un-sharp Cutoff beam

**dunggah** · 12-23-2008 12:53 PM

is there a way to adjust or rotate the cutoff shield? There appears to be light leaking out of the lower arc of the cutoff beam on my driver side and the top arc doesn't seem to be as bright. I've aimed the lights up/down/left/right but the beam doesn't get more crisp. The passenger side looks a lot sharper.

Edit: forgot to add this is for the halogen projector

**AudiA4Turbo22** · 12-23-2008 01:36 PM

mine does the same thing, try bulb positioning.

**A4 Moda** · 12-23-2008 01:56 PM

Yup, it's the bulb.

**diagnosticator** · 12-23-2008 01:58 PM

The bulb position may be incorrect. If that isn't the problem, the projector can be removed, and the cut off focus adjusted using thin shims on one side or the other side of the cut off sheild to change the distance of the cut of shield from the projector lens. You would need to arrange a bench test setup to operate the lamp on a test stand. The rotation of the cutoff is dependent on the position of the projector as mounted in the headlight housing.

**dunggah** · 12-23-2008 02:09 PM

Thanks. I"ve tried reseating the bulb but I'll try it again. The bulb is a pretty tight fit though.

Removing the projector sounds like a big task so I'll assume its not as easy as turning a screw to rotate the cutoff plate.

**diagnosticator** · 12-23-2008 02:23 PM

Yeah, removing the projector from the housing is difficult the first time, but once the details involved are understood, having struggled with the hardest aspects involved, it's not hard after that.

To summarize the process, the adjusters need to be positioned for maximum internal clearance, and the fixed mounting point where the servo motor is mounted for remote or auto adjustment of the beam elevation is turned ccw to remove, then the wire clip at the bottom of the internal moving part, is disconnected to allow the projector to clear for removal. I realize pics are needed for this make sense, I can get some pics and post up a DIY for projector removal.

**diagnosticator** · 12-23-2008 02:28 PM

Originally Posted by dunggah

Thanks. I"ve tried reseating the bulb but I'll try it again. The bulb is a pretty tight fit though.

Removing the projector sounds like a big task so I'll assume its not as easy as turning a screw to rotate the cutoff plate.

To adjust the rotation of the cut off, the four mounting nuts need to be loosened, to rotate the projector in the direction needed, then the nuts are tightened again. The projector doesn't need to be removed to move the cut off a little bit. The nuts are 5.5 mm IIRC.

**dunggah** · 01-19-2009 10:38 PM

So it turns out it is the bulb positioning. If I don't secure the bulb with the clip, it looks pretty sharp. It seems to get realigned when it gets clipped in. Is it possible to loosen the clip so there's less pressure on the back of the bulb?

**diagnosticator** · 01-20-2009 10:18 AM

The problem with that is the beam will flicker and wiggle over bumps if the lamp is not held tightly in the projector. The focus of the cutoff shield image, can be optimized by using thin shim washers (mylar washers) between the projector reflector bowl, and the cut off shield and between the cut off shield and the lens frame. By varying the number of shims used on the forward side vs the reflector side of the cut off shield, the relative position of the cut off shield is focused to a sharp image. I use a bench test setup and a projector screen to do the focusing adjustment, but this requires that the projectors be removed from the housings.