Where does this come from?

[andrew.graham97934]

Good evening all.
I was working in the wheel arch area of my X100 XKR today, busily wire brushing surface rust etc and I must have knocked this little rubber component off from somewhere. It is about 40mmx12mm and looks like a large rubber valve dust cap/
It is ridged for about half of its length and is designed to grip on to a screw or bolt I think.
Please ignore the tan colour which I think is the remnants of some sort of underseal which I am scraping off.
If anybody recognises this I would be grateful.
Also in the passenger side wheel arch, I noticed that the rear headlamp levelling sensor has broken. It has rusted and broken at the bottom where it joins the suspension.
It seems that these are no longer available so I may have to try to repair it.
Hope this isn't a daft question, but as there is a front sensor as well, how does the rear one affect the headlamps, and what effect will it being broken have?
Many thanks.

[Astromorg]

The rubber cap looks like one style of the caps that are fitted over various projecting screwed studs for both their protection and yours , but it is rather larger than any I recall seeing anywhere on my XK8.

If the rear height sensor is repairable, that may well be your best way ahead, otherwise you're waiting for one to come up on Ebay or a Jaguar Breaker's site such as AutoReserve (Recommended. Phone call for best results)

By comparing front and rear height sensor outputs, the headlights can be constantly adjusted to take care of heavy loads in the boot and, in an electronically damped fashion, variations in the car's pitch during acceleration and braking. A working, but mechanically disconnected rear sensor, will let the system work in a reduced manner. An electrically disconnected one may allow similar action, but will also create a DTC C1768, but no warning lights. Depending on how inaccurately the headlights are set at the time, a misalignment could fail an MOT

[andrew.graham97934]

Thanks for your detailed reply (as always!).
There are a couple of screws etc hanging so I will have another look.
I will see if any DTC codes are shown, but as you say, no warning lights are on.
Good call about the sensor. I will give AutoReserve a call.
It might be fixable with a little weld, but I think the steel will be too thin if it has rusted and broken, so a new bracket would be needed.
I will let you know how I get on. My MOT is fast approaching so hopefully I can either get it fixed or it doesn't affect the lights too much.
Thanks again.
Andrew

[andrew.graham97934]

Further update on this.
I rang Auto Reserve and the knowledgeable chap I spoke to said that these are a common part that rusts through so they are very hard to find second hand. He said it should be possible to fabricate a bracket so I will look in to that.
I doubt that a small weld is viable because if the bracket has rusted through it won't stand up to a MIG weld.
I will come back to this.