15774.004 FOOT VALVE FOOTVALVE NISSAN UD CWA CWA45 CWA46 NISSAN UDFOOT VALVE FOOTVALVE CWA45 CWA46 NISSAN UD EVEN WHEN YOU FIT A BRAND NEW VALVE , THERE IS ALWAYS THE CHANCE THAT IT LEAK WITHIN A WEEK , A MONTH OR A YEAR , AS TRUCKS AIR LINES GET OLDER THE CHANCE OF SCALE AND RUBBISH IN THE BRAKE PIPES INCREASES AND INCREASES A LOT WHEN THERE IS MOISTURE IN THE SYSTEM, SO, OTHER THAN REPLACEING "ALL" THE BRAKE PIPES THERE IS NOT A LOT YOU CAN DO. HOWEVER , THERE ARE IN LINE FILTERS THAT DO STOP SCALE AND OTHER