There are 2 different companies that make the valves. 70-71 were made by Kelsey Hayes. 72- 74 were made by Weatherhead. That is what you are picturing above. What could be leaking. They sell rebuild kits and the are simple.
1970 - 1976 Mopar Combination Brake Valve Seal Kit | Muscle Car Research LLC
1970 - 1976 Mopar Combination Valve Rebuild | Muscle Car Research LLC
