Checking for external brake fluid leaks (Opel Insignia A)

1. Check the brake fluid level in the master cylinder reservoir. While a slight decrease in brake fluid due to wear of the brake pads is normal, a significant drop in the brake fluid level in the reservoir indicates leaks in the hydraulic brake system.

2. If the brake fluid level in the reservoir is too low, add fluid to the required level.

3. Start the engine and let it idle.

4. Apply constant, moderate pressure to the brake pedal. If the pedal gradually moves downwards under foot pressure, there may be a leak in the system.

5. Turn off the ignition.

6. Visually inspect the following brake system components for leaks, excessive corrosion and damage, paying particular attention to all brake line and hose connections to ensure there are no loose fittings:

• Master cylinder connections.
• All brake pipe connections.
• Brake lines.
• Brake hoses and connections.
• Brake calipers and/or wheel cylinders.

7. Although a little moisture around the master cylinder reservoir is acceptable, leaking brake fluid from any brake system component is a major sign of a leak. If any brake system component shows signs of leakage, it should be repaired or replaced. After repair or replacement, make sure the brakes are functioning properly.