GM 20812023
Master Cylinder

You must press and release the brake pedal several times before starting the Brake Master Cylinder replacement. Disconnect the battery negative cable. You need to move the electrical center and powertrain control modules aside from the underhood electrical center bracket before you can take out the bracket. Remove the connection between the brake fluid level indicator switch and its electrical system. Separate the master cylinder secondary brake pipe fitting and install the cap while plugging the master cylinder outlet to protect brake fluid from loss and contamination. Afterward remove the master cylinder primary brake pipe fitting and seal the opening with proper caps. Pull off the Brake Master Cylinder nuts and detach the Clutch Hose from the clutch unit when equipped. Secure the joints after sealing the master cylinder clutch port. Separate both the master cylinder assembly and the part that joins with the Brake Booster vacuum. Place the master cylinder on the Brake Booster vacuum seal after you bleed it on a bench press until the seal fits in its designated groove. Attach the master cylinder Clutch Hose quick connect fitting to the vacuum Brake Booster while placing the master cylinder in its correct position. Thread and fasten the Brake Master Cylinder nuts at a torque of 22 nm (16 lb ft). Attach the master cylinder primary pipe connection and tighten it to 21 nm (15 lb ft). Then you need to join the master cylinder secondary brake pipe and adjust its bolt to 21 nm (15 lb ft). Secure the underhood electrical center bracket and place the electrical center and powertrain control modules right against it. Reconnect the battery negative cable. Completing the hydraulic brake system flow process concludes the maintenance procedure.

Disconnect the battery negative cable.

Disconnect the master cylinder primary brake pipe fitting, capping the fitting and plugging the outlet port.