One problem related to brake fluid leak has been reported for the 2001 Volvo S40. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Volvo S40 based on all problems reported for the 2001 S40.
While driving brake warning light went on. Brake pedal got soft & slowly went to floor. When vehicle was checked it was discovered that the brake lines to rear brakes had rusted through and were leaking fluid. Master cylinder was almost empty. The brake lines on this car are supposed to be made of a rust resistant nickel/copper material but they rusted through.