1. Low Brake Fluid Level:
- Check the brake fluid level in the reservoir. If it's low, top it up with the recommended brake fluid specified for your Peugeot 106.
- If the brake fluid level drops rapidly again after topping up, it suggests an active leak.
2. Damaged Brake Line or Hose:
- Inspect the brake lines and hoses for any visible signs of damage, cracks, or leaks, particularly around the rear disk area.
- Replace any damaged brake lines or hoses.
3. Worn Brake Pads:
- Check the thickness of the rear brake pads. If they are excessively worn, they may not be applying sufficient pressure to the rotors, causing a light brake pedal feel.
- Replace worn brake pads with new ones.
4. Faulty Brake Master Cylinder:
- A faulty brake master cylinder can cause a light brake pedal and fluid leaks.
- If the brake master cylinder is defective, it needs to be replaced.
5. Air in the Brake Lines:
- Air trapped in the brake lines can cause a spongy or light brake pedal.
- Perform a brake fluid flush to remove any trapped air from the system.
If you're not comfortable inspecting or repairing brake components yourself, it's recommended to have a professional mechanic diagnose and fix the issue to ensure safe braking performance.