Replaced the front discs and pads on Ms Engineer’s BMW Mini on Saturday. Brakes now work fine, feel very powerful. However – if you press the pedal when the engine is idling, the pedal slowly depresses, not quite to the floor, but not far off. There are no leaks anywhere. I know it seems like there is some air in the system, but how? Any mechanics out there?

Assuming that you have put in the correct discs and pads, have you bled them?

You should not need to but I would start there if it were me assuming you have given a few strokes of the pedal to get them to self adjust first? My old 306 used to take 2 or 3 pumps to bring the pads in to meet the discs.

Edit: just re read op. Not sure this helps.

I am not a qualified mechanic btw just handy with a haynes manual and some tools.

A hose hasn’t split after taking the caliper off has it? Is the fluid level still the same?

Fluid level hasn’t changed, no split hoses that I can find.

forced the seal inside out in the Master cylinder when winding back the pistons ?

– allowing bypass under continued pressure on the brake ?

-not a mechanic either but have done similar on a clutch MC 🙁