Bleeding a Single Hydraulic Brake Circuit
- 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.
- Place a clean shop cloth beneath the brake master cylinder to catch brake fluid spills.
- Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
- Fill the brake master cylinder reservoir to the maximum-full level with GM approved brake fluid from a clean, sealed brake fluid container. Add brake fluid as needed to ensure that the brake master cylinder reservoir remains at least half-full throughout the bleed procedure. The reservoir cap must be installed at all times except when filling the reservoir. Refer to Fluid and Lubricant Recommendations .
- Install a proper box-end wrench onto the wheel hydraulic circuit bleeder valve which has been serviced.
- 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 brake fluid from a clean, sealed brake fluid container.
- Have an assistant slowly press the brake pedal fully and maintain steady pressure on the pedal.
- 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 8- 10 until all air is purged from the wheel hydraulic circuit.
- After all air has been purged from the hydraulic circuit, tighten the bleeder valve and install the dust cap.
- Fill the brake master cylinder reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container.
- Slowly press and release the brake pedal. Observe the brake pedal feel.
- If the brake pedal feels spongy, perform Bleeding the Complete Brake Hydraulic System procedure:
- 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, refer to Diagnostic Starting Point - Vehicle
.NOTE: DO NOT allow the vehicle to be driven until it is diagnosed and repaired.