Re: Replaced brake pads - now soft pedal
My guess is that you pushed the pistons too far in and a seal contacted an area on the piston that was either dirty or corroded and allowed air to get past the seal.
The dirt or corrosion can be the result of a damaged boot, and this can lead to a damaged seal and leaks. keep your eyes open for any future leaks which can be contained behind the boot for a while. All seals leak, it's the amount that's the concern.
I did this once and I had to change the whole assembly, these days I only push the piston in enough to just get the new pads on.
If no oil has ever been added to the MC reservoir then pushing the pistons in the minimum amount will not lead to an overflow.
A daily driver is subject to more wear and tear all over than my garage princess, so a change in oil is recommended more often.