You opened the brake system when you swapped the master cylinder.
Here’s the brake bleeding procedure when that’s done.
SPECIAL PROCEDURES
With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
If you have performed a brake master cylinder bench bleeding on this vehicle, or if you
disconnected the brake pipes from the master cylinder, you must perform the following steps:
Ensure that the brake master cylinder reservoir is full to the maximum-fill level.
With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
Reconnect the brake pipe to the master cylinder port and tighten securely.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
Loosen the same brake pipe to purge air from the open port of the master cylinder.
Tighten the brake pipe, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps until all air is purged from the same port of the master cylinder.
With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps.
After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.
disconnected the brake pipes from the master cylinder, you must perform the following steps:
If brake pedal height is not sufficient or it is suspected that air is trapped in the system, Using a scan tool, perform the antilock brake system automated bleeding procedure to remove any air that may have been trapped in the BPMV.
With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
Reconnect the brake pipe to the master cylinder port and tighten securely.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
Loosen the same brake pipe to purge air from the open port of the master cylinder.
Tighten the brake pipe, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps until all air is purged from the same port of the master cylinder.
With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps.
After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.
disconnected the brake pipes from the master cylinder, you must perform the following steps:
If brake pedal height is not sufficient or it is suspected that air is trapped in the system, Using a scan tool, perform the antilock brake system automated bleeding procedure to remove any air that may have been trapped in the BPMV.
Manual bleeding: Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve.
Submerge the open end of the transparent hose into a transparent container partially filled with GM approved or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure maintain steady pressure.
Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
Tighten the bleeder valve, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps 6-8 until all air is purged from the same wheel hydraulic circuit.
Repeat steps 4 - 9 for each caliper in sequence.
After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
Fill the brake master cylinder reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container.
If the brake pedal feels spongy, repeat the bleeding procedure again.
If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps:
Inspect the brake system for external leaks.
With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
If you have performed a brake master cylinder bench bleeding on this vehicle, or if you
Ensure that the brake master cylinder reservoir is full to the maximum-fill level.
With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
Reconnect the brake pipe to the master cylinder port and tighten securely.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure maintain steady pressure on the pedal.
Loosen the same brake pipe to purge air from the open port of the master cylinder.
Tighten the brake pipe, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps 18-22 until all air is purged from the same port of the master cylinder.
With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps.
After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
Pressure Bleeding : Fill the brake master cylinder reservoir to the maximum-fill level with GM approved or equivalent DOT-3 brake fluid.
Install the bleeder cap to the brake master cylinder reservoir.
Check the brake fluid level in the J 29532 , or equivalent.
Connect the J 29532 , or equivalent, to the master cylinder bleeder cap on fluid reservoir.
Charge the J 29532 , or equivalent, air tank to 175-205 kPa (25-30 psi).
Open the J 29532 , or equivalent, fluid tank valve to allow pressurized brake fluid to enter the brake system.
Wait approximately 30 seconds, then inspect the entire hydraulic brake system in order to ensure that there are no existing external brake fluid leaks. Any brake fluid leaks identified require repair prior to completing this procedure.
Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve.
Submerge the open end of the transparent hose into a transparent container partially filled with GM approved or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
Loosen the bleeder valve to purge air from the wheel hydraulic circuit. Allow fluid to flow until air bubbles stop flowing from the bleeder, then tighten the bleeder valve.
Repeat steps 34 -36 for each caliper in sequence.
After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
Close the J 29532 , or equivalent, fluid tank then disconnect the J 29532 , or equivalent, from the bleeder cap valve, then disconnect the J 29532 , or equivalent, from the J 35589-A .
Remove the bleeder cap from the brake master cylinder reservoir.
Fill the brake master cylinder reservoir to the maximum-fill level.
Slowly depress and release the brake pedal observe the feel of the brake pedal.
If the brake pedal feels spongy, perform the following steps:
Inspect the brake system for external leaks.
Perform the following steps to bleed the Antilock Brake System on vehicles without option JL4.
Connect a scan tool to the vehicle.
Start the engine and allow it to idle.
Depress the brake pedal firmly and maintain steady pressure on the pedal.
Using the scan tool, begin the automated bleed procedure.
Follow the instructions on the scan tool to complete the automated bleed procedure. Release the brake pedal between each test sequence.
Turn the ignition OFF and remove the scan tool from the vehicle.
Fill the brake master cylinder reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container.
Bleed the hydraulic brake system.
With the ignition OFF, apply the brakes 3–5 times, or until the brake pedal becomes firm, in order to deplete the brake booster power reserve.
Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
If the brake pedal feels spongy, repeat the automated bleeding procedure.
If the brake pedal still feels spongy after repeating the automated bleeding procedure inspect the brake system for external leaks.
Turn the ignition key ON, with the engine OFF; check to see if the brake system warning lamp remains illuminated.
If the brake system warning lamp remains illuminated, Do not allow the vehicle to be driven until it is diagnosed and repaired.
Drive the vehicle to exceed 8 mph/ 13 km to allow ABS initialization to occur. Observe brake pedal feel.
If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake pedal is obtained.
