Investigations
AIR COMPRESSOR DISCHARGE LINE
NHTSA Preliminary Evaluation PE08069 — closed, opened 2008-12-09 and involving the MACK MACK.
NHTSA investigation PE08069 is a Preliminary Evaluation opened on 2008-12-09 and currently closed. The subject of record is MACK MACK, which places this file inside the Office of Defects Investigation queue for MACK. Latest activity on this investigation was logged on 2009-07-01 — NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
A Preliminary Evaluation like PE08069 is the entry point of the federal defect-investigation process. NHTSA engineers scan complaint databases, field reports, and manufacturer data to decide whether an Engineering Analysis is warranted, whether a voluntary recall is already sufficient, or whether the pattern does not rise to a defect finding.
Investigators summarized the matter as follows: "ODI opened this investigation based on a review of Early Warning Field reports which indicated instances of the air compressor discharge line coming loose or separating on certain model year 2008 Mack Trucks. Further rev..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time. Related MACK files, listed below, give context on whether this is an isolated concern or part of a broader pattern across the brand.
Investigation Summary
ODI opened this investigation based on a review of Early Warning Field reports which indicated instances of the air compressor discharge line coming loose or separating on certain model year 2008 Mack Trucks. Further review indicated that Mack had issued a Service bulletin (#SB 531014) in May 2008. A revised air line was incorporated into production in May 2008 and the ferrule type fitting was changed to a 37 degree flare compression type fitting. The failure resulted in a diminished air supply to the truck's braking system. During the investigation, ODI collected information from Mack, examined warranty claims, discussed the problem with fleet managers and confirmed that the subject vehicles meet the requirements of FMVSS 121, (Air Brake Systems). This standard includes a requirement for an air pressure gauge, and an audible and visual warning signal. The air system normally operates at 100 -120 psi. If the air discharge line becomes loose, the system will continue to hold air but replenishment may be diminished depending on the degree of leakage. If the air line separates, air system replenishment will cease and air pressure will drop as system air is used during brake applications. As the air pressure drops, the dashboard mounted gauge provides a continuous pressure status. Drivers are required to have a CDL (commercial drivers' license) with air brake endorsement and part of the training to obtain such a license includes learning how to monitor and respond to the air pressure system gauges. As the pressure drops below 60 psi, the audible/ visual warning device activates alerting the driver to take appropriate action to stop the truck in a safe location. If the air pressure is allowed to drop below 45 psi, the parking brakes will began to apply. ODI confirmed that approximately 94% percent of the trucks have "engine brakes" that provide supplemental braking and allow a driver with a leaking discharge line to use the compression of his engine to slow the truck, th
About This Investigation Type
A Preliminary Evaluation (PE) is the first phase of NHTSA's investigation process. It is opened when the agency identifies a potential safety defect pattern, usually triggered by consumer complaints, manufacturer reports, or field monitoring. During a PE, NHTSA gathers information to determine whether a formal engineering analysis is warranted.
Other MACK Investigations
mDrive Transmission Failure to Disengage
Vehicle Roll Away
Failing 5th wheel attachment bolts
INTEGRAL HUB AND BEARING ASSEMBLY
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. Learn more.
Read our methodology — how this data is sourced, computed, and verified.