HOW TO: BMW Z3 (pre-facelift) 3rd brake light gasket replacement
A common complaint with leaks on the BMW Z3 seems to be in the boot and specifically around the third brake light - the root cause for this is because the gasket perishes over time.. it's a fairly cheap and straight forward process - but I couldn't find any guides for it so thought I'd throw one together as I've just done mine.
1 x BMW replacement gasket (p/n: 63 25 8 389 735)
1 x small flat blade screwdriver
1 x medium Phillips head screwdriver
1 x T-8 precision screwdriver
1 x cloth/rag
Open boot and remove black plastic protective cover - this just prise away from the body work (pull it gently):
The PCB which powers the individual brake lights is held in place by 3 x Phillips screws -take your Phillips screwdriver and remove these (highlighted in green circles in below pictures to show location):
Next you need to remove the 2 x T-8 screws which hold the black plastic back plate to the front red plastic lens - these are located either side of the black plastic back plate:
All fixings should now be removed (3 x Phillips screws and 2 x T-8 screws):
All that is now holding the front lens and black plastic back plate in place are the 4 black plastic compression clips - these are located here:
All you do now is work from one side to the other pressing them (gently!) together - once you release the last clip - the front red lens and the back black plastic piece separate:
Remove the old gasket from the red plastic lens and replace with the new gasket:
Comparison shot of old gasket (left) and new gasket (right):
Take your cloth/rag and clean the area around the third brake light to make sure it is free from dirt and grime and to ensure that it's dry:
Refitting is now just a reversal of removal - this can be quite fiddly though! - although once you have the red lens and black plastic backing clipped together its a fairly easy. The reason I suggested a small flat blade screwdriver above is because this will help enormously when it comes to clipping the black plastic clips onto the PCB.
Job done (and no more leaky boot!! ):
Hope this helps!!