Brake Load Sensing Proportioning Valve Fit For NISSAN NV350 46400-VW000 MB618321 MB618320 OEM: MB618321 MB618320 BU4018 46400-VW000 46400VW000 Function: The function of the valve is to prevent the fluid from flowing back to the master cylinder and maintain a small amount of pressure in the pipeline. This direct-replacement component installs swiftly, no special tools or additional modifications to your vehicle’s braking system are needed., Manufacturer: NADCFN