DS/ID hydraulic defect reports and 100,000 km quality schedules (1957)

In this document

This file brings together the quality monitoring documents established by Paul Magès and his Manufacturing Methods team in the autumn of 1957, concerning the 'DS-ID. 100,000 km Quality' project.

Manufacturing schedules

Three schedule sheets ('Sheet No. 1, 2, 3') dated 1957 list, item by item, the defects under study on hydraulic and mechanical components: brake pedal assembly, HP pump rotary seal, pump noise, leaks on cut-out valve, height corrector, suspension cylinders, shock absorbers that lock up, Rilsan rotary seal, clutch and gear control cylinders p. 187-188, 191. Internal notes are cited: Note No. 3, No. 4, No. 5, No. 7, No. 8, No. 9, No. 10 to Messrs. Cadiou and Colombot p. 187-188, 191, as well as a mention 'Seen by Mr. Igueneau on 24.10.57' p. 191.

Measurement and defect reports

A table of pressure measurements on the hydraulic block (137 lines divided into three blocks) records for each part the cut-out pressure, cut-in pressure, stabilisation pressure and the ΔP deviation, with numerous red mentions 'Leaks until cut-in' or 'irregular' p. 186.

Field defect counts appear several times: on the cut-out valves, '118 cut-out valves were examined', of which 13 had an internal leak bringing the pressure back to the cut-in level and 4 with slightly higher stabilisation p. 204. On the clutch re-engagement correctors, 300 units examined: 169 without leaks, 131 with leaks p. 204, and a precise follow-up of two returned correctors (chassis 24672 and 24903, with a seal found cut) is dated 21.10.57 p. 205.

A report on the HP pump (shaft output sealing ring) dated 13/10/57 compares the old ring (Ø19) and the new ring (Ø18): 54% of 'scuffed or scratched' rings for the old one against 43% for the new one p. 202. A summary table of 'Hydraulic components returned by customers examined at Asnières' (notes No. 24 to No. 40, September-November 1957) details HP pumps, steering and cut-out valves with chassis number, mileage and observation (untreated needles, twisted seals, un-locked nuts) p. 207. A second report dated 15/11/57 concerns 628 HP pumps examined, including 28 broken stop fingers, with a chassis table and a sketch showing the rupture zone 'at approximately 40 mm' p. 208.

Two 'Clutch release cylinder seal test' forms (E 806-2286) appear blank, with no data filled in p. 195, 197, 199.

Finally, two 'Reading review' slips list the technical articles submitted to Mr. Magès, one for February 1957 p. 193, the other for the fortnight from 15 to 31 October 1957 p. 201.

Context

This file is part of the major reliability project for the DS 19 and ID 19, launched by Citroën in 1955-1956 with their revolutionary hydropneumatic suspension. The stated objective of '100,000 km quality' corresponds, in the history of the brand, to the period when customer feedback on the first years of production highlighted failures in hydraulic components (high-pressure pump, cut-out valve, height correctors) — the key parts of the system invented by Paul Magès.

It should be remembered that the Manufacturing Methods department, where Magès worked, had the role of transforming usage feedback into industrial corrective actions, via technical notes distributed to engineers (Cadiou, Colombot, Bernard, Pelletier...).

Archivist's perspective

This file illustrates, better than many theoretical plans or notes, the daily work of Paul Magès once the hydropneumatic suspension was launched in series: it is no longer about invention but about industrial reliability — tracking leaks, quantifying defect rates, comparing variants of parts (Ø19 vs Ø18 rings, p. 202).

The density of the numerical tables (pressures, return rates, chassis numbers) and the circulation of numbered notes between Magès and his collaborators (Cadiou, Colombot, Bernard, Pelletier) testify to a quality monitoring organisation that was already very structured for the time.

It seems that this file directly extends the theoretical studies of the years 1943-1946 on suspension: it can be usefully compared with the Hydropneumatic suspension plans with differential interaction and automatic levelling and the Folder 'Theoretical study – hydropneumatic suspension 1943/44', which laid the conceptual foundations for what this 1957 file now had to make reliable on the road.