As the sun set it became noticeable that the throw from the E38's Xenon dipped beams terminated around a few yards from the front of the car - all well and good on the lit section of the motorway, but absolutely lethal on the country roads! Fortunately, this problem is not too tricky to fix.

There are two level-sensors for the Xenon lights, these ensure that the dipped-beams do not dazzle oncoming drivers no matter what load there is in the boot. These are fitted to the front and rear suspension. Here's the rear sensor:

And here's my front one:

That's probably not quite right! The lower balljoint has failed, the sensing arm is well out of the normal operating area, the levelling system is playing it safe and has set the Xenon aim to the lowest setting.

Right, let's get on with fixing the problem - the arm is available as a separate part:

To remove the arm from the sensor, use a 10mm open-ended spanner and a 10mm socket:

The suspension clamp is fixed with a spring clip as shown below:

So, use a flat-bladed screwdriver to open the clamp:

And use the tool-tray adjustable pliers to fit the new one (probably should have re-taken the photo):

Use the 10mm open-ended spanner and the 10mm socket to fit the new arm to the sensor - and you are done:

All done, time for a cup of tea!