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?
Thanks in advance..