MOUNTING OF THE PITMAN ARM MAY LOOSEN AND LEAD TO EXCESSIVE WEAR IN EITHER THE PITMAN ARM SPLINES OR THE STEERING GEAR SHAFT SPLINES, OR BOTH. THIS CONDITION IS DUE TO INCORRECT TIGHTENING OF THE MOUNTING SCREWS DURING ASSEMBLY.
Manufacturer remedy
THE DEALER WILL INSPECT AND PROPERLY TIGHTEN THE PITMAN ARM RETAINING SCREWS.
THE PITMAN ARM RETAINING NUT MAY NOT HAVE BEEN TORQUED TO MANUFACTURER SPECIFICATIONS. THIS COULD RESULT IN INADEQUATE RETENTION OF THE NUT AT THE OUTPUT SHAFT, ALLOWING THE PITMAN ARM TO BECOME LOOSE.
Manufacturer remedy
DEALER WILL INSPECT AND RETORQUE PITMAN ARM, IF NECESSARY, AT NO COST TO OWNER.
IN THE EVENT OF TURBOCHARGER COMPRESSOR WHEEL FAILURE, ONE OR MORE OF THE FOUR CAPSCREWS THAT HOLD THE TURBOCHARGER TOGETHER MAY BE STRUCK BY PARTS OF THE COMPRESSOR WHEEL, RESULTING IN THE CAPSCREWS BEING DAMAGED. IF THESE CAPSCREWS ARE DAMAGED TO THE POINT THAT THEY ALLOW THE COMPRESSOR BACK PLATE TO DISLOCATE FROM THE TURBOCHARGER BEARING HOUSING, ENGINE LUBRICATING OIL MAY BE ALLOWED TO ESCAPE UNDER PRESSURE, CONTACTING THE ENGINE EXHAUST MANIFOLD SECTIONS OR TURBOCHARGER TURBINE HOUSING.
Manufacturer remedy
DEALER WILL INSTALL A SHIELD FOR THE HEADS OF THE FOUR CAPSCREWS, ALONG WITH STRONGER SAE 8 GRADE 8 CAPSCREWS, IF NECESSARY, AT NO COST TO OWNER.
IT HAS BEEN DETERMINED THAT TWO SCREWS THAT ARE PART OF THE BEARING ASSEMBLY LOCATED AT THE CAB DASH SHEET MAY NOT HAVE BEEN TIGHTENED PROPERLY. AS A RESULT, THE UPPER STEERING SHAFT MAY BE FREE TO "FLOAT" THROUGHOUT MUCH OF ITS LENGTH WHICH MAY RESULT IN INADEQUATE ENGAGEMENT IN THE SLIP SPLINES OF THE LOWER STEERING SHAFT. AXLE ARTICULATION COULD RESULT IN DISENGAGEMENT OF THE LOWER STEERING SHAFT SLIP SPLINES.
Manufacturer remedy
DEALER WILL INSTALL A SLEEVE BETWEEN THE DASH SHEET BEARING AND THE UPPER STEERING SHAFT LOWER YOKE TO ASSURE POSITIVE UPPER STEERING SHAFT LOCATION.
Service brakes, air: antilock: interconnecting assembly(wiring)
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
19,370
Reported to NHTSA
1978-10-03
Owners notified
1978-11-07
Defect description
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".
Manufacturer 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.
THE POSSIBILITY EXISTS THAT THE ALUMINUM ENGINE REAR SUPPORT BRACKETS MAY FAIL DUE TO METAL FATIGUE. THIS TYPE OF FAILURE WOULD ALLOW THE ENGINE AND TRANSMISSION ASSEMBLY TO DISLOCATE DOWNWARD. THIS WILL RESULT IN THROTTLE CONTROL LOSS WITH THE ENGINE OPERATING CONTINUOUSLY IN THE MID TO UPPER RANGE OF THE GOVERNED SPEED RANGE.
Manufacturer remedy
DEALER WILL INSPECT AND, IF NECESSARY, REPLACE ALUMINUM SUPPORT BRACKETS WITH BRACKETS MADE FROM DUCTILE IRON FOR INCREASED STRENGTH.
Owner complaints
A complaint is one person's report to a federal agency. It is not a finding.
No complaints recorded for this model year.
Safety recall repairs are provided free of charge by franchised dealers, regardless of vehicle age or mileage. This page displays aggregated data for the model year. To check recall status for a specific vehicle, search its VIN at nhtsa.gov.