C 2500 Truck 2WD V8-5.7L VIN R (1997)
Brake Master Cylinder: Service and Repair
Master Cylinder Bench Bleeding
The purpose of bench bleeding the master cylinder is to remove the air from it prior to installation. This reduces the amount of bleeding needed after it is
installed on the vehicle.
1. Plug the outlet ports and mount the master cylinder a vise with the front end tilted slightly down.
2. Fill the reservoir with clean brake fluid.
3. Using a tool with a smooth, rounded end, stroke the primary piston about 25 mm (1 inch) several times.
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As air is bled from the master cylinder, the primary piston will not travel the full 25 mm (1 inch) stroke.
4. Reposition the master cylinder in the vise with the front end tilted slightly up.
5. Again stroke the primary piston about 25 mm (1 inch) several times.
6. Reposition the master cylinder in the vise to the level position.
7. Loosen the plugs one at a time and push the piston into the bore to force the air from the cylinder.
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To prevent air from being sucked back into the cylinder, tighten the plug(s) before allowing the piston to return to its original position.
8. Fill the reservoir.
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Perform normal bleeding procedures after the master cylinder is installed. Refer to Hydraulic System Service and Repair. See: Service and
Repair
