After preparing my car for the MOT yesterday, I was amazed to find that I had no brakes - the pedal just went to the floor!
My first thought was to bleed them and sure enough, I bled out huge quantities of air from both front & rear circuits. After bleeding, the brakes are back to normal with a nice firm pedal again - no leaks of any kind either. The funny thing is, this is the first time I have had any problems with the brakes (on the road for 5 years now) and the brakes have been fine up to the time I put the car on SORN last October.

I have twin AP master cylinders on a bias bar, with Wilwood 4 pots all round - all components are now 5 years old but have only covered 20K miles in that time.

So where did all the air come from??

I'd imagine that a seal has hardened with lack of use. First time you pressed the brakes although the fluid didn't come out, air got back in when you released?

(I'm no expert, but my m/c was fine for the first 3 years, then the first time out of the garage after last winter, it leaked like a bugger. By the time I'd got new fluid / bled the system, it was fine again?).