you have to release the bleed nipple then with a small 6/7mm square bar push into the slot's on the piston and turn the piston and it winds in you can not just push the piston it has to turn (if you have a pet shop handy get 3ft of tube for fish tank pumps attach to the nipple 1st then wind piston back just save's time stops air getting into the braking system)
titch, June 2010