How do you test hydraulic brakes for leaks?

To test hydraulic brakes for leaks, pumping the brake pedal and holding the pressure is an effective method. This technique allows you to determine if there is a loss of pressure within the braking system, which would indicate that there may be a leak. When you pump the brake pedal, you build up hydraulic pressure in the braking system. If the pedal slowly sinks to the floor or feels spongy while maintaining pressure, this is a sign that hydraulic fluid might be escaping due to a leak, either from the brake lines or the brake cylinders.

The other methods listed can provide some useful information but do not specifically test for leaks in the same direct way. Visually inspecting the brake lines may identify issues that are visible, while checking the brake fluid level can show whether there has been a loss of fluid over time. Listening for unusual noises might indicate other problems in the braking system, but it does not effectively test for leakage specifically. Therefore, the process of pumping the pedal and assessing the pressure is central to identifying leaks in hydraulic brake systems.