2017 Mci D4505

During the review of Motor Coach Industries (MCI) Early Warning Reporting (EWR) 2016 Q4 data, field reports were identified that described fires on 2 buses from different regions of the country.These fires were alleged to have occurred as a result of a loose clamp allowing the tailpipe to separate from the exhaust after treatment assembly.During exhaust after treatment regeneration high temperature gases were directed at the plastic rear bumper.Prior to the fires, there were no indications (such as soot trails) that the clamps were loose.When contacted, the fleet maintenance manager stated all maintenance schedules and DOT inspections had been performed without a failure citation of the exhaust systems. MCI addressed the issue by installing additional brackets to the pipe on all the other buses in the fleet ensuring the tailpipe stayed intact should the clamp lose torque.In correspondence with another fleet using the same style bus, the fleet safety manager described having loose clamps resulting in fires.The MCI fix for the second fleet was to install a shield at the rear bumper to deflect the high temperature exhaust gases in the event of the tailpipe separated from the exhaust after treatment system.This fix was different from the first fleet.During review of communications submitted in March 2017, the Office of Defects Investigation (ODI) identified MCI Service Bulletin No. 309 regarding a maintenance procedure of the exhaust system Torca Accuseal clamp.This bulletin instructed that a new clamp must be utilized after any service or maintenance is performed in which the existing clamp was loosened or removed.ODI requested further information on this bulletin and received warranty claims showing loose tailpipes.MCI has taken the position that fires at the clamp location were due to improper maintenance by the fleets.After analysis of data, provided by MCI to ODI in response to an information request letter, ODI found there was not an increasing number (claim rate of 1.1%) of failures and fires even with portions of the fleet having over seven years in service.The 4 fires identified were from 2 fleets.ODI contacted the fleets with fire incidents and was informed that one of the two buses involved in the fire incidents was sold in 2016 and other fleet does not have maintenance records since they only keep records for one year.ODI is closing the investigation as no actionable trend has been identified.This investigation is closed. Further use of agency resources does not appear to be warranted. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist. The agency reserves the right to take further action if warranted by the circumstances.

WHILE CHANGING LANES AT FREEWAY SPEED TO GO AROUND A SLOW MOVING VEHICLE, THE "COLLISION AVOIDANCE SYSTEM" SLAMMED ON THE BRAKES. I WAS LUCKY TO NOT LOSE CONTROL OF THE BUS! THESE SYSTEMS THAT SENSE SUPPOSED DANGER AND TRY TO DO THE DRIVING FOR YOU ARE EXTREMELY HAZARDOUS AND NEED TO BE BANNED!

NHTSA ID

10991515

Incident

May 3, 2017

Mileage

34,000 mi

This TSIB is to inform customers the recommended steering axle cleaning/greasing instructions to prevent damage on axle components due to displacement of grease from the bearings, lubrication reduction and accelerate wear for coaches with independent front suspension.

Information to owners showing the proper procedure for checking the oil level in a BITZER HVAC compressor.

Technical Service Information Bulletin describing the replacement of seating backrest attachment hardware with the addition of a mechanical lock nut on specifically equipped buses manufactured prior to model year 2020.

This Technical Instruction is a description of the inspections and cleaning procedures being recommended by MCI due to the parts shortages which are impacting the repair inspections associated with NHTSA Recall 21V-748. These are the same instructions as outlined in the previously submitted Technical Services Information Bulletin TSIB 22-01 and Technical Instruction ITS60421, except they are specific to those customers operating in extremely corrosive environments.

This Instruction to Service (ITS) is a description of the inspections being recommedned by MCI due to the parts shortages which are impacting the repair instructions associated with NHTSA Recall 21V-748. These are the same instructions as outlined in the previously submitted Technical Service Information Bulletin TSIB 22-01.

This is an upgrade to Technical Service Information Bulletin TSIB 21-10 issued in January of 2022 which is specific to buses operating in severe duty and or corrosive environments. These bulletins have been issued to recommend interim inspection procedures required every 6000 miles on specifically equipped motor coaches due to global parts shortages and the subsequent delay in available parts to conduct the corrective actions associated with NHTSA Recall 21V-748.