1973 Mack U Recalls

DEFICIENCIES, IN THE FORM OF FORGING LAPS, CRACKS AND EXCESSIVE DECARBURIZATION DURING HEAT TREATMENT, EXIST IN THE STEERING KNUCKLES. STRESSES IMPOSED WITH INTEGRAL HYDRAULIC POWER STEERING MAY LEAD TO A FAILURE IN THE AREA OF THE STEERING ARM ATTACHING BOSS. THIS TYPE OF FAILURE WOULD CAUSE LOSS OF STEERING CONTROL.

DEALER WILL INSPECT AND, IF NECESSARY, REPLACE THE LEFT STEERING KNUCKLE WITH AN IMPROVED TYPE OF KNUCKLE.

THE FLEX BLADE FANS ON THE INVOLVED VEHICLES MAY DEVELOP CRACKS IN THE LAMINATED STIFFENER AS A RESULT OF FATIGUE DURING OPERATION. IF SUCH A CONDITION EXISTS AND THE CRACKS GO UNDETECTED, CONTINUED OPERATION COULD CAUSE PIECES OF THE STIFFENER TO BREAK OFF.

DEALER WILL REPLACE THE ORIGINAL FAN WITH A STEEL FIXED BLADE FAN, FREE OF CHARGE.

MACK TRUCKS CAMPAIGN NO SC060.TRUCKS MFG'D 1967 THRU JAN.31, 1973.POSSIBILITY THAT THE SUSPENSION TRUNNION BRACKETS MAY DEVELOP CRACKS.IF SUCHCONDITION EXISTS AND CRACKS ARE NOT DETECTED, CONTINUED OPERATION COULDULTIMATELY LEAD TO TRUNNION TUBE SEPARATION FROM THE TRUNNION AND PERMIT AXLEASSEMBLY DISLOCATION.FAILURE…

MACK CAMPAIGN NO SCO#45.EQUIPPED WITH FA535 FRONT AXLE.TRUCKS.POSSIBILITYTHAT THE AXLE BEAM MAY HAVE SURFACE CRACKS ON THE UNDERSIDE BELOW THE SPRINGPADS.SUCH CRACKS COULD OVER A LONG PERIOD OF TIME PROGRESS TO BEAM FAILUREAND LOSS OF VEHICLE CONTROL.(CORRECT BY INSPECTING AND REPLACING WHERENECESSARY).

MACK CAMPAIGN NO 55.MFG'D JAN.1, 1973 THRU AUG.14, 1974.POSSIBILITYTHAT VEHICLES EQUIPPED WITH A TRACTOR PROTECTION VALVE AN INTERFERENCE COULDOCCUR BETWEEN THE STOP LAMP SWITCH AND THE HEAD LAMP SWITCH COULD CREATE ASHORT CIRCUIT THAT WOULD INTERRUPT HEAD LAMP OPERATION.(CORRECT BY INSPECTINGAND PROVIDING ADDITIONAL…