What fluid is in it now? If it isn't DOT 5, you'll have to flush the entire system with alcohol before filling with DOT 5.
DOT 3, DOT 4, and DOT 5.1 are compatible with each other.
DOT 5 is 100% silicone and cannot be mixed with the others. If you have anti-lock brakes you cannot use DOT 5.
Are you drag racing it or auto-crossing in it? If not you really won't have a need for DOT 5.
