{"nhtsa_id":612122,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2000-06-06","date":"1999-12-01","document_id":"SF191A","mfr_campaign":null,"replaces":null,"component":"SUSPENSION:REAR:SPRINGS:AIR SUSPENSION SYSTEM","mfr_system":null,"summary":"VEHICLES EQUIPPED WITH WABCO AIR COMPRESSOR MANUFACTURED BETWEEN MARCH 1, 1999 AND JULY 2, 1999 HAVE EXPERIENCE AIR EXHAUSTING TO THE ATMOSPHERE INSTEAD OF GOING INTO THE AIR TANKS WHEN THE RELIEF VALVE OPENS. THE MODIFICATION CONSISTS OF INSTALLING A PRESSURE RELIFE VALVE OF 175 PSI. *TT","document":null,"url":"https://open.wenmarpro.com/bulletins/612122","components":[{"id":"suspension","name":"Suspension","parent":null},{"id":"air-suspension","name":"Air suspension","parent":"suspension"}],"codes":[],"topics":[],"vehicles":[{"make":"FREIGHTLINER","model":"XC","year_from":1999,"year_to":1999,"match":null,"vehicle_ids":[]}],"as_of":"2026-10-19","note":"A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.","attribution":[]}