Morning Sergio,
Welcome to the Club where you'll find us a friendly bunch who will always try to go the extra mile to assist. You've already seen this by Thomas
@gangitano85 and Ed
@Edwrai jumping in offering advice.
The actual cause of the headlining dropping is due to the factory bonded foam to there fabric itself failing and there is no real tidy and permanent workaround. the reason this fails is due to age along with moisture content and the temperatures the roof of any vehicle is subjected to. You may have water ingress which will need resolving soonest otherwise you run the risk of a freshly reupholstered headlong dropping on a few years. The reason could also be the climate you live in but if the headlining has been fine for almost 20 years then there is no reason that it'll last and 20 if reup[holdstered correctly.
The adhesive used to adhere the foam backed headlining fabric doesn't fail and can be a pain to remove at the same time as being a very messy process.
Not that it'll help you but I was planning to offer headlining reupholstery as a member service to our wonderful community but have since decided against it, mainly due to having to correctly set up the service offering as a business. With my rock bottom pricing that I'd have to pay tax on as it'll of course be another income source which then wouldn't leave anything as pocket money which I could treat my family for all the time Ive spent in the garage away from them working on members headlining. After paying said taxes I would be left with nothing to show for the hours spent cleaning and preparing the headlining biscuit followed by the removal of the old and reinstallation of the new item. Raising pricing to account for this was absolutely out of the question.
That said I truly feel that this really is a DIY task. Many members have reupholstered their own headlining with spectacular results. Over PM I think I have also given Thomas
@gangitano85 plenty of pointers and should well be able to tackle his own headlining along with yours if you're able to organise a meet up on his way to Sicily.
If you're feeling confident to proceed by yourself then have a look online to understand whats involved and for inspiration. This
link, although isn't a perfect 'how to', will give you an idea of what is involved in the reupholstery process. Spend some time watching many YouTube clips as there are loads of them. Some of the clips you'll view are awful but they're worth the watch to it ensure you don't cut the corners like others have done before you.
For perfect results you must ensure that the headlining biscuit (compressed backing board) is immaculate before considering to add new adhesive. The adhesive used must be a High Temperature variant, if not then it will fail very quickly after a summer or 2.
I'm here to remotely assist when the time comes as I have done countless Saab 900 and Jaguar XJS headlining in the past. Ive also reupholstered 6 A2 headliners this past 18 months so quite seasoned in the process now.
Kind regards,
Tom