Paul Magès' internal memo regarding defective balls in DS HP pumps (2 December 1957)

In this document

This internal memo, signed by Paul Magès and dated 2 December 1957, is addressed to Messrs. Inguenean and Hartman, with a copy to Mr. Sabazot and for information to Messrs. Delerive, Louis and Ponyon p. 11.

The reported problem

Magès recalls a telephone communication from 15 November by which he had already alerted his recipients about "the first 8 pumps returned by customers with defective 4111.S balls" p. 11. Since then, he indicates having received "another 7 pumps showing this same defect", as well as an additional pump whose 4102.S counter-thrust balls are "damaged in the same way" p. 11.

The suspected origin

Magès specifies that "it seems established that the incriminated 4111.S balls are not of SKF origin", while noting that it remains to be verified if this is also the case for the 4102.S balls p. 11.

The instruction given

The memo concludes with a firm instruction: "it is necessary to exclude, for the DS pump, all balls from sources other than SKF" p. 11. The document bears an entry stamp dated "2 DEC. 1957", a red checkmark above the title, as well as an illegible handwritten signature at the bottom of the page.

Context

This note is part of the context of the DS 19, launched by Citroën in 1955, whose hydropneumatic suspension system — a major invention by Paul Magès — relied on high-pressure pumps essential to the proper functioning of the vehicle.

SKF, a world-renowned Swedish manufacturer of ball bearings, was a benchmark supplier for the automotive industry at that time. The use of balls of non-approved origin, causing customer returns, illustrates the classic tensions between the quality of subcontracted components and the reliability of an innovative technical system, still young in its mass production phase.

Archivist's perspective

This document testifies to Magès' constant concern for the industrial reliability of his invention: beyond the design, he personally follows the field incidents reported by customers, proof of direct involvement in the quality monitoring of HP pumps.

The coincidence of the date with the SKF letter of 2 December 1957 regarding defective balls for the DS 19 HP pump strongly suggests that this internal memo responds to or echoes a concomitant exchange with the SKF supplier itself — probably to formalize internally the corrective measures decided following this contact.

It seems that this incident had concrete consequences: the flow tests of the DS HP pump conducted at the Hydraulic Laboratory in November 1958 and the request for a pre-series of 100 pumps testify, the following year, to an increased effort in quality control on this sensitive component.