One problem related to brake master cylinder has been reported for the 2000 Volvo V40. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2000 Volvo V40 based on all problems reported for the 2000 V40.
Brake system in car works poorly when car is cold or left for a few hours. Significantly more brake pressure is required to stop the car when car is cold. Problem has been "fixed" three times but has returned again. Evidently this is related to failure of a vacuum pump used to provide additional brake vacuum for the master cylinder when the engine is cold.