MACK U 1978: SERVICE BRAKES, AIR:ANTILOCK:INTERCONNECTING ASSEMBLY(WIRING)

General Information

NHTSA Campaign ID Number: 78V210000

Make Model Year
MACK U 1978
Date Owners Notified Date Received by ODI Date Added to Database
1978-11-07 1978-10-03 1979-10-12

Production Dates: 1977-10-01 - 1978-09-01

Manufacturers Involved: Mack Trucks, Inc.

Component: SERVICE BRAKES, AIR:ANTILOCK:INTERCONNECTING ASSEMBLY(WIRING)

Potential Number Of Units Affected: 19370

Report Initiator: MFR MFR Report

Regulation Part Number: 571

Federal Motor Vehicle Safety Standard Number: 121

Summary

DELAYS OF UP TO ABOUT 2 SECONDS MAY EXIST IN THE BRAKE APPLICATION TIMES TO THE BRAKES ON THE BOGIE AXLES IN THE PRESENCE OF CERTAIN TYPES OF WHEEL SPEED SENSOR SIGNAL DISCONTINUITIES OR DISTORTIONS THAT MAY OCCUR AS A RESULT OF SENSOR WIRE FAILURE. THIS CONSTITUTES A NON-COMPLIANCE TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS".

Remedy

DEALER WILL INSTALL NEW WHEEL SPEED SENSORS THAT INCORPORATE IMPROVED WIRING AND THE PRESENT BOGIE ANTI-WHEEL LOCK SYSTEM WILL BE CHANGED TO AN AXLE-TO-AXLE SYSTEM FOR IMPROVED RELIABILITY.

Notes

VEHICLE DESCRIPTION: HEAVY TRUCKS.SYSTEM: SERVICE BRAKES; ELECTRICAL WIRING AND CONNECTORS.CONSEQUENCES OF DEFECT: THIS DELAY IN EFFECTIVE BRAKING ACTION COULD LEAD TO ANACCIDENT UNDER CERTAIN TRAFFIC CONDITIONS.