Headlight adjustment

[ceedy]

Finding both headlights seem to be a bit high. even though I've never fiddled with them and always passed the Mots OK .

The Xenon's could do with lowering a tiny bit and the main beam esp on the nearside is currently handy for Owl Spotting .

The Socket head Screw adjuster doesn't seem to do much at all and how do Xenon's adjust ? if all .

C.

[LeRich]

Xenon headlights have automatic level adjuster on the dipped beam. This is done by sensors mounted to the front and rear suspension (just rear on late cars) that measure the suspension's angle and adjust the headlight level accordingly. Due to their position they are susceptible to damage, and the arms that link the sensor to the suspension can flip over.

There's a thread somewhere that no doubt some kind soul will link to which explains this further.

[T-Cut]

Originally Posted by ceedy

The Socket head Screw adjuster doesn't seem to do much at all and how do Xenon's adjust?

This shows a standard filament bulb headlamp but the HID version is similar.

The blue sprocket wheels under the bonnet are to manually set the 'default'/level headlamp beam aim. With HIDs, the suspension adjusters alter the beam height according to suspension movements above and blow the default/level position while driving. If the lamps aim too high with the car stationary, then the manual adjustment is out. It sounds like the system of sprockets, threaded spindles and sliders may have packed up. It's often just the blue sprockets that need fixing. Alternatively, the suspension adjuster arms might have been flipped (see below).

There's an up/down sprocket and a left/right sprocket for each headlamp.
Check whether the blue sprocket that meshes with the white one is actually bonded to the spindle. The spindles are knurled at the end and the sprocket just pressed on. The knurling rusts and the sprocket goes slack. I found a drop of supergloo makes a good fix. If it's not that simple, you may have to resort to some headlamp baking.

The beams may go skyward at ignition on due to flipped arms on the suspension units. You can tell by looking at front and rear suspension arms. This diagram explains.





TC