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Automatic Level Control: Description

This pneumatic level control system automatically maintains correct rear trim height of the vehicle under varying load conditions. This is done by the system automatically regulating air pressure to special type shock absorbers. The system consists of a vacuum operated air compressor (with pressure regulator and integral storage tank), vacuum line to engine, air intake filter and lines, and a height control valve. The compressor is a two-stage type which generates air pressures up to 275 psi in the storage tank. A self-contained regulator valve is preset to maintain pressure to the height control valve of not more than 125 psi. The height control valve, linked to rear suspension, admits or exhausts air to the special shock absorbers as load variances cause a trim deflection of approximately 1/2". A built-in time delay system is incorporated to prevent system operation during normal ride suspension height changes.

Fig 1: Automatic Leveling System
G09347740Courtesy of GENERAL MOTORS COMPANY