After market anti-theft devices that trap hydraulic pressure in the brake system may cause damage to the anti-lock brake system components. Chevrolet recommends these devices not be used on 1986 vehicles. No information is available regarding compatibility with non-ABS brake systems.
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.