The master cylinders are readily available as they are used on more modern vehicles.
https://www.amazon.ca/gp/product/B001PYNSZO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Dorman M2842
INTERNATIONAL S1723 1980-1983
INTERNATIONAL S1724 1980-1983
INTERNATIONAL S1754 1981-1983
INTERNATIONAL S1823 1980-1982
INTERNATIONAL S1824 1980
INTERNATIONAL S1853 1981-1982
INTERNATIONAL S1854 1981-1982
INTERNATIONAL S1924 1980-1982
INTERNATIONAL S1925 1980-1982
INTERNATIONAL S1954 1981-1983
INTERNATIONAL S1955 1981-1983
INTERNATIONAL S2524 1980-1982
INTERNATIONAL S2554 1982-1983
Oreillys nmc11251
Ford CF6000: 1986, 1987, 1988, 1989, 1990
Ford CF7000: 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
The reservoir extender off of the old master cylinder has to be swapped over to the new one.
I replaced mine a month ago.