Inflating headlining!!!

[timdaw]

I have a very annoying problem on my S3 B20. When I have the window open and speed exceeds about 75mph, the headlining 'inflates' and the bows become reversed, so I have the headlining almost on top of my head. When I slow down I can spring the bows back into place. Presumably this happens because the wool material is porous so the air passes through it.

Has anyone experienced this unusual problem? Any ideas for a fix? Replacing the bows with carbon fibre rods has been suggested. I preferably want to find a solution without having to take out the screens. Do you think it's possible to detach the sides and insert new bows? The tension of the headlining appears to be good.

Thank you.

[williamcorke]

I've never heard of this issue before.

Speculating... I wonder if, when the car was restored (assuming it was), thicker sound insulation was applied to the underside of the roof panel than the original material which is pretty thin on my S3. The springing on the bows could be sensitive to their installed height being a bit lower than the original position.

Alternatively, there might be new bows installed which are either too short or lack the metallurgical 'spring' required.

You clearly need to take things apart, and the good news is that, while that's a quite involved process, it will not require any glass to be removed.

[will]

Many years ago I had this problem on my Appia.
my wife sewed it up but it looked a bit naff.
It was only fixed when the car was restored  and had new headlining fitted.
The headlining is held place by rods in a loop in the headlining fabric.
On the Appia the fabric and stiching was rotten so it was loose.
On the B20 I supplied a local trimmer with the rods and the old headlining
it was not that difficult to fit as it was grey fabric  not difficult to find.
The bad news is you will need to remove the windscreen and back window.

[timdaw]

Thanks for the replies. The headling is a recent replacement and I don't think the insulation is thick. Are the bows shaped at the ends?

[williamcorke]

The headlining is out of my S3, I'll photograph the bows and post a picture here.

Will and I disagree about the screens! You will have to remove the internal trim around the screens certainly, but, in my opinion, not the screens themselves. And the full length side trims that pass under the interior lights of course... which means side panels must come out too. Quite a lot.

[williamcorke]

I hope these are helpful. All the bows (the originals I'm sure, as is the headlining) seem to have the same angle of bend on the end but be pretty straight apart from the ends - when at rest at least.

[timdaw]

That's very helpful thank you very much William. I didn't realise that they are flat sections. What do they fix into at each end? Presumably it's a channel, but does it have cutaways or ports to accept the bows? Do you think that a round section replacement would be able to 'lock into' the side channels?
I'm a bit worried that if I use carbon or fibreglass it may pull the sides into a funny shape.
AS you say, I was hoping that removing the side trims and the window surrounds would enable me to access them without taking out the screens.

[williamcorke]

Here are the fixings:
- slot for bow ends
- hooks for the front fixing strip from side to side

You can see the indentation from the bow in the sound-deadening material, which is thin - hence my though about thicker replacement material possibly contributing to your inflation/collapse problem (more likely caused by low pressure?).

I suspect your bows are fine, but you could make new ones by cutting spring steel if not. I can provide a thickness measurement if you take that path.

[williamcorke]

I should perhaps have said before that you install the liner from the back forwards (as the hooks at the front suggest or rather instruct, as that's where you adjust the tension front to back). Opposite applies to disassembly of course...

[timdaw]

Many thanks again for the really very helpful photographs William. I see what you mean about the thickness of the soundproofing. It doesn't look like carbon or fibreglass replacements would be an option because of the slots to anchor the bows. I really don't want to remove the screens, but this is looking more and more like a very involved (and very expensive) operation, on a car that has been completely restored, including new headlining, less than 1000 miles ago!

[chriswgawne]

I dont  think the glass has to be removed as both the front and rear screens have inner painted surrounds dont they?
And there are removeable fabric covered aluminium side trim panels?
Chris

[williamcorke]

I agree Chris, the screens don't have to come out.

Tim, this shouldn't be an expensive operation if you're doing it yourself, and with only 1,000 miles since the restoration it's perhaps sensible to think of this as a 'snagging' task.

The front inner screen surround is painted but on my car and most S3s I've seen the rear is covered in the same cloth as the headlining - however I think that on Tim's car it's painted (Tim, is your car 2857?). That doesn't make any difference to the process of course, and having been recently restored the fixing screws should be easily removed, which is a major head start.

[timdaw]

Thanks again Chris and William for the very useful advice. In the meantime the front screen shattered (!), and I have the front inside screen surround off whilst removing the broken glass. If the back is the same then the screens don't need to come out, just all the surrounds removed. The tension of the headlining does seem fine though, and I don't think it would be possible to make it much tighter. So I'm more inclined to think it needs stronger bows. If they were round wires it would be easy to replace with fibreglass or carbon, but as they are flat that is much more complicated! ONce I expose a bit of it I can then see if the roof insulation is too thick.

[Niels Jonassen]

The original bows are made of spring steel. They hold the material if they have the right size. You need not remove glass to fit new head lining on a 3rd series. However, if the front window glass is broken you have to remove the entire frame in which it is mounted. The frame is screwed onto the a pillars. It is not very difficult.

[timdaw]

Thank you Niels. I removed the old glass and cleaned out the surround ready for the new screen.