Complete replacement 3/4" bore rear master cylinder assembly to fit Big Twin models with hydraulic rear drum brakes such as FL models from 1958 thru 1972 or FX models from 1971 thru 1972, and rear disc brake applications on FL and FX models from 1973 thru early 1979. The master cylinders are available in Ball Burnished finish as well as a beautiful show chrome finish.

Note: The new DOT 4 (as used in the late models Harley-Davidson) can be mixed with the old DOT 4 without any problem, even with the older DOT 3. The new DOT 4 CAN NOT BE MIXED WITH DOT 5. DOT 5 is a Silicon based fluid that has its own formula. This also means that DOT 4 can not be used in a system that has been on DOT 5 (and vice versa) unless the whole system has been taken apart and cleaned. It also needs new seals and cups before the DOT 4 can be used. Cleaning the parts with cloth or paper is also no option, the parts have to be very well cleaned with brake cleaner! (ZPN748043 or similar).