B.E.A. Meeting no. 108: DS hydraulic quality review with Paul Magès (28 January 1959)

In this document

These minutes of B.E.A. meeting no. 108 record a meeting held in Mr. Cadiou's office, in the presence of Messrs. Cadiou, Magès (noted as "Magis"), Louis (noted as "Locin"), Pompon (noted as "Lompon"/"Pampos") and Chalard p. 279. The stated subject is "DS Quality. Hydraulics" p. 279, but the discussion actually extends to numerous mechanical components p. 279-280.

Pump and bearings

The minutes mention a comparison between fluids ("sorb" and "CH12"), endurance defects on seats and liners (particles in the oil), needle wear deemed unconfirmed, and the assembly of the plate bearing: a 5-ball bearing is "launched on 28/1 at SKF" p. 279. It is also noted that no new pump is expected "for several years" p. 279.

Pressure regulator

The current pressure regulator is undergoing laboratory testing, with a question of clearances and oil leaks reported by Mr. Chalard. Mr. Cadiou requests a lead time for 30 steel pressure regulator prototypes; Mr. Magès mentions a series "in 3 years", i.e., "not before January 1960" p. 279. A note is to be drafted by Mr. Magès to look for an alternative metal (steel, AZ5G) p. 279.

Steering, brakes, transmission

The steering shows "less wear" but leaks at the ends; it "can give 50,000 km in Paris, 80,000 km on the road" p. 279-280. Regarding brakes, few warranty returns but external leaks; a distribution spool "to be pushed" is requested by Mr. Louis p. 280.

Suspension, clutch, radiator

Complaints concern "noisy shock absorbers" (Mr. Louis says he owns a car with this defect) and "broken rods" on bad roads p. 280. Regarding the filter, the 5 μ quality "seems sufficient"; a presentation of plans and a car is scheduled for 15/2 with Messrs. Magès and Chalard p. 280. Finally, Mr. Magès must examine the possibility of a steel radiator with a thermostat to limit temperature rise, a source of leaks and corrosion p. 280.

Context

The DS, launched by Citroën in 1955, owes part of its innovative character to the hydropneumatic suspension developed by Paul Magès. This system, entirely new for a mass-produced car, generated teething problems in its first years of production—sealing, part wear, hydraulic pump reliability—typical of a disruptive technology still in industrial shakedown.

The B.E.A. (Automotive Design Office) was, at Citroën, the technical monitoring body where engineers and production managers regularly reviewed these problems, in order to arbitrate between quality requirements and mass production constraints.

Archivist's perspective

This document illustrates, in a very concrete way, the daily development work that followed the launch of the DS: it is less a theoretical reflection on hydropneumatics than an operational follow-up, organ by organ, of the "hot spots" reported in the field and in manufacturing p. 279-280.

It seems that Paul Magès acts as a transversal technical reference—pump, pressure regulator, steering, radiator—tasked with proposing solutions and setting deadlines, which confirms his central role in the industrial monitoring of his invention beyond just the design phase.

This report is part of a set of archives relating to Hydropneumatic suspension plans with differential interaction and automatic leveling, and extends, fifteen years later, the work recorded in the List of problems under study as of 22 February 1944, testifying to the continuity of the work to make the system reliable.