Citroën Laboratory report on shock absorber and reservoir (14 March 1952)

In this document

This sheet is a report from the André Citroën Laboratory (53, rue Balard, Paris), dated 14 March 1952, referenced "Test no. 220.675" p. 94. It follows the examination of drawings transmitted by the Design Office via "STUDIES Note no. 42.401 T of 10-3-52" p. 94, and concerns three points of the hydraulic suspension: the shock absorber, the accumulator support and the reservoir.

Shock absorber

The laboratory requests the removal of a shim (referenced E.401.396.c), to be replaced by a shoulder on the seat or on the valve. It also requests the replacement of the valve E.401.397.c with a rigid valve "at least 2 mm thick", or failing that, a quick test of this solution. The laboratory gives its approval to screw and then crimp the shock absorber onto the sphere p. 94.

Accumulator support

On this point, the note is laconic: "Nothing to say." p. 94.

Reservoir

The laboratory wishes for the reservoir sieve to be easily visible, in order to distinguish clogging from a puncture. It also requests that the lower attachment lugs of the reservoir support straps have a rounded edge, to prevent the straps from bending at a right angle — in explicit reference to the "petrol tank" p. 94.

The document bears a handwritten note "M. Magès" in the margin, as well as a partially legible signature "A. [uncertain]" p. 94.

Context

The André Citroën Laboratory played, in the industrial organisation of the brand, the role of technical evaluator of the solutions proposed by the Design Office — here directed, for the suspension, by Paul Magès, who joined Citroën in 1925 and was then deputy head of Super-Control after his time at the design office (autobiographical notes). In 1952, work on the hydropneumatic suspension — whose first drawings date from 17 February 1944 (hydropneumatic suspension drawings) and whose first tests on 2 CV took place in 1946 (notebook of first tests) — was progressing towards what would become the system equipping the future DS, presented on 6 October 1955. The elements mentioned — shock absorber, accumulator (sphere), reservoir — are central components of this hydraulic system, whose oil provides both suspension, braking and power steering.

Archivist's perspective

This report illustrates the routine technical dialogue between the test laboratory and the Design Office during the development phase of the hydropneumatic suspension. The handwritten note "M. Magès" suggests that this document was directly intended for him or transmitted for information p. 94.

The remarks, very concrete — thickness of a valve, shape of a strap lug edge —, show the degree of industrial detail necessary before manufacturing. It is a milestone among the long chain of tests that will lead, two years later, to the 15-Six H test then to the presentation of the DS, in continuity with the hydropneumatic suspension drawings drawn up a few years earlier, and to be compared with the general context of the file described in the summary of folder 41-59.