Hydraulic Brake System Bleeding Manual Bleeding

Bleeding is necessary if air has entered the hydraulic brake system.

You may need to bleed the system at all four wheels if a low fluid level has allowed air to enter the system or the brake pipes have been disconnectedat the master cylinder. If a pipe is disconnected at one wheel, then only bleed that wheel.

If you removed the master cylinder, you can reduce the time required to bleed the hydraulic system. Bleed the master cylinder before you reinstall the master cylinder on the vehicle.

If you replaced the Electric Hydraulic Control Unit (EHCU), refer to Electronic Brake Control Module Replacement in Antilock Brakes for the proper bleeding procedures.

Use the following procedure if you did not replace the EHCU.

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 master cylinder reservoirs with DOT 3 motor vehicle brake fluid.

Maintain the fluid level during the bleeding procedure.

2. Perform the following procedure if the master cylinder is suspected of having air contamination in the bore.

Bleed the master cylinder before bleeding any brake caliper.

2.1.	Disconnect the forward brake pipe connection at the master cylinder.

2.2.	Allow the brake fluid to flow from the connector port.

2.3.	Connect the brake pipe. Do not tighten the brake pipe.

2.4.	Apply the brake pedal slowly. Allow the air to bleed from the loose fitting.

2.5.	Tighten the fitting before releasing the pedal.

2.6.	Wait for 15 seconds.

2.7.	Repeat this sequence, including the 15-second wait, until all of the air is plunged from the bore.

2.8.	Repeat the procedure for the rear pipe after all of the air is removed from the forward connection.

3. Perform the following procedure in order to bleed the brake system:

3.1.	Bleed the right rear. Bleed both bleeders one at a time (for Dayton-Walther only).

3.2.	Bleed the left rear. Bleed both bleeders one at a time (for Dayton-Walther only).

3.3.	Bleed the right front.

3.4.	Bleed the left front.




4. Attach a hose to the caliper bleeder valve. Immerse the opposite end of the hose into a container partially filled with clean brake fluid.
5. Slowly apply the brake pedal one time and hold the brake pedal.
6. Loosen the bleeder valve in order to purge the air from the caliper.
7. Tighten the bleeder valve and slowly release the pedal.
8. Wait for 15 seconds.
9. Repeat the sequence, including the 15-second wait, until all of the air is purged from the caliper.
10. Continue steps 4-9 at each wheel until the brake system has been bled.
11. Inspect the brake pedal for sponginess.

Repeat the bleeding procedure if the brake is spongy.

Hydraulic Brake System Bleeding Pressure Bleeding

Bleeding is necessary if air has entered the hydraulic brake system.

It may be necessary to bleed the system at all four wheels if a low fluid level has allowed air to enter the system or the brake pipes have been disconnected at the master cylinder. If a pipe is disconnected at one wheel, then only bleed that wheel.

If you removed the master cylinder, you can reduce the time required to bleed the hydraulic system. Bleed the master cylinder before you reinstall the master cylinder on the vehicle.

If you replaced the Electric Hydraulic Control Unit (EHCU), refer to Electronic Brake Control Module Replacement in Antilock Brakes for the proper bleeding procedures.

Use the following procedure if you did not replace the EHCU.

Tools Required

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.

Use a diaphragm type pressure bleeder. The bleeder must have a rubber diaphragm between the air supply and the brake fluid in order to prevent the following from contaminating the hydraulic system:

1. Fill the pressure tank at least 2/3 full with brake fluid. Bleed the bleeder each time the fluid is added.
2. Charge the bleeder to 140-170 kPa (20-25 psi).
3. Install J 33855 on the master cylinder.
4. Connect the hose from the bleeder to the adapter.
5. Open the tank valve.
6. Bleed the brake system in the following sequence:

•	The right rear

•	The left rear

•	The right front

•	The left front




7. Attach the hose to the bleeder valve. Immerse the opposite end of the hose into a container that is partially filled with clean brake fluid.
8. Open the bleeder valve at lease 3/4 of a turn. Allow the fluid to flow until no air is found in the fluid.
9. Close the bleeder valve.
10. Repeat steps 6-8 at each wheel.
11. Inspect the brake pedal for sponginess.

Repeat the entire bleeding procedure if the brake pedal is spongy.




12. Disconnect the line from the bleeder adapter.
13. Remove the bleeder adapter J 33855 .
14. Fill the master cylinder to the proper fluid level. Refer to Master Cylinder Reservoir Filling .