Brake pedal soft A6 C7

Tools Required

• OBD-II Scanner
• Brake Bleeder Kit
• Wrench set (including flare nut wrenches)
• Brake Fluid (DOT 4)
• Vacuum pump
• Jack and jack stands or a hydraulic lift
• Torque wrench
• Inspection mirror
• Flashlight

Step 1: Visual Inspection

1. Check Brake Fluid Level:

   • Open the hood and locate the brake fluid reservoir.
   • Ensure the fluid level is between the "MIN" and "MAX" lines. Low fluid might suggest a leak.

2. Inspect for Leaks:

   • Inspect the brake lines, calipers, and master cylinder for any visible signs of fluid leakage.
   • Use an inspection mirror and flashlight to check hard-to-see areas.

3. Check Brake Pads and Rotors:

   • Inspect the brake pads for wear. Thin pads can cause a spongy pedal.
   • Check rotors for warping or damage.

Step 2: Functional Tests

1. Brake Booster Test:

   • With the engine off, pump the brake pedal several times until it becomes firm.
   • Hold the pedal down and start the engine. The pedal should move slightly downward if the booster is functioning properly.

2. ABS and Brake System Codes:

   • Connect an OBD-II scanner.
   • Check for any stored codes related to the ABS or brake system.

Step 3: Air in Brake Lines

1. Bleed the Brakes:
   • If air is suspected in the brake lines, bleeding the system is necessary. Follow the vehicle-specific procedure for bleeding brakes, starting from the wheel farthest from the master cylinder.

Repair Instructions

Step 1: Bleeding the Brake System

1. Preparation:

   • Ensure the car is on a level surface.
   • Use a jack to lift the car and secure it on jack stands.

2. Bleeding Process:

   • Begin with the rear passenger side wheel.
   • Remove the wheel and locate the bleeder valve on the brake caliper.
   • Attach the brake bleeder kit to the valve.
   • Open the bleeder valve and have an assistant press the brake pedal slowly.
   • Close the valve before the assistant releases the pedal.
   • Repeat until no air bubbles are visible in the fluid.
   • Repeat this process on the other wheels in the following order: rear driver side, front passenger side, front driver side.

3. Top Off Brake Fluid:

   • After bleeding, ensure the brake fluid level is at "MAX" in the reservoir.
   • Use only DOT 4 brake fluid.

Step 2: Check for Master Cylinder Faults

1. Test Master Cylinder:

   • If bleeding the brakes doesn't resolve the issue, suspect a faulty master cylinder.
   • With the engine off, press the brake pedal and hold it. If it sinks slowly, the master cylinder might be leaking internally.

2. Replace Master Cylinder:

   • Drain the brake fluid.
   • Disconnect the brake lines from the master cylinder using flare nut wrenches.
   • Unbolt and remove the master cylinder from the brake booster.
   • Install the new master cylinder and reconnect the brake lines.
   • Refill and bleed the brake system again following the earlier steps.

Final Check

1. Test Drive:

   • Carefully test drive the vehicle to ensure the brake pedal feels firm and responsive.
   • Check for any warning lights on the dashboard.

2. Re-inspect Fluid Levels:

   • After the test drive, recheck the brake fluid level and inspect for any leaks.

By following these steps, the soft brake pedal issue should be resolved, ensuring safe and effective braking performance. If problems persist, consider consulting with a professional technician or Audi dealership.