If you ever develop a leak in the factory installed Danforth Cruiser compass, it must be replaced. It is not serviceable, and they are no longer available. A good direct replacement for this compass is the Ritchie F-82. It is fully serviceable and I prefer the flat card presentation. It will fit in the same hole, but the screw pattern is different.
This is from the Viking Compass website (http://www.vikingcompass.com/f-82.html):
The Cruiser compass line consisting of the following models A-154, C-351, C-351B is a flush mount compass originally made by the Aquameter Co.. When ITT purchased the Aquameter Co. the Cruiser was manufactured by Rule Industries and sold as part of the Danforth Compass line. The Cruiser compasses were discontinued in 2009. This compass was not a repairable compass, it was permanently "glued" together and cannot be disassembled. If your compass has an air bubble or the card is tilted at an angle the only choice is to replace the compass.
The recommended replacement compass for this model is the flush mounted Ritchie Voyager compass.
The F-82DR Voyager, is our custom made dual read version in the same compass body as the F-82, will have the same direct read type card that your Cruiser had. These compasses will fit in the same mounting hole as the Cruiser compass although it will be necessary to drill new screw holes for the Voyager compass. The F-82DR with its direct reading card is the obvious choice if your compass is mounted in an elevated console close to eye level.
The standard F-82 Voyager has a traditional flat dial which will work very well as a replacement for the Cruiser as long as the compass is mounted well below eye level. It will fit into the old mounting hole. You will have to drill new screw holes.
One problem with the original Mainship installation is the mounting surface is tilted about 15 degrees, which is the limit of the gimbals in these compasses, which causes the card to drag on the internal fixings. A shim is required to bring the mounting surface back to near zero. I made mine with a piece of 1" thick Starboard cut to a taper of about 10 degrees. Below are a few photo's of the finished job and new compass cover (V80-C) to protect it fro the elements.