72 cuda disc/ drum issue

[Joemoy29]

so I am finally getting the car ready to drive. The brake system was complete when I bought the car. So I changed all the lines. Did not change the proportioning valve, master cyl or read drum cyl. I bled the brakes and got a great pedal. Two days after it was soft and would get solid after a couple pumps.

This is my first manual brake car lol but I am assuming it is not normal. Couple other things I noticed was I don’t have a “metering block”. It’s just the proportioning block that the two lines from master cyl go into. Could this be the issue or is it prob a leak?

Thank you for the help

 

[moparleo]

If it pumps up, it has air in the system. How old are the calipers and wheel cylinders ? Is this the original brake system ? Brake fluid absorbs water and it settles at the low spots, the cylinders and calipers. That's is where the rust forms. Tell us everything that you did to the brake system so we can know better what you might have missed.

 

[Joemoy29]

I found the problem. The master cyl is leaking at the firewall. The only isssue is I don’t know what one to order. The car has manual brakes with front disc and 11” rear drums. I cannot find one listed for front disc manual brakes