I drove my Disco II to work this morning after last night's heavy rain with no issue, but when I took the truck to lunch, I noticed my seat was wet. Once I began moving, a huge flood of water poured on me from above. I found the water was coming from where the seat belt retracts. After feeling around, the headliner along the rear driver's side door is soaked. Where could water be getting in? How should I proceed? Thank you!

 

Almost surely the sun/moon roof seals; there is a drain on them that can become clogged, too.

 

I've done some reading and it appears that the front sunroof drains through the A pillar. My leak is coming around the rear driver's side door. Does the rear sunroof drain through here?

 

I have a donor rover semi-apart right now; I'll give it a look see and let you know this evening.

Edit: sorry I have not finished. The B pillar is hollow but encased so you can access it. I haven't gotten the headliner out yet. Sounds like you figured it out though. Please post pictures.

 

Yep, a common fault with D2 sunroofs, it comes to everyone who waits - sooner or later.

Can be many entry points, the exit point doesn't denote the ingress point, but best remove the headliner, sunroof(s) and set in new seals at the same time check the roof drains are clear and the plastic well not broken.

There's an article and fix in LRO April 2014 dedicated to sunroofs.

You can also get leaks around the front screen which is hot wire 'glued' into place.

 

just done this. The drain pipe was broken on mine. Still have a slight leak, which i think is now the seals, but check the outlet pipes first.

Enjoy taking the headlining down/out.....