C900 Headliner Repair
The first thing you need to do is to remove the headliner.
All of these either pull or unscrew. Keep track of which screws go where, as they can be different colors and lengths.
You need to remove anything that is holding it up!
With a hatchback C900, the headliner will come right out through the hatch.
For a sedan, the best way is to drop the rear seat and go out through the trunk.
Be careful when removing the shell. If yours is wet like mine, it bends very easily and may break apart. Two people are a must, but three would be even better.
Now you will really see if your sunroof is leaking or not. When I took my headliner out, it was very wet and needed to be dried before I could proceed with the job.