Bench Bleeding - Chevrolet Trailblazer Service Manual

Bench Bleeding

CAUTION
All new master cylinders should be bench bled prior to installation. It is very difficult to
remove the air trapped in the master cylinder once it is installed on the vehicle. You will
also introduce air into the vehicle's hydraulic brake system.
1. Secure the master cylinder in a bench vise using soft jaws.
2. Remove the master cylinder reservoir cap.
3. Manufacture or purchase bleeding tubes and install them on the master cylinder.
4. Fill the master cylinder reservoir with clean, fresh brake fluid until the level is within
0.25 in. of the reservoir top.
NOTE: Ensure the bleeding tubes are below the level of the brake fluid, otherwise
air may get into the system making your bleeding efforts ineffective.
5. Use a blunt tipped rod to slowly depress the master cylinder piston. Make sure the
piston travels its full stroke.
6. As the piston is depressed, bubbles will come out of the bleeding tubes. Continue
depressing and releasing the piston until all bubbles cease.
7. Refill the master cylinder with fluid.
8. Remove the bleeding tubes.
9. Install the master cylinder reservoir cap.
10. Install the master cylinder on the vehicle.