GM 19432946
Master Cylinder

You need to wait with the ignition off and ensure no brake pedal application for 1 to 3 minutes to drain pressures from the brake modulator and hpa before replacing the master cylinder on jd9, jf3, jf7 two-mode hybrid models. Once you have waited pressurize the system take the brake fluid out of the reservoir and put it in a permitted storage tank. Untwist the Brake Fluid Level Sensor wiring connection then disconnect the Brake Master Cylinder reservoir return hose and supply hose using quick connects and place them off to the side. Separate and seal the primary brake tube connection and also seal the left right and front brake line fittings. Detach the Brake Master Cylinder nuts from the system and replace them, then remove the Brake Master Cylinder including the master cylinder seal. Before mounting insert the Brake Master Cylinder seal deeply into position before you put in the master cylinder to the adaptor. Put on 2 new Brake Master Cylinder nuts and apply torque to 33 nm (24 lb ft). You should join all brake fittings from left front, right front, right supply, left supply, and primary brake systems. Tighten the connections to 30 nm (22 lb ft). Rejoin the Brake Master Cylinder reservoir return hose quick connector and supply hose quick connector. Also add the Brake Fluid Level Sensor electrical connection. Put fluid in the master brake cylinder reservoir and take fluid out of the hydraulic brake system for testing.