WHEEL STUD NUT MAINT./SERVICE INFORMATION & TORQUE SPEC.. GMC Truck GMC MD FWD Control Chassis 1987

THE FOLLOWING INFORMATION IS REPRINTED FROM THE MEDIUM DUTY OWNER'S MANUAL, WHICH OUTLINES THE OWNER'S RESONSIBILITIES REGARDING WHEEL FASTENER MAINTENANCE.

WHEN THE VEHICLE, WHEEL OR FASTENERS ARE NEW, THE WHEEL STUD NUTS AND/OR RIM CLAMP NUTS SHOULD BE TIGHTENED WITH A TORQUE WRENCH AT 100, 500, AND 1,000 MILES (160, 800, AND 1,600 KILOMETERS). THIS IS NECESSARY BECAUSE THE CLAMPING SYSTEM USED ON THE WHEELS MUST SEAT BEFORE THE FASTENERS WILL HOLD A UNIFORM CLAMP LOAD AND REMAIN FULLY TIGHTENED.

TIGHTEN WHEEL STUD NUTS AND/OR RIM CLAMP NUTS WITH A TORQUE WRENCH AFTER INSTALLING ANY WHEEL. IN ADDITION, NUT TIGHTNESS ON ALL WHEELS, IN WHICH NEW FASTNERS WERE NOT USED, SHOULD BE SET WITH A TORQUE WRENCH EVERY 1,000 MILES (1,600 KILOMETERS) THEREAFTER.

CAUTION:

IMPROPERLY TIGHTENED WHEEL NUTS COULD EVENTUALLY ALLOW THE WHEEL TO COME OFF WHILE THE VEHICLE IS MOVING, POSSIBLY CAUSING LOSS OF CONTROL, PERSONAL INJURY AND PROPERTY DAMAGE.

FOR PROPER INSTALLATION, SNUG ALL WHEEL NUTS AND THEN TIGHTEN TO THE SPECIFIED TORQUE FOR THE SPECIFIC TYPE OF WHEELS ON THE VEHICLE AS INDICATED IN THE CHART BELOW:

WHEEL NUT TORQUE

NM FT/LBS --- ------- CAST TYPE WHEELS FRONT 271 200 REAR 271 200

BUDD TYPE (DISC) WHEELS (BALL SEAT) FRONT 712 525 DUAL REAR (INNER AND OUTER NUTS) 712 525 * ALUMINUM WHEELS AND/OR HUBS 644 475

CORPORATION TYPE (DISC) WHEELS (FLANGE TYPE NUT) FRONT 475 350 REAR 475 350

(*) LOOSEN OUTER NUTS, TIGHTEN INNER NUTS, THEN TIGHTEN OUTER NUTS.

REFER TO THE APPLICABLE SECTION IN YOUR OWNER'S MANUAL AND/OR SERVICE MANUAL FOR ADDITIONAL WHEEL AND TIRE INFORMATION.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.