My 1994chevy 1500 2wd blew a rear brake line. Rusted out by fuel tank replaced rusty line from rear wheel abs controler below master cylinder to the rear brake hose. Refilled master cylinder tried to bleed brakes by pumping them and cracking the bleeder several times get no pressure just a small amount of fluid loosened line at master cylinder and fluid runs out but no pressure when the brakes are pumped up the.The rear brake reservoir was completly empty when i filled it. Do i need to bench Bleed the master cylinder? Fluid runs out of rear brake line port when the line is loose butt no pressure when pushing pedal.