For 1990-2009 cars

# 'TC' STEEL WHEEL BALANCE INFORMATION

#### MODELS AFFECTED: 1983 Riviera

In May, 1983, a new steel wheel, code "TC", Part No. 9590967 (Figure 1), went into production on 1983 Rivieras. The new wheel may be used as a service replacement for existing steel wheels back to 1979 Rivieras. This wheel incorporates a new manufacturing process in which the five (5) bolt holes and the pilot hole are machined at the same. Use of this process is to minimize radial wheel runout.

Some difficulty may be encountered when attempting to balance the first group of the new production steel wheels. These wheels, carrying a disc code "C" (March) stamped near the bolt circle, have a pilot hole design which interferes with the service balancer wheel mounting cones when the wheel is mounted from the back side. Accordingly, all wheels date stamped "C" should be mounted to a wheel balance machine with the wheel front side to the mounting cone. If mounted from the back side, the "C" stamped wheels may be off by about one ounce of static balance.

Wheels with a date stamp "E" (May) and later, may be balanced in a conventional manner. No wheels date stamped "D" (April) were built.

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.