1996 Ford F150 V8 Four Wheel Drive Automatic 185000 miles
problems bleeding brakes. can bleed brakes hard while truck isnt running but as soon as i start it pedal goes soft New parts master cyclinder,and brake boster any ideas! also so you know im using brake bleeding pump with clear lines and no air is coming out.
Before bleeding system, remove all vacuum from power unit by depressing brake pedal several times. Bleed master cylinder first, followed in sequence by rear wheel cylinders, anti-lock system components (if equipped) and calipers. See BLEEDING SEQUENCE table.
Did you adjust the brake booster push rod when you put the new one on? If not do below
VACUUM POWER BOOSTER PUSH ROD
Push rod has an adjustment screw to maintain correct distance between booster push rod and master cylinder piston. If push rod is adjusted too long, it prevents master cylinder piston from completely releasing hydraulic pressure, causing brakes to drag. If push rod is adjusted too short, it causes excessive pedal travel and an undesirable groaning noise in booster area.
Remove master cylinder to access push rod. To check screw adjustment, fabricate a gauge. See Fig. 7. With engine running, place gauge against master cylinder mounting surface of booster. Adjust push rod screw by turning it until end of screw just touches inner edge of gauge slot.