westend wrote:
Sounds to me like you have air in the brake lines. Have you ever had the brake system bled?
or
Brake Fluid Contamination
Over time, brake fluid will absorb moisture and this can also cause spongy pedal problems. Water can get into the system through the rubber brake lines. It will lower the boiling point of the fluid so that, under heavy braking, the heat forms bubbles of gas in the fluid itself. This gas is compressible (whereas brake fluid is not); hence the spongy feel in the brakes.
Brake fluid needs to be changed every so often. It was news to me when m mechanic told me but he was right. MAKES A Difference