GM Repair Questions? Ask a Mechanic for Answers ASAP
You should start with a gravity bleed with the engine off . Because you have replaced the rear brake line you could start at the right rear and perform a conventional manual " pump " bleed . A good method if you like is to get a length of plastic tubing that will fit snuggly on the bleeder screw and insert it into a bottle with brake fluid in the bottom making sure the hose is submersed in fluid - open the bleeder screw . Fill the master cylinder and begin pumping ( this could take some time - be patient ) remember to keep the master cylinder topped up . Pump until there are no more bubbles . Repeat this procedure for the remaining 3 wheels .