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Automatic Level Control: Description

Pneumatic level control system automatically maintains correct rear trim height of vehicle under varying load conditions. This is done by system automatically regulating air pressure to special shock absorbers. 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. 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 height control valve of not more than 125 psi. Height control valve, linked to rear suspension, admits or exhausts air at 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
G09341395Courtesy of GENERAL MOTORS COMPANY