FAILED TAG AXLE SWING ARMS

What NHTSA is examining

Mci originally filed a defect notification on october 20, 2003, (03v-411) to addresscracks located on the tag axle swing arm at the connection to the pivot spindle tube.four hundred and ninety-three (493) mci g4500 2000-2003 motor coaches were involved.mci?s engineering analysis determined that insufficient weld metal and /or weld penetration on the failed components could result in early stress and fatigue cracks at a weld joining the tag axle to the pivot tube assembly.mci's field repair consisted of inspecting and re-welding the tag axle swing arm.a small percentage were not repairable and required a full replacement of the swing arm. On july 18, 2006, odi was contacted by a fleetalleging that they had three tag axle arms crack and subsequently break in the same area repaired by mci during the safety recall.as a result, odi opened this rq.mci conducted further analysis and determined that some of the previously repaired swing arms, repaired during recall 03v-411 may have been repaired with existing unidentified micro-fractures and/or welds with insufficient penetration.this could lead to further cracking and result in a partial or total separation or the tag arm. As a result of this investigation, mci has announced a new safety recall in which they will replace all the tag arms with a newly designed tag axle swing arm.mci's new recall actionresolves this investigation.therefore, this investigation is closed.odi will continue to monitor the progression of the new recall…

Vehicles under investigation