Are there any common areas for water to get in? I'm finding that when I wash the car, they fill up. I tried adding a tiny bead of clear silicone around the edge of the lense and the casing around the top, so I don't believe it's getting in there.

 

Had same with my 98 car.

First off, remove the lights, remove all traces of old sealant, (scrape, white spirit), and inspect fronts and rears minutely. To clean interior, I used a piece of semi=rigid copper wire like that found inside house wiring, with a loop at one end and kitchen roll through the loop.

I found a small crack in the rear, and one in the front. The front one I welded with plastic weld, the rear I filled with carafax.

Then re-seat the lights in this stuff:http://www.caravan-components.co.uk/...-in-400ml-Tube

Non-setting mastic, it's the proper stuff.

Getting them dry to start with is hard, mine spent two days off and once the water had been soaked out, the stood in the sunshine to allow any residual moisture to evaporate.

 

Cheers for the info. I'll get them off again and take a look.

 

Found it! After spraying the edges of the lenses carefully, I found that they were sealed nicely with the silicone.

It was actually the foam gaskets that the clusters push against. Just sprayed the hose on the back window, and it just streamed in, then dripped in through the middle bulbs.

I'm looking at calling Subaru to get some replacement gaskets. They seem impossible to find online in the UK. If anyone knows where I could order them..

 

For reference, this is one of the gaskets. Completely shot at, and missing the section from the most important part at the top seam.