Manual and Pressure Bleeding Procedures
If air has entered the hydraulic brake system, bleed the system. You may need to bleed the hydraulic brake system at all four wheels due to one of the following conditions:- Air entered the system due to a low fluid level.
- The brake pipes have been disconnected at the master cylinder.
- The brake pipes have been disconnected at the combination valve.
If a pipe is disconnected at one wheel, then only bleed that wheel.
If the master cylinder has been removed, bleed the master cylinder before installing it on the vehicle in order to reduce the time required to bleed the system. Refer to Master Cylinder Bench Bleeding.
If the Brake Pressure Modulator Valve (BPMV) has been replaced or has air trapped it, refer to the Automated Bleed Procedure.
Manual Bleeding
- Tools Required
- J28434 Wheel Cylinder Bleeder Wrench
Notice: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers, and fender covers to prevent brake fluid from contacting these areas. Always re-seal and wipe off brake fluid containers to prevent spills.
1. Apply the brakes several times with the ignition OFF in order to relieve the brake vacuum reserve.
2. Fill the master cylinder reservoir.
3. Maintain the fluid level during bleeding.
4. If the master cylinder has air in the bore, bleed the master cylinder using the following procedure:
4.1. Disconnect the forward brake pipe connector at the master cylinder.
4.2. Allow the brake fluid to flow from the connector port.
4.3. Connect the brake pipe connector. Do not tighten the brake pipe connector.
4.4. Slowly apply the brake pedal and allow the air to bleed from the loose connector.
4.5. Tighten the connector before releasing the brake pedal.
4.6. Wait 15 seconds.
4.7. Repeat this sequence, including the 15-second wait, until all air is purged from the master cylinder bore.
4.8. Repeat this procedure for the rear brake pipe after you purge all the air from the forward pipe connection.
5. If the Brake Pressure Modulator Valve of the 4WAL system is replaced or if you suspect that air is trapped inside, bleed the BPMV next. Refer to the Automated Bleed Procedure.
6. Bleed each wheel cylinder in the following sequence:
6.1. Right rear wheel cylinder.
6.2. Left rear wheel cylinder.
6.3. Right front wheel caliper.
6.4. Left front wheel caliper.
7. Attach a hose on the wheel cylinder or caliper bleeder valve.
8. Loosen the bleeder valve 1/2 to 1 turn.
9. Immerse the opposite end of the hose into a container partially filled with clean brake fluid.
10. Slowly apply the brake pedal one time and hold.
11. Tighten the bleeder valve and slowly release the brake pedal.
12. Wait 15 seconds. Check the master cylinder fluid level.
13. Repeat this sequence, including the 15-second wait, until one pint of fluid has been bled and no air is seen in the fluid.
Notice: Refer to Fastener Notice in Service Precautions.
14. Tighten the bleeder valve.
- Tighten the bleeder valve to 7 Nm (62 inch lbs.).
15. Repeat steps seven through fourteen at each wheel until the brake system is bled.
16. Use a Scan Tool to perform four4WAL function tests.
17. Re-bleed each wheel circuit.
18. Fill the master cylinder to the proper level. Refer Master Cylinder Reservoir Filling.
19. Check the brake pedal for sponginess, and check the brake warning lamp for an indication of unbalanced pressure. Repeat the bleeding procedure in order to correct either of these conditions.
Pressure Bleeding
Use a diaphragm-type pressure bleeder. The pressure bleeder must have a rubber diaphragm between the air supply and the brake fluid. This prevents air, moisture, oil and other contaminants from entering the brake hydraulic system.
- Tools Required
- J41618 Brake Bleeder Adapter Set
- J39177Combination Valve Pressure Bleeding Tool
- J29567 Brake Pressure Bleeder
Notice: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers, and fender covers to prevent brake fluid from contacting these areas. Always re-seal and wipe off brake fluid containers to prevent spills.
1. Fill the pressure tank at least 2/3 full of brake fluid.
2. Bleed the J29567 each time fluid is added.
3. Charge the J29567 with 140 - 170 kPa (20 - 25 psi) air pressure.
4. Use the J39177 in order to depress and hold the valve stem on the combination valve on the BPMV assembly.
5. Install the J29567 and the J41618.
6. If the BPMV of the 4WAL system is replaced, or if you suspect that air is trapped inside, bleed the BPMV first. Refer to Refer to Automated Bleed Procedure.
7. Connect the hose from the bleeder to the adapter at the master cylinder.
8. Open the tank valve.
9. Attach a hose to the bleeder valve at the right rear wheel.
10. Immerse the opposite end of the hose into a container partially filled with clean brake fluid.
11. Open the bleeder valve at least 1/2 to 1 turn. Allow the fluid to flow until you see no air in the fluid.
Notice: Refer to Fastener Notice in Service Precautions.
12. Tighten the bleeder valve.
- Tighten the wheel cylinder or caliper bleeder valve to 7 Nm (62 inch lbs.).
13. Bleed each wheel cylinder in the following sequence:
13.1. Right rear wheel cylinder.
13.2. Left rear wheel cylinder.
13.3. Right front wheel caliper.
13.4. Left front wheel caliper.
14. Remove the J39177.
15. Use a Scan Tool to perform four 4WAL function tests.
16. Re-bleed each wheel circuit.
17. Check the brake pedal for sponginess and check the brake warning lamp for an indication of unbalanced pressure. Repeat the bleeding procedure in order to correct either of these conditions.
18. Turn off the valve on the bleeder.
19. Disconnect the hose from the J41618.
20. Remove the J41618.
21. Fill the master cylinder to the proper level.
22. Check the feel of the brake pedal.