Pre Combustion Chamber Leak

-I have a 90 300d 2.5 turbo. The number 2 cylinder pre chamber is leaking compression by it. I can see it comeing out the top of around the prechamber special nut on the out side of it where theres that lil gap. -Has any body had this happen and how did u fix it? -I see i need a special tool to get the top nut out, is there other special tools i will need? -What kind of damage may have this caused to the cylinder head? Jerritt