1978 Mack Rws recalls

A SHORT CIRCUIT COULD OCCUR DUE TO CHAFING OR WIRE DISCONNECTION IN THE BOX.

THE WIRING IN THE SLEEPER BOX WILL BE CORRECTED, FREE OF CHARGE.

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".

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.

DEALER WILL INSPECT AND, IF NECESSARY, REPLACE ALUMINUM SUPPORT BRACKETS WITH BRACKETS MADE FROM DUCTILE IRON FOR INCREASED STRENGTH.

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.

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.

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.

DEALER WILL INSPECT AND RETORQUE PITMAN ARM, 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.

DEALER WILL INSTALL A SLEEVE BETWEEN THE DASH SHEET BEARING AND THE UPPER STEERING SHAFT LOWER YOKE TO ASSURE POSITIVE UPPER STEERING SHAFT LOCATION.