Photographs of worn suspension parts — shots no. 39636 to 39640

In this document

Plate 1 (p. 111-112)

The first plate presents four photographs arranged in a grid, each showing an O-ring or a sealing ring of oval shape, made of grey-black elastomer material, photographed against a white background p. 111. The four rings show signs of wear: whitish or eroded marks on the inner edge for the two top photos, frayed or jagged areas for the two bottom photos p. 111. A number "1" in red ink, underlined, appears at the bottom of the page p. 111.

The reverse bears the handwritten annotation "39636.35.36.37", likely corresponding to the shot numbers of the four photographs p. 112.

Plate 2 (p. 113-114)

The second plate contains three photographs of annular rubber parts, with a ribbed section suggesting O-rings or sealing rings p. 113. The part at the bottom left shows a mark or crack visible on its inner surface p. 113. A number "2" in red pencil appears at the bottom of the page p. 113.

The reverse bears the reference "39638-39-40", as well as a vertical handwritten inscription in blue pen whose content is not transcribed p. 114.

No date, name, or explicit caption appears in the provided transcriptions: the 1952 dating is not confirmed by the text of the document itself.

Context

These shots document, in all appearance, aging or wear tests of sealing parts — rubber seals or rings — probably intended for the hydropneumatic suspension developed by Paul Magès for Citroën. This suspension, whose first plans date from 17 February 1944 (Hydropneumatic suspension plans with differential interaction (17 February 1944)) and whose first tests on 2 CV took place in May-July 1946 (Notebook of the first 2 CV hydropneumatic suspension tests (May-July 1946)), was then tested on the 15-Six H in April 1954 (Road test of the 15 Six H (ELV 412) by Paul Magès, 3-5 April 1954) before equipping the DS presented on 6 October 1955. This system relied on hydraulic cylinders whose sealing constituted a major technical challenge; a check dated 1952 would thus fit into the development phase prior to the presentation of the DS.

The photographic control of worn parts, numbered and archived, is part of the common practices of post-war automotive design offices to qualify the durability of components before industrialisation. Nothing in the document, however, allows these parts to be attributed to a specific model or programme.

Archivist's perspective

These two plates likely come from a test report or a quality control file related to Paul Magès' work on the sealing components of the hydropneumatic suspension. The continuous numbering of the shots (39636 to 39640) suggests a systematic photographic series, undoubtedly carried out by the technical department to document cases of wear identified during tests (p. 111, p. 113).

The annotations "1" and "2" in red ink indicate a classification or numbering of plates within a larger set, currently incomplete in the transcribed pages.

This document likely finds its place in the more general file of the Folder "Theoretical study – hydropneumatic suspension 1943/44", devoted to the technical developments of this system, even if the direct link between the two items remains to be established for lack of explicit mention in the transcriptions.