headlamps seem dim

i recently noticed on my P38 that my headlights are quite dim. realised this only when i drove a friend's identical car last night and its clear that my lights are only putting out about 50% of the light they should. this is not to do with 100w bulbs or anything else. i did notice that my lens and reflectors seem a bit dirty - on the inside and also i've been on the same set of bulbs for about 6 years as they haven't burned out. do bulbs dim over time? and is there a recommended way to clean the insides of the lamps (ie the reflectors and the inside of the glass lens)?

just nick yer mates, tell him his lights look dim then see what he does about it and then write it down just in case it happens again.

i would try buffing the outside first, if that doesnt make any difference it'll be stained on the inside, dunno how your gonna clean it, maybe one of them sonic baths???

or nick the wifes pan brush???

hahaha! i'm going to try that one on me mate!

so no way to prise off the front lens and then seal it back on? i know its a bodge, just wondering if anyone's done it and lived to tell.

edit. ah... reading elsewhere they say to investigate the earth connection to the bulbs. how do i find that? don't know the second thing about car electrics.

pressure wash works - not 100%, but not bad, if they are corroded - then its noo headlights. yu can get 90% higher output bulbs - still rated at 55/65Watts tho, so legal.

take the bulb, find the earth, dunno if its the flange or one of the poles, never had to change a bulb yet.

good ideas! fanks guys!

Two points come to mind:

1. Firstly several mechanics I've spoken to in the past have said that modern headlamp lenses seem to be either designed to age and discolour (to force you to replace them), or are very poorly designed and long-term tested discolouring naturally over time. No amount of scrubbing or polishing will get rid of the tint.
   
2. From personal experience the silvering is very delicate in sealed units, the last one I tried to shine ended up all over my cloth and fingers! I would suggest proceeding down that route with great caution unless you're in a position to replace them promptly if the worst happens.

I suspect that replacement may be the best long-term solution.

be very carefull if you try to clean the polished reflector,the silver coating is very,very,very thin.i tried it on another car and the coating just rubbed off,with very little pressure.

have the lights off and thanks to all for the warnings re silvering.

Got them reasonably clean with compressed air and contemplating a dip in soapy water. decided not to mess with prising off the lenses just yet and i'm putting in a new pair of H4s for good measure. Just wanted to ask about aligning the beams when I put the lamps back on? I've seen people use calibration marks on a wall. Can anyone tell me how to mark the wall (height and width of markings for dipped and main), how far back from it the car should be etc?

Thankee!

have the lights off and thanks to all for the warnings re silvering.

Got them reasonably clean with compressed air and contemplating a dip in soapy water. decided not to mess with prising off the lenses and i'm putting in a new pair of H4s for good measure. Just wanted to ask about aligning the beams when I put the lamps back on? I've seen people use calibration marks on a wall. Can anyone tell me how to mark the wall (height and width of markings for dipped and main), how far back from it the car should be etc?

Thankee!

Just drive to the local MOT station, drop a few bob in the xmas drinks fund and ask if they wouldnt mind doint the alignment when they have a moment.

Job done, looks brilliant. What a cheap and worthwhile fix!

For anyone who'se interested:

1. Removed grill and battery cover.
2. Wiggled off the sidelamps
3. Removed headlamps - you have to disconnect the washer fluid line to the headlamp washers.
4. Removed washer wipers, bit of trim and washer motors
5. Took out all the bulbs AND the high beam bulb holder (small allen key)
6. Had a go with compressed air (low pressure) through the bulb holders and all around generally.
7. Coughed a lot in a great cloud of dust. Repeated with other headlamp.
8. Got a couple of bottle brushes (thanks Gav), some jiffy cloth and some white spirit.
9. Wrapped a brush tightly in jiffy cloth, held with lots of string wrapped around it.
10. Swabbed around the inside to pick up the dust loosened by the air.
11. Poured in about 20 - 30 ml of white spirit and sloshed it around the inside of the lens. You can’t really slosh it around the reflectors cos it'll all pour out.
12. This bit is important, tilted the assembly so all the liquid came to one side carrying whatever dirt was in it. So when it evaporates, the dirt is now in one place.
13. Allow to evaporate.
14. Jiffy swab again, gently and painstakingly. Got a TON of grime out. Use the bendy bottle brush to maximum effect. Put it through both holders for better reach (beam and beam/dipped).
15. Snipped a hole in the jiffy so a few bristles could poke out, better to clean the grooves inside the lenses.
16. Reassemble.
17. Read the tip about getting the MOT chaps to do the alignment (cheers Basher). Remembered they generally do that for free during the MOT anyway so used neighbours wall to "more or less" adjust the beams by hand. They were both high and one was wide.
18. Done. Three hours. Not only good night visibility but car looks spanking too!

did yu just get noo standard bulbs,or high brilliance bulbs?

£20 the pair???

Got a pair of 90/100s in advance but after the cleanup I tried the old bulbs again and it was fine so kept 'em in and returned the others.

edit: The thing I've been told about higher out put bulbs is that they don't give longer or wider field of coverage, just more light in the same field. Makes sense or they wouldn't be legal! If you want to see farther you need additional driving lamps or spots.

90/100's are illegal in the UK on the public highway.

not in the UK mate. and anyway, dint fit 'em in the end.

thats why i said "in the UK" .