One problem related to brake fluid leak has been reported for the 2003 Chevrolet Express. The most recently reported issues are listed below.
Driver a noticed lack of pressure in brake pedal. The brake pedal went fully to the floor and resulted in less braking than expected. Driver reduced speed by downshifting to lower gears (automatic transmission) and pulled into first available parking area. By pumping the brakes and pulling into an uphill parking spot, driver achieved enough braking to come to a full stop without using the emergency brake. Inspection showed a nearly full brake reservoir and no leakage from wheel cylinders. Further inspection showed leaking fluid from brake line on left side under the drivers seat and above the vehicle frame. It squirted out from a crack in a brake line when brake pedal was pumped. The vehicle was deemed unsafe to drive. The vehicle was towed for repair.