1. Air in the brake lines: When the brake fluid is changed, air can get into the brake lines. This air can compress, causing the brake pedal to feel spongy.
2. Brake fluid leak: If there is a leak in the brake fluid system, air can also get in and cause the brake pedal to feel spongy.
3. Faulty brake master cylinder: If the brake master cylinder is not functioning properly, it can cause the brake pedal to feel spongy.
4. Faulty brake booster: If the brake booster is not functioning properly, it can also cause the brake pedal to feel spongy.
To determine the exact cause of the problem, it is best to take your vehicle to a qualified mechanic for inspection and repair.
