OK.
I am new to this group and I asked a simple question, over 100 members looked at this post so far. I find it hard to believe that no one can help me here. I am sure that there are other boats with the same sun damage on the compass.
You reveal so few details about your compass problem that any reply could be far from useful help. But in any event, here goes. In fact, I just recently replaced/repaired my cockpit compass on my 1999 Bavaria 38, and also recently did so on a Cal20 that I own, and some years prior on my 1980 Pearson 30. On the Cal and the Pearson, the compass had been mounted on the bulkhead and sun damage had cracked and discolored the dome and card.
The Pearson had already been refitted for a wheel with a mounted binnacle compass so the bulkhead compass was no longer needed. I removed that bulkhead compass and replaced it with a cockpit speaker. For the Cal I went to West Marine, selected a Ritchie compass of about the same size and installed it in the same hole, although it did not fit precisely (they never do) so I had to modify the hole to make it work.
The compass on the 1999 Bavaria, which was installed on the binnacle, had developed a leak so the oil was disappearing and leaving a bubble at the top of the dome. That compass was a Suunto, a Finnish-made compass. There's no way that you're going to find one of those, or a repair kit for that compass, at West Marine, and b/c of the tight dimensions, etc., a substitute brand was not going to work out.
The only Suunto dealership in the USA is Andrews Compass Service in Mattapoisett, MA. I called him from Long Beach, CA, where the boat is, about the Suunto. Together we ascertained the model number which (of course) he does not stock. He contacts his supplier in the UK and they do not have one in stock either, but can get one from Finland in a few days. It's a discontinued model. He does, however, have the repair parts for my model in stock. To fix the compass, I need to buy the dome, the oil bowl, a couple of oil rings and some fresh oil, which is known as Ritchie oil (that you can get at West Marine). The only thing I don't need new is the compass card itself.
He then tells me (and this is illustrative of a compass repair) how to take the compass apart, remove the card from the old one and install it in the new housing, replace the o-rings, snap the housing together, and refill with the new oil. The only special tools I need is an abundance of patience and a
vacuum chamber to degas the oil before putting it into the housing. He did offer to fix it for me, however; for parts plus labor and shipping to MA and back.
A new one was > 3x the cost of the repair parts; his service repair was about 2x the cost of the repair parts only, so I just ordered the parts myself and dove in. God bless me for my patience and accessibility to a vacuum chamber that gets down to -24 in. It's fixed now and back on the boat, and all is well except that I do get a tiny bubble at the top of the dome occasionally which I called Mr. Magoo.
As far as explanation goes, he told me that the compass seal in the bowl failed because of overheating of the compass under the Sunbrella binnacle cover. The repeated over-expansion of the oil from temperature causes the bowl to leak. He suggested venting the binnacle cover at the sides near the top with "netting."