Headlamp aim

[S2central.net]

Back to the bone & joint - my local motor factor has one on the shelf... My luck is maybe better today. Must remember to pickup a bottle of radweld as well - yeehaw.

[S2central.net]

13 quid all in for a new bottom joint - that'll be lunchtime ruined

[S2central.net]

Getting back on original topic - here is the NI headlamp alignment specs - pretty sure it is same across UK of course.

http://www.dvtani.gov.uk/uploads/customerservices/Headlampleaflet.pdf

Note how they don't officially allow you to adjust during test - frickin robots.

Maybe I am a bit thick today, but what is the reference point for those dotted horizontal and vertical lines ?

Is the horizontal supposed to be 850mm ?
And the vertical supposed to be centre of the lamp itself ?

[S2central.net]

Bit more digging and I think the dotted lines should intersect at the centre of the actual headlamp - nothing to do with 850mm. This link goes into some detail for LHD models but its useful - though I think rolling the car back 25ft from the wall is a bit dippy.

http://www.modifieda4.com/web/tech/headlight-aiming.html

There is a 1% sticker near the headlights - WTF is that about ?

[mcandmar]

Nice link EspenW

The 1% is how much the beam should dip, i.e. for every 100 feet the beam should drop 1 foot. That math seems to work on the link you posted, .7% of 25 meters is 2.08in.

Now i just need to find 25meters of flat ground and a wall....

[S2central.net]

FOund some info in the factory maintenance manual, but it only gives some guidance for German light alignment.

Confirms the 1% sticker is about inclination so all I have to do is find the centre of the lamps and go for it from a meter from the wall. This 25ft nonsense is all well and good if you are working pitch black and how more than 2 candle power

Anyway - tinkering with the lateral adjuster on the other side I find it is marginal so did the same drill & lockwire treatment on it. Whizzed on the new balljoint and wishbone over lunch there. And I also almost fainted when I saw a bottle of radweld work right before my eyes - by the second run of the fan - there was no more drips. Sure I'll have to buy another bottle and carry a few litres of water just in case but this takes the immediate sweat of spending ~200 friskin quid for a new rad - plus the joy of changing it.

I do hate cars sometimes, but my mood is a little brighter than yesterday. I think the score is 3:0 in my favour today - LOL

[S2central.net]

Right I am still confused about this distance expressed as %age...

On the MOT does the pitch tolerance of -0.5 to -2.0 percent relative to actual centre height of the lamp ?

Lets say the lamp centre is 400mm from the ground, then -1% pitch (in spec) would just be 4mm below centre

Or is the -1% pitch (still in spec) relative to the distance between lamp and wall - in which case for every metre I'd be looking for 1cm of pitch down.

You would think somebody could make and sell a DIY kit with a ready template for this - based on set distance from the wall - and a reliable way to find centre of the lamp.... which I guess must be where the dipped bulb is as centre of the glass lens makes no sense.

Shouldn't be this complicated and I am at least 20 miles away from anywhere with professional alignment gear.

[S2central.net]

I've read Espens link again and the A4 one that I found - they agree on 0.7% pitch for the 25ft distance from the wall for one type of lamp in the US so I think I have convinced myself that the %age pitch is related to distance from the wall... Hence why there is just two specs currently for MOT - one pitch tolerance if headlights below a certain height, another tolerance band for lights fitted higher.

Jeees

[mcandmar]

It really dosent matter how far from the wall you are, just make sure you have a centre line the same height as the centre of the dipped beam, then measure down X amount and mark a line where the beam cut off line should line up with. X being 1% of the distance between headlight and wall. I would expect the further away you are from the wall the more accurately you can align them. i.e. your going to see the bigger change adjusting the adjusters.

[S2central.net]

Agreed that the distance from wall doesn't really matter - it was to make sure the 1% was relative to that - as opposed to 1% of centre height.

I'm gonna try it in daylight 1m from the wall, but yes larger distance should see larger changes. I think I now know how I could create a template for a DIY beam alignment gizmo. I'm going to sell them for a gazillion pennies each if it works.... (I jest).

Thinking about the MOT - their beam tester is on fixed rails so unless it has ultrasonic or some other funky way to calculate distance to the car then that is surely a critical variable. Right enough the guy guides you up to a nominal point before the lamp test but that is never done really accurately.

[ericd]

deleted hadn't read enough of the thread..

[S2central.net]

So I've cooked a lil template to play with - calibrated for 1m distance from the wall - requires some coloured permanent pens and a 'polypocket' - will be lined up to centre point on the wall.

Would be easy to extend this using different colours for different distances.

If I've done this right, the beam should land between the two green lines that denote limits of pitch and break point for cars with lights lower than 850mm.

What think ye of this bit of science - I had to do proper hard trigonometry as well cos who has a protractor in their house ?

[S2central.net]

Spent a good hour with that template last night. Couple of difficulties are that my 'wall' is a garage door that isnt flat and more importantly the reflectors in these lights are more grey than silver so it was very hard to see nice defined lines on the light pattern. Still after much fiddling I was able to get both lights to look like they were in the zone. I did that at 1m, then rolled back to 3m and could see I needed another tweak so I think I did OK. Quick road test and nobody flashed me so thats a good start. All seemed ok.

Just back from the MOT centre for the retest where I was greeted by a cheery chap who said 'thats a quare a tidy one'. I smarmed him back while handing over the papers and told him I spent hours getting the headlight adjuster freed up. He says 'aww no problem' and waves me right past the lamp test area and onto the rig for the suspension test. You do have to wonder why you bother sometimes - clearly the guy is a human being who likes a shiny old Audi which is admirable, but I could have lights set to guide planes in and he wouldnt know.

As I drove up the ramp I thought I should have asked for the lamp test anyway to see if my rough method was anyway accurate, then I thought that I'd just ride the wave of love and say nothing.

He checks the wishbone, drops it off the ramp and waves me over with a big grin. He asked where I got the 'upgraded wishbone' from and looked a bit perplexed when I told him it was a spare one I had in the attic - he must think I am some sort of phreak.

Its all good and he hands me the pass cert. I am back on plan and street legal again - yey !

[mcandmar]

Result, i wish our NCT testers were like that. I have a world of pain ahead of me as i have to retest coupe on the 15th, and then the avant on the 16th.

The best bit is i only have one set of wheels/tyres that are road legal, what's the bets it will piss rain the night i have to change them over

[S2central.net]

Lucky you've gone for 5-bolts on your Coupe already then... Like your style... I was very close to swapping over S2 lights into the V6 before I remembered I'd have to frig the wiring for that.