1953 - 1968 Corvette: Chevrolet Engineering Service Letter: Corvette Auto Jack Low-Height Restriction
Source: Chevrolet Engineering Service Letter:
Section: 68-8, Page 29, #925
Subject: UPC X - Wheels and Tires - Corvette Auto jack "Low-Height Restriction" - Corvettes-All Years (1953 - 1968)
Reports have been received of the Corvette Jack #3825993 failing to raise the vehicle with the jack at its extreme "low-height" position and the vehicle at full load.
Under the above conditions, the jack has insufficient mechanical advantage to overcome the vehicle weight resulting in excessive force on the jack operating mechanism.
Production has deviated from the original Jack design by adding a shim to the upper Jack brace which will limit the "low-height" to apprxoimately four inches and provide the necessary mechanical advantage.