I have an old 74 Blazer and I'm having problems with air in the rear brakes & brake lines. It's got a fairly new master (6 months) and doesn't appear to have any leaks anywhere. I've bled, vacuum bled & pressure bled the brakes. The air comes right back after a couple days. Pressure bleeding seems to work the best as the air is all the way up to the master (bubbles when you push the pedal). Has a good pedal after bleeding but slowly goes away. Is it time for another master? Any suggestions?
Thanks in advance.. B-C3