C 2500 Truck 2WD V8-6.5L DSL Turbo VIN S (1997)
Brake Master Cylinder: Testing and Inspection
Low Pressure Check
This procedure checks for internal seal damage, porosity and component bore integrity by the following procedure:
1. With the ignition switch in the "OFF" position, pump the brake pedal until all brake booster assist has been depleted (5 times for vacuum assisted
brakes and 25 times for hydraulic assisted brakes).
2. Apply the brake pedal at a slow rate (approximately 1/8 inch per second) to generate pressure in the master cylinder and gradually increase pedal
force, and observe for gradually increasing brake pedal travel or the "falling away" feel.
3. If the brake pedal tends to fall away, refer to High Pressure Check. See: High Pressure Check If the high pressure check is good, the master
cylinder has an internal leak.
