I have a 156 2 liter TS 2004 model.
I replaced the rear pads, as they needed to be replaced.
I made a tool to compress and turn the piston back, worked perfect. To do this I removed both calipers and did the work on the bench.
I then fitted the new pads and put the calipers back. I bled both rear calipers, but it had little pressure. I have only bled the rear calipers so far. Tested the car, and now I have no brakes at all, and the hand brake is also non existent. I had no problems before I fitted the new pads
I then removed the right rear caliper and had the brake pedal pushed down, and there were no pressure to push the piston forward, removed the fluid feeding line, and it too had almost no pressure, thus excluding faulty caliper (I hope). The brake pedal is hard, until car is started then it is pushed to (through) the floor with little effort.
It seems I have too little pressure in the system to push the calipers forward. It also appears as if I have no brakes from the front too!