2 people required ideally. get some one to push down on the brake pedal. go to the rear brake drum or calliper there u will see a nut which should have a rubber fitting on top (dust cap) remove this and open the not slowly. then u will hear the air release followed by brake fluid. close it again. get the person to pump the brake again and keeping the foot on the pedal. again open the bleed nut once u have a constant fluid flow close it then job done. u may need to do other wheels depending on if air has entered further into the system. also make sure there is enough fluid in the brake resovouir
here is a youtube link it may help
http://www.youtube.com/watch?v=Hf1iPbeg778
kash, January 2013