Chevrolet Cobalt Service & Repair Manual: Component Replacement

Chevrolet Cobalt Service & Repair Manual / Steering & Suspension / Component Replacement

Anti-Lock Brake System Automated Bleed Procedure

1. Raise and support vehicle.
2. Remove all four wheel and tire assemblies.
3. Inspect brake system for leaks and damage.
4. Inspect battery state of charge.
5. Connect a suitably programmed scan tool to DLC (Data Link Connector).
6. Place ignition switch in On position with engine Off.
7. Using scan tool, establish communications with ABS system. Select Special Functions, then select Automated Bleed from Special Functions menu.
8. Follow instructions displayed on scan tool screen to bleed base brake system until desired brake pedal height is achieved.
9. If bleed procedure is aborted, a fault in system exists. Diagnose and repair indicated DTC(s).
10. When desired pedal height is achieved, press brake pedal to inspect for firmness.
11. Remove scan tool.
12. Install wheel and tire assemblies, then lower vehicle.
13. Torque lug nuts alternately and evenly in a criss cross pattern to 100 ft. lbs.
14. Check master cylinder level and fill with DOT 3 brake fluid if required.
15. Road test vehicle while inspecting that brake pedal remains high and firm.

Hydraulic Brake System Bleed Procedure

Manual Bleeding

1. Place a clean shop cloth beneath brake master cylinder to prevent brake fluid spills.
2. With ignition Off and brakes cool, deplete brake booster power reserve by applying brakes until brake pedal effort increases significantly.
3. If brake master cylinder bench bleeding has been performed on this vehicle or brake pipes were disconnected from master cylinder, proceed as follows:
  a. With rear brake line securely installed to master cylinder, loosen and separate front brake line from front port of brake master cylinder.
  b. Allow a small amount of brake fluid to gravity bleed from open port of master cylinder.
  c. Reconnect brake pipe to master cylinder port and tighten securely.
  d. Have an assistant slowly depress brake pedal fully and maintain steady pressure on pedal.
  e. Loosen same brake pipe to purge air from open port of master cylinder.
  f. Tighten brake pipe, then have assistant slowly release brake pedal.
  g. Wait 15 seconds, then repeat steps (a) through (f) until all air is purged from same port of master cylinder.
  h. With front brake pipe securely installed to master cylinder after all air has been purged from front port of master cylinder, loosen and separate rear brake pipe from master cylinder, then repeat steps (a) through (g).
  i. After completing final master cylinder port bleeding procedure, ensure that both of brake pipe to master cylinder fittings are securely tightened.
4. Fill brake master cylinder reservoir to proper level with DOT 3 brake fluid from a clean, sealed brake fluid container. Ensure that brake master cylinder reservoir remains at least half full during bleeding procedure. Add fluid as needed to maintain proper level. Clean outside of reservoir on and around reservoir cap prior to removing cap and diaphragm.
5. Install a suitable box end wrench onto right rear wheel hydraulic circuit bleeder valve.
6. Install a transparent hose over end of inner bleeder valve.
7. Submerge open end of transparent hose into a transparent container partially filled with DOT 3 brake fluid from a clean sealed brake fluid container.
8. Have an assistant slowly depress brake pedal fully and maintain steady pressure on pedal.
9. Loosen bleeder valve to purge air from wheel hydraulic circuit.
10. Tighten bleeder valve, then have assistant slowly release brake pedal.
11. Wait 15 seconds, then repeat steps 8 through 11 until all air is purged from wheel hydraulic circuit.
12. Securely tighten right rear wheel hydraulic circuit bleeder valve after all air has been purged from right rear hydraulic circuit.
13. Install a suitable box end wrench onto left front wheel hydraulic circuit bleeder valve (inboard). Install a transparent hose over end of bleeder valve, then repeat steps 8 through 11.
14. On models equipped w/2.0L TURBO (LNF) and SAAB Manual 5 Speed (MU3), install a proper box-end wrench onto left front wheel hydraulic circuit outboard bleeder valve. Install a transparent hose over end of bleeder valve, then repeat steps 8 through 11.
15. On all models, securely tighten left front wheel hydraulic circuit bleeder valve after all air has been purged from left front hydraulic circuit.
16. Install a proper box-end wrench onto left rear wheel hydraulic circuit bleeder valve. Install a transparent hose over end of bleeder valve, then repeat steps 8 through 11.
17. Securely tighten left rear wheel hydraulic circuit bleeder valve after all air has been purged from left rear hydraulic circuit.
18. Install a suitable box end wrench onto right front wheel hydraulic circuit bleeder valve (inboard). Install a transparent hose over end of bleeder valve, then repeat steps 8 through 11.
19. On models equipped w/2.0L TURBO (LNF) and SAAB Manual 5 Speed (MU3), install a proper box-end wrench onto right front wheel hydraulic circuit outboard bleeder valve. Install a transparent hose over end of bleeder valve, then repeat steps 8 through 11.
20. After completing final wheel hydraulic circuit bleeding procedure, ensure each of six wheel hydraulic circuit bleeder valves is properly tightened.
21. On all models, after completing final wheel hydraulic circuit bleeding procedure, ensure that each of four wheel hydraulic circuit bleeder valves are securely tightened.
22. Fill brake master cylinder reservoir to maximum fill level with DOT 3 brake fluid from a clean sealed brake fluid container.
23. Slowly depress and release brake pedal.
24. If brake pedal feels spongy, repeat bleeding procedure.
25. If brake pedal still feels spongy, brake hydraulic system will need to be pressure bleed as outlined under, "Pressure Bleed." If brake pedal is still spongy, hydraulic brake system will need to be diagnosed and repaired.
26. Turn ignition key On, with engine Off. Check if brake system warning lamp remains illuminated. If brake warning lamp remains On, brake hydraulic system will need to be diagnosed and repaired.

Pressure Bleed

1. Place a clean shop cloth beneath brake master cylinder to prevent brake fluid spills.
2. With ignition Off and brakes cool, apply brakes until brake pedal effort increases significantly in order to deplete brake booster power reserve.
3. If brake master cylinder bench bleeding has been performed on this vehicle or brake pipes were disconnected from master cylinder, proceed as follows:
  a. With rear brake line securely installed to master cylinder, loosen and separate front brake line from front port of brake master cylinder.
  b. Allow a small amount of brake fluid to gravity bleed from open port of master cylinder.
  c. Reconnect brake pipe to master cylinder port and tighten securely.
  d. Have an assistant slowly depress brake pedal fully and maintain steady pressure on pedal.
  e. Loosen same brake pipe to purge air from open port of master cylinder.
  f. Tighten brake pipe, then have assistant slowly release brake pedal.
  g. Wait 15 seconds, then repeat steps a through f until all air is purged from same port of master cylinder.
  h. With front brake pipe securely installed to master cylinder after all air has been purged from front port of master cylinder, loosen and separate rear brake pipe from master cylinder, then repeat steps a through g.
  i. After completing final master cylinder port bleeding procedure, ensure that both of brake pipe to master cylinder fittings are securely tightened.
4. Fill brake master cylinder reservoir to proper level with DOT 3 brake fluid from a clean, sealed brake fluid container. Ensure that brake master cylinder reservoir remains at least half full during bleeding procedure. Add fluid as needed to maintain proper level. Clean outside of reservoir on and around reservoir cap prior to removing cap and diaphragm.
5. Install tool No. j44894-A, or equivalent, to brake master cylinder reservoir.
6. Check brake fluid level in tool No. j29532, or equivalent. Add DOT 3 brake fluid from a clean sealed brake fluid container as required to bring level to approximately half full point.
7. Connect tool No. j29532 to tool No. j44894-A, or equivalents.
8. Charge tool No. j29532, or equivalent, air tank to 25 to 30 psi.
9. Open tool No. j29532, or equivalent, fluid tank valve to allow pressurized brake fluid to enter brake system.
10. Wait approximately 30 seconds, then inspect entire hydraulic brake system for external brake fluid leaks. If any external brake fluid leaks are present, brake hydraulic system will need to be diagnosed and repaired.
11. Install a suitable box end wrench onto right rear wheel hydraulic circuit bleeder valve.
12. Install a transparent hose over end of bleeder valve.
13. Submerge open end of transparent hose into a transparent container partially filled with DOT 3 brake fluid from a clean sealed brake fluid container
14. Loosen bleeder valve to purge air from wheel hydraulic circuit. Allow fluid to flow until air bubbles stop flowing from bleeder, then tighten bleeder valve.
15. Securely tighten right rear wheel hydraulic circuit bleeder valve after all air has been purged from right rear hydraulic circuit.
16. Install a suitable box-end wrench onto left front wheel hydraulic circuit bleeder valve (inboard). Install a transparent hose over end of bleeder valve, then repeat steps 13 and 14.
17. On models equipped w/2.0L TURBO (LNF) and SAAB Manual 5 Speed (MU3), install a proper box-end wrench onto left front wheel hydraulic circuit outboard bleeder valve. Install a transparent hose over end of bleeder valve, then repeat steps 13 and 14.
18. On all models, securely tighten left front wheel hydraulic circuit bleeder valve after all air has been purged from left front hydraulic circuit.
19. Install a suitable box end wrench onto left rear wheel hydraulic circuit bleeder valve. Install a transparent hose over end of bleeder valve, then repeat steps 13 and 14.
20. Securely tighten left rear wheel hydraulic circuit bleeder valve after all air has been purged from left rear hydraulic circuit.
21. Install a suitable box end wrench onto right front wheel hydraulic circuit bleeder valve (inboard). Install a transparent hose over end of bleeder valve, then repeat steps 13 and 14.
22. On models equipped w/2.0L TURBO (LNF) and SAAB Manual 5 Speed (MU3), install a proper box-end wrench onto right front wheel hydraulic circuit outboard bleeder valve. Install a transparent hose over end of bleeder valve, then repeat steps 13 and 14.
23. After completing final wheel hydraulic circuit bleeding procedure, ensure each of six wheel hydraulic circuit bleeder valves is properly tightened.
24. On all models, after completing final wheel hydraulic circuit bleeding procedure, ensure that each of four wheel hydraulic circuit bleeder valves are securely tightened.
25. Close tool No. j29532, or equivalent, fluid tank valve, then disconnect tool No. j29532 from J44894-A, or equivalents.
26. Remove tool No. j44894-A, or equivalent, from brake master cylinder reservoir.
27. Fill brake master cylinder reservoir to maximum fill level with DOT 3 brake fluid from a clean sealed brake fluid container.
28. Slowly depress and release brake pedal.
29. If brake pedal feels spongy, proceed as follows:
  a. Check brake hydraulic system for external leaks and repair system as required.
  b. Perform anti lock brake system bleed procedure as outlined under, "Anti-Lock Brake System Automated Bleed Procedure."
30. Turn ignition key On, with engine Off. Check if brake system warning lamp remains illuminated. If brake warning lamp remains On, brake hydraulic system will need to be diagnosed and repaired.

Steering Angle Sensor Centering

Centering of steering angle sensor may be required after certain service procedures are performed. Some of these procedures are steering gear replacement, steering column replacement, steering angle sensor replacement, intermediate shaft replacement, EBCM replacement or collision or physical damage.
1. Center steering wheel with wheels facing forward.
2. Perform special functions steering position sensor calibration, using a suitably programmed scan tool.

Brake Pressure Modulator Valve (BPMV)

To prevent equipment damage, never connect or disconnect wiring harness connection from the EBCM and EBTCM with the ignition switch in the ON position.
The area around the EBCM must be free from loose dirt to prevent contamination of dissembled ABS components.

Removal

1. Place ignition switch in Off position.
2. Remove cover from engine control module (ECM).
3. Clean EBCM to brake pressure modulator valve (BPMV) area of any accumulated dirt and foreign material.
4. Disconnect electrical connector from EBCM.
5. Disconnect and cap LR and RR brake line fittings from BPMV, Fig. 1.
6. Disconnect and cap LF and RF brake line fittings from BPMV, Fig. 2.
7. Disconnect and cap master cylinder primary and secondary brake line fitting from BPMV, Fig. 3.
8. Remove BPMV bolt, Fig. 4.
9. Carefully remove BPMV from BPMV bracket insulators by pulling straight upward, Fig. 5.
10. Remove EBCM, if required, as outlined in, "Electronic Brake Control Module (ECBM)."

Installation

1. Install EBCM, if required, as outlined in, "Electronic Brake Control Module (ECBM)."
2. Install BPMV to BPMV bracket until mounting pins are fully inserted in bracket insulators, Fig. 5.
3. Install BPMV bolt, then torque to 97 inch lbs., Fig. 4.
4. Connect master cylinder primary and secondary brake line fitting to BPMV, then torque to 14 ft. lbs., Fig. 3.
5. Connect LF and RF brake line fittings to BPMV, then torque to 14 ft. lbs., Fig. 2.
6. Connect LR and RR brake line fittings to BPMV, then torque to 14 ft. lbs., Fig. 1.
7. Connect electrical connector to EBCM.
8. Install cover to engine control module (ECM).
9. Program EBCM, using a suitably programmed scan tool.
10. Bleed hydraulic brake system as described under, "Hydraulic Brake System Bleed."
11. Perform Diagnostic System Check, using a suitably programmed scan tool.
12. Place ignition switch in Off position.
13. If pedal feels spongy, perform auto bleed procedure as described under, "Anti-Lock Brake System Automated Bleed Procedure."

Electronic Brake Control Module (ECBM)

To prevent equipment damage, never connect or disconnect wiring harness connection from the EBCM and EBTCM with the ignition switch in the ON position.
The area around the EBCM must be free from loose dirt to prevent contamination of dissembled ABS components.

Removal

1. Place ignition switch in Off position.
2. Remove cover from engine control module (ECM).
3. Clean EBCM to brake pressure modulator valve (BPMV) area of any accumulated dirt and foreign material.
4. Disconnect electrical connector from EBCM.
5. Remove EBCM bolts, Fig. 6.
6. Separate EBCM from BPMV by carefully pulling apart. Do not pry components apart, Fig. 7.
7. Remove EBCM O-ring seals and discard, Fig. 8.

Installation

1. Install new EBCM O-ring seals, Fig. 8.
2. Install EBCM to BPMV, Fig. 7.
3. Install EBCM bolts, then torque to 27 inch lbs., Fig. 6.
4. Connect electrical connector to EBCM.
5. Install cover to engine control module (ECM).
6. Perform EBCM programming and set up procedures, using a suitably programmed scan tool.

Electronic Traction Control Switch

Removal

1. Remove steering column opening filler assembly, pulling away from instrument panel retainer, then disconnect electrical connector for trunk release, Fig. 9.
2. Remove electronic traction control switch, pulling away from instrument panel retainer, then disconnect electrical connector, Fig. 10.

Installation

1. Connect and install electronic traction control switch, Fig. 10.
2. connect and install steering column opening filler assembly, Fig. 9.

Steering Angle Sensor

Removal

1. With vehicle wheels facing straight ahead, secure steering wheel utilizing steering column anti-rotation pin, steering column lock, or a strap to prevent rotation.
2. Remove intermediate steering shaft bolt, Fig. 11.
3. Disconnect intermediate steering shaft.
4. Disconnect and remove steering angle sensor.

Installation

1. Connect and install steering angle sensor.
2. Connect intermediate steering shaft.
3. Install intermediate steering shaft bolt, then torque to 25 ft. lbs., Fig. 11.
4. Unlock steering column.
5. Center steering angle sensor as outlined under "Steering Angle Sensor Centering."

Wheel Speed Sensor

Both front and rear wheel speed sensors and rings are integral with hub and bearing assemblies.

Removal

Front
1. Raise and support vehicle.
2. Remove wheel and tire assembly.
3. Insert a punch or drift in cooling fins of brake rotor and against brake caliper mounting bracket, Fig. 12.
4. on models equipped w/Brembo brake, have an assistant apply brakes.
5. On all models, remove wheel drive shaft nut from wheel drive shaft and discard.
6. Separate wheel drive shaft from steering knuckle, using tool No. j 28733-B, or equivalent, Fig. 13.
7. Remove brake rotor as follows:
  a. On models without Turbo, install a C clamp over body of brake caliper, with C clamp ends against rear of caliper body and outboard disc brake pad, compress piston into caliper bore just enough to allow caliper to slide away from rotor, Fig. 14.
  b. Remove C-clamp.
  c. On all models, remove brake caliper bracket bolts.
  d. Without disconnecting hydraulic brake flexible hose, remove brake caliper assembly and support from chassis with heavy mechanics wire, or equivalent.
  e. Remove and discard brake rotor retainers.
  f. Remove brake rotor, Fig. 15.
8. Disconnect speed sensor electrical connector.
9. Remove wheel bearing and hub retaining bolts.
10. Remove wheel bearing and hub assembly, Fig. 16.
Rear
1. Raise and support vehicle.
2. Remove wheel and tire assembly.
3. On models w/rear disc brakes, remove brake rotor as follows:
  a. Install a C clamp over body of brake caliper, with C clamp ends against rear of caliper body and outboard disc brake pad, compress piston into caliper bore .039 inch of travel only, Fig. 17.
  b. Remove C clamp from caliper.
  c. Remove caliper bracket bolts.
  d. Without disconnecting hydraulic brake flexible hose, remove brake caliper assembly and support from chassis with heavy mechanics wire, or equivalent.
  e. Remove brake rotor.
4. Disconnect electrical connector from wheel speed sensor.
5. Remove wheel bearing hub assembly mounting nuts, Fig. 18.
6. Remove wheel bearing hub assembly and disc brake backing plate from rear axle assembly.
7. On models w/rear drum brakes, remove brake drum as follows:
  a. Remove and discard brake drum retainers, Fig. 19.
  b. Remove brake drum.
8. Remove plug from drum brake actuator access hole in backing plate.
9. Support brake backing plate by actuator access hole from chassis with heavy mechanics wire, or equivalent, Fig. 20.
10. Disconnect wheel bearing hub electrical connector.
11. Remove wheel bearing hub assembly mounting nuts.
12. Remove wheel bearing hub assembly from rear axle assembly and brake backing plate, Fig. 21.

Installation

Front
1. Install wheel bearing and hub assembly, Fig. 16.
2. Install new wheel bearing and hub retaining bolts, then torque to 85 ft. lbs.
3. Connect speed sensor electrical connector.
4. Install brake rotor as follows:
  a. Thoroughly clean any rust or corrosion from mounting surface of brake rotor to wheel bearing and hub, using tool No. j 41013, or equivalent.
  b. Install brake rotor.
  c. Install brake caliper and brake caliper bracket as an assembly to suspension knuckle.
  d. Thoroughly clean any residue from bolt threads or mounting bracket bolt holes with denatured alcohol, or equivalent, and allow to dry.
  e. Apply thread locker, or equivalent, to bracket bolts, and allow cure approximately 10 minutes.
  f. Install two brake caliper bracket bolts, then torque to 85 ft. lbs. On models w/Turbo, torque to 96 ft. lbs.
5. Install front wheel drive shaft nut. Insert a drift on a flat-bladed tool into caliper and rotor to prevent rotor from turning.
6. on models equipped w/Brembo brake, have an assistant apply brakes.
7. On all models, install drive axle nut, then torque to 155 ft. lbs. On models w/Turbo, torque to 159 ft. lbs.
8. Install wheel and tire assembly, then torque lug nuts alternately and evenly in a criss cross pattern to 100 ft. lbs.
9. Lower vehicle.
Rear
1. On models w/rear drum brakes,Install wheel bearing hub assembly to rear axle assembly and brake backing plate, Fig. 21.
2. Install wheel bearing hub assembly mounting nuts, then torque nuts evenly to 33 ft. lbs. in a cross-pattern, plus additional 30 degrees.
3. Connect wheel bearing hub electrical connector.
4. Remove Support from brake backing, Fig. 20.
5. Install plug to drum brake actuator access hole in backing plate.
6. Install brake drum as follows:
  a. Install brake drum.
  b. Adjust drum brakes.
  c. Apply brakes two or three times to seat and center brake shoes on brake drum.
7. On models w/rear disc brakes,Install wheel bearing hub assembly and disc brake backing plate to rear axle assembly.
8. Install wheel bearing hub assembly mounting nuts, then torque nuts evenly to 33 ft. lbs. in a cross-pattern, plus additional 30 degrees, Fig. 18.
9. Connect electrical connector to wheel speed sensor.
10. Install brake rotor as follows:
  a. Thoroughly clean any rust or corrosion from mating surface and mounting surface of brake rotor, using tool No. j 41013, or equivalent.
  b. Install brake rotor.
  c. Install brake caliper assembly.
  d. Install caliper bracket bolts, then torque to 85 ft. lbs.
11. On all models, install wheel and tire assembly, then torque lug nuts alternately and evenly in a criss cross pattern to 100 ft. lbs.
12. Lower vehicle.

Yaw Sensor w/Lateral Accelerometer

Removal

1. Place ignition switch in Off position.
2. Remove right front seat as follows:
  a. Remove front seat assembly bolts.
  b. Disconnect drivers seat assembly.
  c. Remove right front seat, tilt seat forward to release front of seat tracks.
3. Remove right side front carpet retainer, Fig. 22.
4. Lift floor carpet to access yaw rate sensor.
5. Disconnect yaw rate sensor electrical connector.
6. Remove yaw rate sensor lateral accelerometer nuts, Fig. 23.
7. Remove yaw rate sensor.

Installation

1. Install yaw rate sensor.
2. Install yaw rate sensor lateral accelerometer nuts, then torque to 89 inch lbs., Fig. 23.
3. Connect yaw rate sensor electrical connector.
4. Position floor carpet.
5. Install right side front carpet retainer, Fig. 22.
6. Install right front seat as follows:
  a. Install right front seat.
  b. Connect drivers seat assembly.
  c. Install front seat assembly bolts, then torque to 22 ft. lbs.
7. Perform steering angle sensor calibration as described under, "Steering Angle Sensor Centering."
8. Perform system check vehicle, using a suitably programmed scan tool.

Fig. 1 Rear brake line fitting removal from BPMV

Fig. 2 Front brake line fitting removal from BPMV

Fig. 3 Master cylinder brake line fitting removal from BPMV

Fig. 4 BPMV bolt removal

Fig. 5 BPMV replacement

Fig. 6 EBCM bolt removal

Fig. 7 EBCM replacement

Fig. 8 EBCM O-ring seals replacement

Fig. 9 Steering column opening filler assembly replacement

Fig. 10 Electronic traction control switch removal

Fig. 11 Steering angle sensor replacement

Fig. 12 Drive shaft nut removal

Fig. 13 Drive shaft from knuckle removal

Fig. 14 Compress piston into caliper bore

Fig. 15 Brake rotor removal

Fig. 16 Wheel bearing hub assembly replace

Fig. 17 C clamp over body of brake caliper

Fig. 18 Rear disc wheel bearing hub assembly mounting nut removal

Fig. 19 Brake drum retainer removal

Fig. 20 Rear drum brake backing plate support

Fig. 21 Wheel bearing hub replacement

Fig. 22 Front carpet retainer removal

Fig. 23 Yaw rate sensor nut removal

    Steering & Suspension
    ...

    Description
    The VSES (Vehicle Stability Enhancement System) adds an additional level of vehicle control to the EBCM (Electronic Brake Control Module). The EBCM controls the system functions and det ...

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