Hard to find. This place shows a 1984 C20.
ER472K Front Left
Absco Disc Brake Caliper ER472K
Disc Brake Caliper
Notes:
Using ABSCO disc reference no: D52 WITH CALIPER CASTING #(S)
K18007152 K18007153 REMAN SEMI-LOADED CALIPER
https://dpars.com/fr/Catalog/1984/Ch...-Brake-Caliper