Master Cylinder Replacement (JD9, JF3, JF7)

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: View Of Master Cylinder & Components

Courtesy of GENERAL MOTORS CORP.

Callout	Component Name
CAUTION: Refer to Brake Fluid Irritant Caution . NOTE: Refer to Brake Fluid Effects on Paint and Electrical Components Notice . Preliminary Procedures With the engine OFF, apply the brake pedal several times until the brake pedal becomes firm to deplete the vacuum brake booster vacuum reserve. Using a suitable tool, remove the brake fluid from the brake master cylinder reservoir. Discard the brake fluid into an approved container.
1	Master Cylinder Fluid Level Sensor Electrical Connector
2	Brake Pipe Fitting (Qty: 2) NOTE: Refer to Fastener Notice . Procedure Remove any dirt or debris from the brake pipe fitting. Cap the brake pipe fittings to prevent brake fluid loss and contamination. Tighten: 25 N.m (18 lb ft)
3	Brake Master Cylinder Nut (Qty: 2) Tighten: 33 N.m (24 lb ft)
4	Brake Master Cylinder Assembly
5	Brake Master Cylinder to Vacuum Booster Seal Procedure Inspect the brake master cylinder to vacuum booster seal for damage and replace if necessary. Ensure the brake master cylinder to vacuum booster seal is properly seated against the base of the brake master cylinder. Do not place the brake master cylinder to vacuum booster seal in the groove of the master cylinder body. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Manual) or Hydraulic Brake System Bleeding (Pressure) .