Use DOT3 or DOT4 brake fluid only!

This master cylinder was the first-ever of its kind to be fitted to any Volvo car.
Legislation that came into force in late 1967 in the USA demande that all cars be fitted with dual-circuit brakes. !
Hence this master cylinder,originally developed for Volvo by Wagner Brake in St. Louis, MO.
B18 dual-circuit USA 122S/1800S late 67 &1968
Please note that the reservoir is an aftermarket type that works well, but it is not Volvo genuine.
It is more square-shaped than the original.