Okay, chances are you have air trapped in the calipers. If you cannot get the bleeders loose, you will need to replace the calipers.
If you have ABS, the ABS needs to be bled as well. Below is the procedure but you need a scan tool to perform this operation.
Roy
ABS automated bleed procedure:
Bleeding the ABS system
Caution: Refer to brake fluid irritant caution in cautions and notice.
Notice: Refer to brake fluid effects on paint and electrical components notice in cautions and notices.
Perform a manual or pressure bleeding procedure. Refer to Hydraulic Brake System Bleeding (Manual) or Hydraulic Brake System Bleeding (Pressure) in Hydraulic Brakes. If the desired brake pedal height results are not achieved, perform the automated bleed procedure below. See: Hydraulic System, Brakes > Procedures > Hydraulic Brake System Bleeding (Manual) See: Hydraulic System, Brakes > Procedures > Hydraulic Brake System Bleeding (Pressure)
The procedure cycles the system valves and runs the pump in order to purge the air from the secondary circuits normally closed off during normal base brake operation and bleeding. The automated bleed procedure is recommended when air ingestion is suspected in the secondary circuits, or when the BPMV has been replaced.
Automated bleed procedure:
Notice: The Auto Bleed Procedure may be terminated at any time during the process by pressing the exit button. No further scan tool prompts pertaining to the Auto Bleed procedure will be given. After exiting the bleed procedure, relieve bleed pressure and disconnect bleed equipment per manufacturers instructions. Failure to properly relieve pressure may result in spilled brake fluid causing damage to components and painted surfaces.
1. Raise the vehicle on a suitable support. Refer to lifting and jacking the vehicle in general information.
2. Remove all four tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
3. Inspect the brake system for leaks and visual damage. Refer to Brake Fluid Loss or Symptoms - Hydraulic Brakes in Hydraulic Brakes. Repair or replace as needed. See: Hydraulic System, Brakes > Symptom Related Diagnostic Procedures
4. Inspect the battery state of charge. Refer to Battery Inspection/Test in Engine Electrical.
5. Install a scan tool.
6. Turn omn the ignition, with the engine off.
7. With the scan tool, establish communications with the EBCM. Select Special Functions. Select Automated Bleed from the Special Functions menu.
8. Bleed the base brake system. Refer to Hydraulic Brake System Bleeding (Manual) or Hydraulic Brake System Bleeding (Pressure) in Hydraulic Brakes.
9. Follow the scan tool directions until the desired brake pedal height is achieved.
10. If the bleed procedure is aborted, a malfunction exists. Perform the following steps before resuming the bleed procedure:
If a DTC is detected, refer to Diagnostic Trouble Code (DTC) List and diagnose the appropriate DTC. See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions
If the brake pedal feels spongy, perform the conventional brake bleed procedure again. Refer to Hydraulic Brake System Bleeding (Manual) or Hydraulic Brake System Bleeding (Pressure) in Hydraulic Brakes.
11. When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
12. Remove the scan tool.
13. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
14. Inspect the brake fluid level. Refer to Master Cylinder Reservoir Filling in Hydraulic Brakes.
15. Road test the vehicle while inspecting that the pedal remains high and firm. See: Brake Master Cylinder > Procedures > Master Cylinder Reservoir Filling
Saturday, June 16th, 2018 AT 3:42 PM
