The rear exhaust hanger bolt may fall out on some early 1985 Corvettes.
The condition may be caused by loss of clamp load.
1. Add four (4) 8mm (5/16 inch) phosphate coated flat washers between the hanger insulator and bumper extension. The washers are added to prevent the insulator metal sleeve from pulling into the adjusting slot on the bumper extension (see illustration).
2. Replace the four (4) original nuts with four (4) M8-1.25 torque prevailing nuts. Torque nuts to 25 ft. lbs. (34 N.m).
3. If the original bolts are missing, replace with M8 x 1.25 x 45mm flanged hex head bolts.
This change was put into production on 4/2/85 VIN NO.123542
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.