA.
These plug-in bulb headlamps have two basic components. There is a front lens which may be fluted or plain glass, domed or flat, clear or sometimes selective yellow. There is also a rear reflector which is often silvered glass like a mirror. The Lucas Tripod lamps also have some internal parts, most notably the tripod frame that supports a small front reflector and shield. The two basic housing parts are commonly held together with a crimp ring around the edge. In between the two parts may be a sealing gasket or some form of adhesive. The gasket or adhesive may deteriorate or off-gas to supply some of the discoloration inside of the lamp, in addition to the silver reflector oxidizing.
With only the small hole in the back to accept the plug-in bulb you can't stick your hand inside to wash the inside of the lens. Some people mention un-crimping the retaining ring to separate the two parts of the housing for internal cleaning, then crimping it back together again. That seems a bit rash to me, especially if you think about doing it more than once.
My mind turns immediately to some form of chemical cleaning, but you must be careful no to tarnish the silver. Ah, so, perhaps silver cleaner would be appropriate, like those magic potions you see on TV where you just dip the silver into the juice and it is immediately clear of tarnish and sparkling like new. Then maybe rinse with distilled water and drip dry.
On 9/15/2011 Don Haynam wrote:
"I had a set that was at least 8 yrs old and very dirty. I poured some Ivory soap along with a very soft rag [apprx 10cm in dia.] into each headlight. Then using a swirling action I rotated the lights. Rinse them out thoroughly and let them dry on their own. They were put on the car in 1994 and were still clean the day they left my garage in Nov 2000".
Frank Mount suggests:
"If the units are like the 50s tripod ones used on Jags etc, it is possible to make a relatively simple tool and pry back the rolled edge of the reflector and separate the glass from the reflector allowing you to use Silvo and a soft rag to re-polish the reflector. The units that I recovered had been sitting at some time half full of water. They looked like new when reassembled".
Ian Hamer wrote:
"They are quite rare and valuable these days. I did clean the inside some 5 years ago and sealed the light bulb hole but the bloom has appeared again. I have had a look at the Le Mans units and there appears to be a sealant around the edge of the rim (reflector) and lens. I am even wondering if this is giving off some vapor which is causing the bloom on both the lens and reflector. Going to try Don's suggestion of swirling soapy water around as it lasted".
Silas Kinsey then suggests:
"It may be that the 'bloom' is mildew. Try a little bleach with the soap and see if it doesn't cure the problem. The emphasis should be on 'little'".