Anyone bleed/flush the brakes on a 21+ yet?

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PsyZek

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I read through some older threads and requiring tools to cycle the ABS and such. Has anyone done a bleed job on these newer platforms that has any tips to share? I've got a 2022 and I'm coming up on two years and I'd like to flush the older fluid out.
 

Kpwweb

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Subbed. On my previous 2016 Tahoe I flushed the brakes twice without cycling the abs and they were fine.
 
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PsyZek

PsyZek

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Looks like its RR, LR, RF, LF, but you need to "Install a scan tool and select Deactivate Brake Boost System", which I'm unclear on. The manual uses a pressure system to flush the fluid, but I assume you can pump the pedal?



1. Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.

2. Fill the brake master cylinder reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container. Adhesives, Fluids, Lubricants, and Sealers

3. Disconnect brake fluid level sensor connector.

4. Install a scan tool and select Deactivate Brake Boost System.

5. Install the CH-44894-A Brake Bleeder Adapter or CH-35589-A Brake Bleeder Adapter to the brake master cylinder reservoir.

6. Check the brake fluid level in the CH-29532-A Pressure Brake Bleeder. Add GM approved brake fluid from a clean, sealed brake fluid container as necessary to bring the level to approximately the half-full point. Adhesives, Fluids, Lubricants, and Sealers

7. Connect the CH-29532-A Pressure Brake Bleeder, to the CH-44894-A Brake Bleeder Adapter or CH-35589-A Brake Bleeder Adapter.

8. Charge the CH-29532-A Pressure Brake Bleeder, air tank to 207 - 310 kPa (30 - 45 psi).

9. Open the CH-29532-A Pressure Brake Bleeder, fluid tank valve to allow pressurized brake fluid to enter the brake system.

10. Wait approximately 30 seconds, then inspect the entire hydraulic brake system in order to ensure that there are no existing external brake fluid leaks. Brake System External Leak Inspection Any brake fluid leaks identified require repair prior to completing this procedure.

11. Perform base brake bleed.

11.1. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve. 11.2. Install a transparent hose over the end of the bleeder valve.

11.3. Submerge the open end of the transparent hose into a transparent, graduated container partially filled with GM approved brake fluid from a clean, sealed brake fluid container. Note amount of fluid in the container. Adhesives, Fluids, Lubricants, and Sealers

11.4. Loosen the bleeder valve to purge air from the wheel hydraulic circuit. Allow at least 250 mL (8 fl oz) of fluid to flow into the container. Continue until air bubbles stop flowing from the bleeder, then close the bleeder valve.

11.5. With the right rear wheel hydraulic circuit bleeder valve closed, after all air has been purged from the right rear hydraulic circuit, install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.

11.6. Install a transparent hose over the end of the bleeder valve, then repeat steps 11.3- 11.4.

11.7. With the left rear wheel hydraulic circuit bleeder valve closed, after all air has been purged from the left rear hydraulic circuit, install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit inboard bleeder valve.

11.8. Install a transparent hose over the end of the bleeder valve.

11.9. Submerge the open end of the transparent hose into a transparent, graduated container partially filled with GM approved brake fluid from a clean, sealed brake fluid container. Note amount of fluid in the container. Adhesives, Fluids, Lubricants, and Sealers

11.10. Loosen the bleeder valve to purge air from the wheel hydraulic circuit. Allow at least 100 mL (3 fl oz) of fluid to flow into the container. Continue until air bubbles stop flowing from the bleeder, then close the bleeder valve.

11.11. With the right front wheel hydraulic circuit bleeder valve closed, after all air has been purged from the right front hydraulic circuit, install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit inboard bleeder valve.

11.12. Install a transparent hose over the end of the bleeder valve, then repeat steps 11.8- 11.10.

11.13. Repeat steps 11.7 - 11.10 for the outboard bleeder valve. Caution: Fastener Caution

11.14. After completing the final wheel hydraulic circuit bleeding procedure, ensure that front brake caliper bleeder valves and the rear bleeder valve are properly tightened to the necessary specification. Fastener Specifications

11.15. Close the CH-29532-A Pressure Brake Bleeder, fluid tank valve, then disconnect the CH-29532-A Pressure Brake Bleeder, from the CH-44894-A Brake Bleeder Adapter or CH[1]35589-A Brake Bleeder Adapter.

11.16. Remove the CH-44894-A Brake Bleeder Adapter or CH-35589-A Brake Bleeder Adapter from the brake master cylinder reservoir.

11.17. Fill the brake master cylinder reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container. Adhesives, Fluids, Lubricants, and Sealers

11.18. Inspect the brake system for external leaks. Brake System External Leak Inspection

12. Perform the Automated Bleed

12.1. Ensure the CH-44894-A Brake Bleeder Adapter or CH-35589-A Brake Bleeder Adapter is disconnected from the brake fluid reservoir. Install the brake fluid reservoir cap. Note: Ensure to use a battery charger and not a battery maintainer as a battery maintainer may not be able to maintain battery voltage during the automated brake bleed.

12.2. Install battery charger to ensure sufficient voltage.

12.3. Select Automated Brake Bleed within the scan tool and follow the instructions to complete the automated bleed. It is recommended to remain in the vehicle as brake pedal apply will be necessary.

12.4. Connect brake fluid level sensor connector.

13. A second base bleed is required to bleed any purged air from the brake master cylinder during the automated bleed. Repeat steps 5-11.

14. Ensure the CH-44894-A Brake Bleeder Adapter or CH-35589-A Brake Bleeder Adapter is disconnected from the brake fluid reservoir. Install the brake fluid reservoir cap.

15. Select Brake Hydraulic Test within the scan tool and follow the instructions to complete the hydraulic test. If the test passes, continue with next steps. If the test fails, inspect the brake system for external leaks, Brake System External Leak Inspection, and repeat steps 12-15. Note: If the Brake Hydraulics Test still fails after performing the Hydraulic Brake System Bleeding at least 3 times, performing the scan tool control function test Brake System Hydraulics Corner Test can be performed to help isolate the concern.

16. Turn the ignition ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated. Note: If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be driven until it is diagnosed and repaired.

17. If the brake system warning lamp remains illuminated, refer to Symptoms - Hydraulic Brakes.

18. Remove the scan tool from the vehicle.
 

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