Thanks Richard,
Those were invaluable.
I've no idea if a previous owner has had it apart....from the tightness and 'cleanliness' of the threads I suspect not.
For other owners who may be experiencing a rattle, this is what I found...
Assuming they aren't loose (and the cause of the rattle - in my case they weren't), undo the four screws (M6 x 16 CSK - two each side) on the underside of the top middle part of the spoiler. This part can now pivot around the two guide pins at the lead edge of each side arm.
Pivot the top middle part of the spoiler upwards slightly and gently push it towards the front of the car (this is easier with two of you) - there are grooves in the sides of the blade that get deeper as you push it forwards so eventually it comes away from the rest of the assembly (put it to one side carefully)...
There should be a plastic washer over each guide pin (mine were there)...if they're not there you could get some lateral movement which might cause a rattle. The guide pin is an integral part of a plate that is screwed into a recess in the side arms of the rear spoiler assembly. Check the screws (M5 x 12 CSK) holding these plates are tight (mine were....in fact one screw is so tight I can't get it out at all...I have left it to soak in WD40 overnight in the hope I might get it undone tomorrow, I may also try heating slightly, there's no sign that they were held on with Loctite I suspect they were overtightened originally or its an effect of steel screws into brass threaded inserts).
Fixed to these plates should be two support brackets that form a mini-shelf either side for the top middle part of the spoiler (which is what the screws from underneath screwed into originally).
A pin screwed to these brackets slots into one of three holes (depending on spoiler angle) in the side plates. There is then an oval head M5 x 12 screw that screws from the other side of the side plate into a tapped hole in the support bracket (so to remove the support bracket completely you have to take the side plate off).
Now for the cause of my rattle....
When I took the blade out the remnants of some black cloth type tape (almost disintegrated away to nothing) were found on the guide pins. I believe this was fitted to take up some of the play between the pins and the slots in the blade.
I intend to heat shrink some rubber sleeving onto the guide pins instead.
When I looked at my support brackets there were only staying in position as a result of the pin on them sitting in the hole in the side plate - there were no screws (on either side) fixing the brackets to the side plates. The tapped threads in the brackets were still black (painted) which suggests to me these screws have never been fitted.
I think a combination of the degradation of the tape and the missing screws was causing my spoiler to rattle slightly...
If I can get the last screw out I will replace both missing screws....if not then I will use a M5 grub screw to effectively create two pins on one side and fit the missing screw on the other side. In combination with the rubber sleeving this should result in no more rattling at idle!
If anyone's interested (e.g. has the same symptoms) I will try to post some pictures later this week as I start to put it all back together.
Stuart
