fixing leaky xantia estate back door - Mr Smegma
I think most xantia estate owners have come across this at some stage. Because the back door is plastic citroen didn't bother stopping water getting in because it won't rust.

So the plastic membrane is relied upon for stopping the water coming into the car.

I removed it in order to replace the lock, but now I can't find an adhesive to glue it back on.

The clear plastic has a slightly waxy feel and nothing will stick to it. I reckon that the original stuff will do the job, but I don't know what it is.

Any ideas?
fixing leaky xantia estate back door - Dynamic Dave
Try Evo-Stik impact adhesive. Lightly smear both surfaces, wait 10 mins, then press together.