After replacing rear brake shoes the pedal is hard at first, then falls to the floor

Good afternoon.

When you adjusted the rear brakes, you should have adjusted them until there was a good drag on the tire. Not just until you hear them at the drum. They may be too loose.

If it still goes to the floor, then you may have a failed master cylinder from pumping the brake pedal. This does happen after replacing brake parts if you are not careful pumping up the brake pedal.

Roy

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

I adjusted them with the tire off and they only barely spin to about two to three revolutions. With the tire on they spin longer of course.

However, I got under there and bled the wheel cylinders for the heck of it. The driver side wheel cylinder shot out a lot of air and then the fluid became steady. That seemed to fix it, now I can brake more steadily now, but I can just *barely* feel the same thing happen, maybe for just a second when pressing the brakes. Or maybe it is just me.

The real question is, now why would there just magically be air in my brake lines?

It is hard to say. The wheel cylinder may have been moved around enough to pull in some air. You should remove the top cover of the master when you do the brakes as well to allow for movement of the fluid.

Roy

Do drum brakes not adjust themselves? After the initial adjustment I thought they would periodically adjust themselves. I have not had any calls from the customer about having issues.

You need to set the initial adjustment first. Then through the process of backing up and moving forward, the self-adjusters will operate.

Roy