HHR L4-2.4L (2010)
Brake Master Cylinder: Procedures
Master Cylinder Bench Bleeding
Master Cylinder Bench Bleeding
Warning: Refer to Brake Fluid Irritant Warning (See: Service Precautions/Technician Safety Information/Brake Fluid Irritant Warning).
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution (See: Service Precautions/Vehicle Damage Warnings).
1. Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.
2. Remove the master cylinder reservoir cap and diaphragm.
3. Install suitable fittings to the master cylinder ports that match the type of flare seat required and also provide for hose attachment.
4. Install transparent hoses to the fittings installed to the master cylinder ports, then route the hoses into the master cylinder reservoir.
5. Fill the master cylinder reservoir to at least the half-way point with GM approved brake fluid from a clean, sealed brake fluid container. Refer to
Master Cylinder Reservoir Filling (See: Master Cylinder Reservoir Filling).
6. Ensure that the ends of the transparent hoses running into the master cylinder reservoir are fully submerged in the brake fluid.
7. Using a smooth, round-ended tool, depress and release the primary piston as far as it will travel, a depth of about 25 mm (1 in), several times.
Observe the flow of fluid coming from the ports.
As air is bled from the primary and secondary pistons, the effort required to depress the primary piston will increase and the amount of travel will
decrease.
8. Continue to depress and release the primary piston until fluid flows freely from the ports with no evidence of air bubbles.
9. Remove the transparent hoses from the master cylinder reservoir.
10. Install the master cylinder reservoir cap and diaphragm.
11. Remove the fittings with the transparent hoses from the master cylinder ports. Wrap the master cylinder with a clean shop cloth to prevent brake
fluid spills.
12. Remove the master cylinder from the vise.
Master Cylinder Reservoir Filling
Master Cylinder Reservoir Filling
Warning: Refer to Brake Fluid Irritant Warning (See: Service Precautions/Technician Safety Information/Brake Fluid Irritant Warning).
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution (See: Service Precautions/Vehicle Damage Warnings).
1. Visually inspect the brake fluid level through the brake master cylinder reservoir.
2. If the brake fluid level is at or below the half-full point during routine fluid checks, the brake system should be inspected for wear and possible
brake fluid leaks.
3. If the brake fluid level is at or below the half-full point during routine fluid checks, and an inspection of the brake system did not reveal wear or
brake fluid leaks, the brake fluid may be topped-off up to the maximum-fill level.
4. If brake system service was just completed, the brake fluid may be topped-off up to the maximum-fill level.
5. If the brake fluid level is above the half-full point, adding brake fluid is not recommended under normal conditions.
6. If brake fluid is to be added to the master cylinder reservoir, clean the outside of the reservoir on and around the reservoir cap prior to removing
the cap and diaphragm. Use only GM approved brake fluid from a clean, sealed brake fluid container.
