Kev...as Bill(red58) mentions the glass may be at fault.Try a 'dry' run without the rubber as Bill suggests,this should show up any anomalies.
These screens are formed on a buck,the glass is heated and sags into the finished shape,it could be you have a bad 'un!(It
does happen I'm afraid!)
Another possibility is the glass isn't centred properly in the aperature. Are you starting the fitting from the centre?
If you start the 'string in' from the side it will 'kick' the glass over to one side,giving the problem you describe.
We've had similar problems with Scania 4 series trucks which have heavy curves at each end.
I hope this gives you some pointers.I DO hope it's the latter problem!
Good luck.
Jock
