have a 67 chevelle malibu. power breaks and drums in all four. Lately as i get going, when i come to a full stop i can hear not a grinding but more like springs being compressed kind of sound. As i let go of the break pedal, it feels as if the pads are stuck and not releasing right away. It takes a while for them to release. I have good pads left in all four. Don't know if this is a master cylinder or power boost problem?

Don't know if this is a master cylinder or power boost problem?

I don't think it's either. Have you pulled the drums to see if there are any loose or broken springs?

I don't think it's either. Have you pulled the drums to see if there are any loose or broken springs?

I agree. It may even be that the return springs are simply tired. You might want to look into a couple of new hardware kits.