1. Place master cylinder in soft-jaw vise, with front end tilted slightly down. DO NOT overtighten vise. Plug both outlet ports of master cylinder. Fill master cylinder reservoir. 2. Press and release piston about 1" (25 mm) several times. As air is bled from master cylinder, the primary piston will not travel the full 1" (25 mm) stroke. 3. Repeat previous step with front end of master cylinder tilted slightly up. Reposition master cylinder in vise to level position. Loosen front outlet plug and push piston into bore to expel air from cylinder. Tighten plug and allow piston to return to original position. Repeat procedure at rear outlet plug. 4. Fill reservoir and install master cylinder. DO NOT fully tighten brake lines at this time. Slowly press brake pedal to floor and hold. Tighten brake lines. Release brake pedal. Bleed brake system. See MANUAL BLEEDING or PRESSURE BLEEDING. MANUAL BLEEDING 1. Deplete vacuum reserve from power brake booster by depressing brake pedal several times with engine off. Fill master cylinder, and keep at least half full during bleeding procedure. If master cylinder is not known or suspected to have air in bore, go to step 4. If master cylinder is known or suspected to have air in bore, go to next step. 2. Disconnect forward brakeline fitting at master cylinder. Allow fluid to flow from fitting. Tighten fitting to specification. See TORQUE SPECIFICATIONS. Have an assistant depress brake pedal slowly and hold. Loosen forward fitting. Tighten fitting while pedal is still at floor. Release brake pedal slowly. Wait 15 seconds. 3. Repeat step 2, including 15 second wait, until fluid is clear and free of air bubbles. Repeat procedure at other (rearmost) brakeline fitting on master cylinder. Master cylinder is now bled. If wheel cylinders/calipers are not suspected to have air in them, it is not necessary to bleed them. 4. If wheel cylinders/calipers are known or suspected to have air in them, raise and support vehicle. Remove bleeder valve cap from right rear wheel. Place proper size box end wrench over bleeder valve. Attach one end of clear tube over valve and submerge other end in container partially filled with clean brake fluid. 5. Have an assistant depress brake pedal slowly and hold. Loosen bleeder valve to purge air from NOTE: To prevent air from entering brake system, bench bleed master cylinder before installing. NOTE: Air tends to cling to caliper walls. When bleeding vehicles with disc brakes, lightly tap caliper to help remove air. NOTE: Rapid pumping of brake pedal causes master cylinder secondary piston to move into a position that makes bleeding system difficult. NOTE: On vehicles with 4WAL, if brake pressure modulator valve was replaced, or is suspected to have air trapped inside, it must be bled next. See appropriate ANTI-LOCK article. Cylinder. Tighten bleeder valve and slowly release brake pedal. Wait 15 seconds. Repeat sequence, including 15 second wait, until all air is removed. 6. Remove tube and wrench. Repeat step 5 at left rear, right front, and left front wheels in this order. Fill master cylinder reservoir, and install cover. Ensure there is no sponginess in brake pedal and that BRAKE warning light is off.
Check power steering rewservoir, if it has bubles in ti, bleed air from PS system first. Check all fluid levels when done, Use ONLY DOT 3 brake fluid in master cylinder! Also try taking the truck to a gravel or grassy area, perform several quick stops this will excersize the ABS system, and sometimes brings the pedal hieght back up.
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Monday, November 23rd, 2009 AT 9:25 AM
