Bleeding Modulator Assembly
CAUTION:
Perform manual bleeding procedure before bleeding modulator assembly. Follow exact order of modulator assembly bleeding procedure to ensure brake system is thoroughly and completely bled.
- Remove battery, battery tray and acid shield from vehicle. Connect battery to vehicle using jumper cables.
- Ensure all fluid lines are installed and correctly torqued. Bleed base brake system using standard manual procedure. See MANUAL BLEEDING .
- Connect scan tool to Data Link Connector (DLC), located behind panel fuse access cover on lower section of dash panel, left of steering column. See Fig 1
. Using scan tool, check CAB for stored fault messages. If stored fault messages exist, erase messages using scan tool.
WARNING: When bleeding modulator assembly, wear safety glasses. Clear bleed tube must be attached to bleed screw and submerged in clear container filled part way with clean brake fluid. Direct fluid away from painted surfaces. High-pressure brake fluid comes out when bleed screw is opened.
- Connect a clear bleed tube to primary check valve circuit bleed screw. See Fig 2 . Submerge other end of tube in clear container partially filled with clean brake fluid. Have assistant pump brake pedal several times and then hold pedal down, applying medium to heavy, constant pressure.
- Open primary check valve circuit bleed screw 1-2 turns. When brake pedal bottoms, tighten bleed screw. Release pedal. Repeat bleeding procedure until clear, air-free fluid comes out of primary check valve circuit. Tighten bleed screw to 80 INCH lbs. (9 N.m).
- Connect bleed tube to secondary check valve circuit bleed screw. Submerge other end of tube in clear container partially filled with clean brake fluid. Have assistant pump brake pedal several times and then hold pedal down, applying medium to heavy, constant pressure.
- Open secondary check valve circuit bleed screw 1-2 turns. When brake pedal bottoms, tighten bleed screw. Release pedal. Repeat bleeding procedure until clear, air-free fluid comes out of secondary check valve circuit. Tighten bleed screw to 80 INCH lbs. (9 N.m).
- Connect bleed tube to primary sump circuit bleed screw. Submerge other end of tube in clear container partially filled with clean brake fluid. Have assistant pump brake pedal several times and then hold pedal down, applying medium to heavy, constant pressure.
- Open primary sump circuit bleed screw 1-2 turns. Using scan tool, select bleed ABS hydraulic unit mode, then select primary circuit. Right front and left rear solenoids should alternately actuate for 5 seconds. Continue bleeding primary sump circuit until air-free fluid flow from bleed screw is attained or brake pedal bottoms.
- If air-free fluid flow is not attained when brake pedal bottoms, close bleed screw, and repeat steps 8) and 9) until air-free fluid flow is attained. Close and lightly tighten bleed screw. Release brake pedal. Remove bleed hose from primary sump bleed screw. Tighten primary sump bleed screw to 80 INCH lbs. (9 N.m).
- Connect bleed tube to primary accumulator circuit bleed screw. Submerge other end of tube in clear container partially filled with clean brake fluid. Have assistant pump brake pedal several times and then hold pedal down, applying medium to heavy, constant pressure.
- Using scan tool, select bleed ABS hydraulic unit mode, then select primary circuit valves. Right front and left rear solenoids should actuate for 5 seconds. Open primary accumulator circuit bleed screw 1-2 turns. Continue bleeding primary accumulator circuit until air-free fluid flow from bleed screw is attained or brake pedal bottoms.
- If air-free fluid flow is not attained when brake pedal bottoms, close bleed screw, and repeat steps 11) and 12) until air-free fluid flow is attained. Lightly tighten bleed screw. Release pedal. Pump brake pedal several times, then hold pedal down, applying medium to heavy, constant pressure.
- Without activating modulator solenoids, open primary accumulator circuit bleed screw one turn. Continue bleeding primary accumulator circuit until a clear, air-free fluid flow from bleed screw is attained or brake pedal bottoms.
- If air-free fluid flow is not attained when pedal bottoms, close bleed screw and repeat step 14) until a clear, air-free fluid flow is attained. Close and lightly tighten bleed screw. Release brake pedal. Remove bleed hose from bleed screw. Tighten primary accumulator circuit bleed screw to 80 INCH lbs. (9 N.m).
- Connect bleed tube to secondary sump circuit bleed screw. Submerge other end of tube in clear container partially filled with clean brake fluid. Have assistant pump brake pedal several times and then hold pedal down, applying medium to heavy, constant pressure.
- Open secondary sump circuit bleed screw 1-2 turns. Using scan tool, select bleed ABS hydraulic unit mode, then select secondary circuit valves. Left front and right rear solenoids should alternately actuate for 5 seconds. Continue bleeding secondary sump circuit until air-free fluid flow from bleed screw is attained or brake pedal bottoms.
- If air-free fluid flow is not attained when pedal bottoms, close bleed screw and repeat steps 16) and 17) until air-free fluid flow is attained. Close and lightly tighten bleed screw. Release brake pedal. Remove bleed hose from bleed screw. Tighten secondary sump circuit bleed screw to 80 INCH lbs. (9 N.m).
- Connect bleed tube to secondary accumulator circuit bleed screw. Submerge other end of tube in clear container partially filled with clean brake fluid. Have assistant pump brake pedal several times and then hold pedal down, applying medium to heavy, constant pressure.
- Using scan tool, select bleed ABS hydraulic unit mode, then select secondary circuit valves. Left front and right rear solenoids should actuate for 5 seconds. Open secondary accumulator circuit bleed screw 1-2 turns. Continue bleeding secondary accumulator circuit until air-free fluid flow from bleed screw is attained or brake pedal bottoms.
- If air-free fluid flow is not attained when brake pedal bottoms, close bleed screw, and repeat steps 19) and 20) until air-free fluid flow is attained. Lightly tighten bleed screw. Release brake pedal. Pump brake pedal several times, then hold pedal down, applying medium to heavy, constant pressure.
- Without activating modulator solenoids, open secondary accumulator circuit bleed screw at least one turn. Continue bleeding secondary accumulator circuit until a clear, air-free fluid flow from bleed screw is attained or brake pedal bottoms.
- If air-free fluid flow is not attained when pedal bottoms, close bleed screw and repeat step 22) until a clear, air-free fluid flow is attained. Close and lightly tighten bleed screw. Release brake pedal. Remove bleed hose from bleed screw. Tighten secondary accumulator circuit bleed screw to 80 INCH lbs. (9 N.m).