my Volkswagen Golf MK7 (2015-2019) brakes feel soft, what could be wrong?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to prevent electrical issues.

2. Inspect and Replace Brake Fluid

• Remove the master cylinder reservoir cap.
• Check fluid condition; if contaminated or low, replace with OEM brake fluid (DOT 4).
• Tools Required: Brake fluid, funnel, clean rags.
• Safety Warnings: Avoid skin contact with brake fluid as it can damage paint.

3. Inspect Brake Lines and Components

• Visually inspect all brake lines, calipers, and the master cylinder for signs of leaks.
• Tighten any loose connections and replace any damaged lines or components.
• Tools Required: Wrench set, brake line flaring tool (if needed).

4. Bleed the Brake System

• Begin at the furthest wheel from the master cylinder; typically, the passenger rear wheel.
• Use a brake bleeder kit: attach the hose to the bleeder valve and open it.
• Have an assistant pump the brake pedal several times, then hold it down while you close the valve.
• Repeat until no air bubbles are present in the fluid.
• Tools Required: Brake bleeder kit, wrench, container for old fluid.

5. Test Brake Booster

• With the engine running, press the brake pedal several times.
• If the pedal becomes firmer after a few presses, the booster is functioning correctly.
• If it remains soft, the booster may need replacement.
• Tools Required: Vacuum gauge (if testing booster vacuum).