Chrysler’s 1959 “Air‑Sweep” / Constant‑Level (air‑assisted) rear suspension — how it works
Summary
· Chrysler kept conventional leaf springs at the rear and added an air‑assist/leveling system that supported the rear under load and restored normal ride height automatically. Key components: engine‑driven compressor, high‑pressure storage tank (front frame), low‑pressure reservoir on the rear axle, airbags at the rear, and a leveling valve that controlled air to the bags. forwardlook.net
How it functions (step‑by‑step)
1. Compressor and tanks: An engine‑driven air compressor pressurizes a high‑pressure storage tank located near the front of the frame. Air is supplied to the rear via plumbing; a low‑pressure reservoir is mounted near the rear axle. forwardlook.net
2. Airbags added to the rear: Rubber air springs (bags) are fitted at the rear in parallel with the existing leaf‑spring/axle assembly. The leaf springs remain so the car is still drivable if the air system fails. forwardlook.net1
3. Leveling valve senses ride height: A mechanical leveling/height valve monitors rear ride height (or relative axle position). When extra load compresses the rear and the ride height drops, the valve opens to admit air to the rear bags. forwardlook.net
4. Bags support load: The bags inflate, taking some of the load and raising the rear back to its designed level; this preserves headlamp aim and handling. When load is removed, the valve bleeds air and the bags deflate to normal. forwardlook.net
5. System design choice: Chrysler left leaf springs in place as a fail‑safe and used air only as a helper/leveling aid rather than full pneumatic suspension. The system was marketed as Constant Level (Torsion‑Aire + air assist on some models). forwardlook.net1
Practical notes
· Purpose: automatic rear leveling under heavy load, improved control and headlamp aim. forwardlook.net
· Failure behavior: because leaf springs remained, loss of air leaves a drivable (but lower) rear—unlike full air‑suspension designs
From: 'Keith Langendorfer' via Chrysler 300 Club International <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Sent: Friday, May 15, 2026 5:27 PM
To: John R. Cote <cotejohnr@xxxxxxx>; Club Chrysler <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Subject: Re: {Chrysler 300} 300E Vert at B, J , Columbus in June
Beautiful example and I had no knowledge of that rare rear suspension option.
Was this car at our meet in Pasadena in 2022?
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