I'm willing to bet a previous owner pulled it down to fix leaks. He/She did a crappy job of putting it back.

 

I had an issue with my 2004 Disco 2 (137k miles) where the headliner fabric came disconnected from the foam underneath in the area around the front moonroof trim. While the fabric has always sagged in many spots (since I bought the vehicle a few months ago) this is particularly bad because you can now see the foam underneath and stick your hand in between the foam and fabric.

I got some 3M 38808 spray headliner adhesive (about $17 at Autozone). I carefully sprayed the area between the sagging fabric and the foam. You want to put a cover on the seat underneath just in case you get some overspray or drips. I let the adhesive cure for about 10 min then using a small 4" paint roller, rolled the fabric tight to the foam. It stuck pretty quite well. All I had to do after that was tuck the ends of the fabric back under the rubber moonroof trim and I was done. Fabric still sags in many areas of the headliner but it looks much better and there is no more exposed foam backing. Hopefully this fix will last.

 

Why are Disco headliners such a problem?

They aren't!

Usually it is the previous owners not fixing the sunroof or other leaks or the roof overheating due to the solar gain heat, whatever.

Whether just painting or totally recovering, it will require the headliner removal and cleaning all the foam and adhesive off first.

 

This may work for some of you, fellows.
Get a syringe with a fatty enough tip to dispense plain 'school' white glue.

Inject small bits trough the fabric into the ceiling. Press with thumb that spot to spread the glue. Perhaps prop with a sponge for a while.

 

No, I must disagree about the cause. Over time the open-cell foam between the fabric and the fiberglass shell breaks down with age. It's not the adhesive, and a water infiltration is a secondary cause at most.

I painted mine several years ago. I stripped the fiberglass shell with denatured alcohol and primed it with Kilz. I then applied two coats of a good exterior latex from The Home Depot, mixed to match Bahama Beige. The pebbled finish of the fiberglass shell is perfect. Years later I still smile when I look at it and, IT WILL NEVER, EVER AGAIN SAG!

 

Update: I found after about a month that the headliner came loose again. Not nearly as bad as before however. I repeated the steps above and it is now fixed again. I suspect that the headliner adhesive is working fine but that the substrate beneath the fabric is essentially disintegrating and turning to powder and thus the adhesive comes off with it. I was a little more liberal with the adhesive this time so i'm hoping this will be the permanent fix (until i must up the courage to fully replace the headliner).

 

I actually agree with you Min, that is another reason for headliners to break down and delaminate. If the headliner is either wet or gets overheated also it will delaminate. Using the correct adhesive and material which is available online can solve the problem long term but the correct preparation of the substrate GRP is very important. My headliner was recovered by me 2-3 years ago and is fine now and I also replaced the 4# sunroof seals and marine silicon mastic front and back, it all appears OK at present. I also used thin multi layer insulation above the headliner to reduce the solar gain. Like all of the oldies we all fall apart sooner of later

PS: I can never figure why both a sunroof and AC is needed in any D2. In my newish D4 (LR4) I asked for the sunroofs to be omitted as they are the same type and a constant source of trouble.

 

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" . . . stuff they used to seal the cylinder head gaskets?" Head gaskets seal by equalized pressure against gasket, with NO sealant. I know some use sealant, but not needed.
LR uses crappy headliner sealant, and crappy upper dash hold down sealant, as on my Classic RR and my Discovery II, no doubt trying to save money.

 

I painted ours 5-6 years ago and it's still looking good. Dont miss it one bit.

 

I agree with you. I plan on keeping the LRDII long term and have no more intentions to drive around with saggy headliner. It just keeps failing not matter what you use. And going though the replacement hassle every 30-50k just to have fabric on your roof is a hassle. IMO not worth it. Painting this soon and will be glad to be done with it.