I have a Honda civic prosmectic exi 2006. When I purchased it as used car in 2013 I found its brake oil quite dark in color. So I replaced it with fresh brake oil and bleed air from all four tires thoroughly. During replacing new brake oil I took special care not to let the brake fluid reservoir bottle empty so that it may not damage the master cylinder. Now since that day I feel the brake pedal is soft and brakes start to come in action when brake pedal travels about 2 to 2.5 inches downwards. Later, I twice again bleed the brake system in order to remove any left over air in the braking system but no improvement has been noticed. Do you think I need to change the master cylinder washers which might have worn out due to aging factor or there is something else wrong with it. Kindly suggest me an appropriate solution.