Ok for starters I have a 97 4x4 4.3l blazer (obviously). I have changed the RF caliper and a section of brake line along the DR frame rail as well as changed out the brake booster. I have bled the lines multiple times. The brake pedal will stop the truck but it goes almost to the floor to do so. It seems as if there is no pedal. The fluid in all the lines is clear as well as the fluid in the resivior. When bleeding the lines the pedal will be stiff with the engine off but as soon as I start it there is no pedal. Also the rubber piece inside my resivoir seems like its worn it dont seem to hold its original molded shape. Now heres my question... Could I possibly have air in the abs pump? Could my loss of pressure be due to the rubber piece inside the resivoir? I was told if I do have air the in the abs pump to remove the resivoir cap and I could cycle the key on wait two minutes and bleed the lines. cycle it off then back on and repeat the process. Eventually all the air in the pump will be released and I wouldnt need the use of the scan tool to remove it. I have read through every thread on here till Im blue in the face trying to find an answer. I have no leaks anywhere and all the bleeders at the wheels pour out a steady stream of fluid with no air.

 

id keep bleeding i changed my brake line running across the rear axle i had it running out clean no air then 100 bleeds later more air came out. i spent a solid 45 mins bleeding them by hand. if air got into the abs you might have to have it professionally bleed but not 100% sure. also when bleeding start from the furthest bleeder from the res to the closest