Fitted some new rear pads last weekend, haven’t used bike since, all seemed ok at the time.

Tried the brake lever last night (just in the shed), and although the brakes do appear to work (with back wheel lifted off ground and spun by hand), the lever hardly moves, like there is resistance, or the piston is stuck in the master cylinder. Tried bleeding with shimano tool, some air did come out, but not much.

Normally there’s a bit of free play in the lever, then it bites, kind of in a 2 stage movement.

Any ideas?