Headlight Aim - How Far Back and How High Up?

sleepysniper · 07-11-2013 04:09PM #1

Done a search for this but couldn't find exactly what I was looking for. Need to re-aim headlights on car, but as per thread title, to make the correct adjustment I assume I will need to be a certain distance back from a wall on a level surface and adjust the bulb to aim at a certain height on the wall. So my question is, does anybody know what these distances are? Its a 99 Corolla btw if that makes a difference.

mgbgt1978 · 07-11-2013 04:17PM

http://danielsternlighting.com/tech/aim/aim.html

...plenty more online. Google 'diy headlight alignment'

CiniO · 07-11-2013 04:25PM

sleepysniper wrote: »

Done a search for this but couldn't find exactly what I was looking for. Need to re-aim headlights on car, but as per thread title, to make the correct adjustment I assume I will need to be a certain distance back from a wall on a level surface and adjust the bulb to aim at a certain height on the wall. So my question is, does anybody know what these distances are? Its a 99 Corolla btw if that makes a difference.

With vertical adjustment, just make sure that your beam is between 0.5% and 2% facing downwards.
So just for every metre to the front of the car, beam must go down by between 5mm and 20mm.

Say your lights are at 700mm height on the car (from the ground), then 10 metres in front of the car, top of the beam should be between 500mm and 650mm above the ground.

mickdw · 07-11-2013 04:28PM

Its a percentage slope so you can work with any distance back from wall. Diagram give two sets of info depending on whether car headlight beam at light itself is above or below 850mm off ground.
Side to side, align kick point between 0 and 2% to left

sleepysniper · 07-11-2013 04:31PM

mgbgt1978 wrote: »

http://danielsternlighting.com/tech/aim/aim.html

...plenty more online. Google 'diy headlight alignment'

CiniO wrote: »

With vertical adjustment, just make sure that your beam is between 0.5% and 2% facing downwards.
So just for every metre to the front of the car, beam must go down by between 5mm and 20mm.

Say your lights are at 700mm height on the car (from the ground), then 10 metres in front of the car, top of the beam should be between 500mm and 650mm above the ground.

Perfect, exactly what I was looking for.:)

mgbgt1978 · 07-11-2013 04:40PM

Easy enough to do at home. We've done it to a couple of Mini's and a C5 (all passed the NCT shortly afterwards).
Just make sure to block off (or disconnect the bulb) the light you are not working on.....

dr.fuzzenstein · 07-11-2013 04:48PM

I never even considered you could do this at home. Will try this for a laugh.
Who do I bill for the re-test?

mgbgt1978 · 07-11-2013 05:00PM

Why would you 'try' this unless you needed to ????

mickdw · 07-11-2013 06:30PM

To see if the lights are correctly aligned?

mgbgt1978 · 07-11-2013 06:47PM

Assuming his car passed it's last NCT , and he hasn't whacked it since then there shouldn't be a problem.
If it needs a retest after he plays around with the alignment then it's obviously his own ineptness which caused it.:rolleyes:

dr.fuzzenstein · 07-11-2013 07:37PM

mgbgt1978 wrote: »

Assuming his car passed it's last NCT , and he hasn't whacked it since then there shouldn't be a problem.
If it needs a retest after he plays around with the alignment then it's obviously his own ineptness which caused it.:rolleyes:

Well, just from my own point of view (dunno what the OP will do), my car did pass the last 2 NCT's without issue and I see no reason for it not to pass again.
My method would be to try this out in my own garage, just look at the alignment, and do no adjustments at this time.
If this DIY test shows my lights are way, way off, I will then consider if I chance it with this procedure, or get the alignment done by a garage.
I'm leaning towards getting it done by a garage and then checking if the results match when tested with this hillbilly, sheet of plywood and piece of chalk test.
After all, the lights are aligned very precisely and with variables between different cars, suspension, tires, uneven floor, crooked walls and a lot of people just plain getting the measurements wrong, there is, IMO, a wide margin for error.
If the garage says I'm OK, the hillbilly test concurs and I pass the NCT, this could seem a viable option.
It would be silly to try this out untested and then go looking for birds in the trees till the next NCT and inevitable failure.

mgbgt1978 · 07-11-2013 08:52PM

Hillbilly test ???
People have done it this way for years. It's just a simple matter of measure and then adjust if needed.

As for using the 'professionals', how many of them have had their garage floor laser-leveled, get their machinery calibrated regularly, and don't just give the headlight alignment jobs to the 'new guy'....start him off with the simple stuff (and then charge €30 or more for their 'expert' labours).

If you follow the guides given, i.e. use a level surface, measure correctly etc. there is no reason why this method is not as reliable as the equipment the NCT centres use....I have regularly spotted them tilting the headlight alignment machine backwards & forwards just to get a car to pass. Why ???
To pass their buddie's cars, or just because they know that the machine they are using gives a slightly different reading than the one in the next lane.

If you want to see a 'hillbilly' machine check out the well-known Limerick auto electrician (in the Garryowen area). He wheels out something which looks like a 1950's bit of farm machinery, does the check at the side of the road (an old bit of cambered & ribbed concrete) and charges €25 for the job......haven't heard of one of his fail the NCT yet, despite the lack of electronics and laser-checking.

Also. if you even bothered to read any of the guides properly you may have noticed that your garage might be a bit short to do the test, but feel free to work away.

dr.fuzzenstein · 07-11-2013 09:29PM

mgbgt1978 wrote: »

Hillbilly test ???
People have done it this way for years. It's just a simple matter of measure and then adjust if needed.

As for using the 'professionals', how many of them have had their garage floor laser-leveled, get their machinery calibrated regularly, and don't just give the headlight alignment jobs to the 'new guy'....start him off with the simple stuff (and then charge €30 or more for their 'expert' labours).

If you follow the guides given, i.e. use a level surface, measure correctly etc. there is no reason why this method is not as reliable as the equipment the NCT centres use....I have regularly spotted them tilting the headlight alignment machine backwards & forwards just to get a car to pass. Why ???
To pass their buddie's cars, or just because they know that the machine they are using gives a slightly different reading than the one in the next lane.

If you want to see a 'hillbilly' machine check out the well-known Limerick auto electrician (in the Garryowen area). He wheels out something which looks like a 1950's bit of farm machinery, does the check at the side of the road (an old bit of cambered & ribbed concrete) and charges €25 for the job......haven't heard of one of his fail the NCT yet, despite the lack of electronics and laser-checking.

Also. if you even bothered to read any of the guides properly you may have noticed that your garage might be a bit short to do the test, but feel free to work away.

Well, then it's out the window anyway, since everything else where I live is hillside.

CiniO · 07-11-2013 10:59PM

dr.fuzzenstein wrote: »

Well, just from my own point of view (dunno what the OP will do), my car did pass the last 2 NCT's without issue and I see no reason for it not to pass again.
My method would be to try this out in my own garage, just look at the alignment, and do no adjustments at this time.
If this DIY test shows my lights are way, way off, I will then consider if I chance it with this procedure, or get the alignment done by a garage.
I'm leaning towards getting it done by a garage and then checking if the results match when tested with this hillbilly, sheet of plywood and piece of chalk test.
After all, the lights are aligned very precisely and with variables between different cars, suspension, tires, uneven floor, crooked walls and a lot of people just plain getting the measurements wrong, there is, IMO, a wide margin for error.
If the garage says I'm OK, the hillbilly test concurs and I pass the NCT, this could seem a viable option.
It would be silly to try this out untested and then go looking for birds in the trees till the next NCT and inevitable failure.

If you look at NCT requirements you will see that allowance of different setting is just horrendously big.
Lights can be adjusted vertically between 0.5% and 2% line. (as of picture above).
What it means in practice?
Imagine car with lights mounted at around 70cm above the ground (say this is about average).
If lights are set towards 0.5% border, then they will lit the road infront of the car on distance of 140metres.
If lights are set towerds other border - 2%, then they will lit the road in front of the car on distance of 35metres.
Both setting are NCT pass.
You must admit that adjustment doesn't need to be any close to precise to pass the test.
Most manufacturers specify the percetage for lights adjustment, and it's usually something like 1% or 1.3%.
If they are set to those setting they should lit road ahead for about 50m - 70m.
But as above, NCT will pass even if they are way out of this.

I bet barely any garage adjusting the lights bother to do it exactly as specified by manufacturer. They just set it to fit NCT borders, which doesn't mean lights are set properly.

I'd trust more my own adjustments than any garage.
I've been always adjusting my lights. Never been to any garage to do it over last 14 years. Never failed the test on lights adjustment.

Headlight Aim - How Far Back and How High Up?

Comments