1945 manufacturing schedules: Citroën suspension, starter-actuators and brakes

In this document

Title page

A handwritten page bears the inscription in red ink "Planning", the date "1945" in pencil, and three stacked numbers "43", "44", "45" next to a vertical red line p. 19.

"Suspension" schedule

The printed form Manufacturing Methods — Manufacturing Schedule covers the Suspension subject p. 20. It tracks the progress of several components:

• Electro-distributor 42401 B: test model dated 6.1.44, final model with 4 distributors per group, with the note "Finish if test model is good" p. 20.
• Suspension tube (method question): 11.4.44 p. 20.
• Supply pump entrusted to Mr. Guille p. 20.
• Suspension casing (air valves, valves, pistons): April 44 p. 20.
• Suspension cylinders: March 44 p. 20.
• Electro-distributor control: the bimetallic relay is noted as "not suitable satisfactory"; a wheel contactor dated 23/6/44 is awaiting a missing cover p. 20.
• Inflation fittings and 3-way fittings: 9.5.44 p. 20.
• Test bench: test bench itself (19.2.45 then 14.5.45), compressed air installation (18.4.45), endurance tests entrusted to Perrier, assembly to measure the friction of the suspension piston seal (11.5.45) p. 20.

"Starter-actuator" schedule (cold start)

Second form dedicated to the Starters - Actuator, Cold start subject p. 21:

• Rubber actuator 4227A: dated 16.11.44 p. 21.
• Rubber silentblock tests (resistance, flexibility, endurance) p. 21.
• Assembly and development of three devices: 18/12/44; assembly on a TPV engine with laboratory tests and silentblock endurance, note "Assembly to be studied" p. 21.
• Direct hand actuator 4227A E: mention "test performed" and bench clutch tests (13/12/44), then roller freewheel tests (12/2/45) p. 21.
• A reflection on various "starting solutions" is mentioned: electro-rubber starter, electro-inertia, hydro-pneumatic, with the remark "Report on the question... to be finalized" p. 21.

"Brakes" schedule

Third form, Brakes subject, reference "E 45.7" p. 22:

• Brake metering valve: adaptations on TUC (Meignan, 24/11), TPV (6.11.43), HZ front/rear, P38 front/rear (reference to "Servo-Brake") p. 22.
• Final study of the type G metering valve (Pin) and comparison with type H, development of type H by Meignan p. 22.
• P38 servo-brake and trailer braking: BP pedals and master cylinder, vacuum servo with HP accumulator cylinder (Perrier, 20/4-29/6), distributor (Meignan, 16.4), assembly of metering valves (2/5-15/5), general installation plan on P38 (Perrier) p. 22.
• Truck-trailer connection: assembly of metering valves on trailer, general installation plan p. 22.
• Brake shoe clearance adjustment: friction solution (Perrier, 28.3) and positive ratchet solution p. 22.

Context

These schedules date from the period when Paul Magès was developing, within the Citroën Manufacturing Methods department, the technical components that would lead to the hydropneumatic suspension — the future signature of the DS presented in 1955.

The immediate post-war context explains the concern for "cold starters": the engines of the time, particularly on utility vehicles and the future 2 CV, had to be able to start in extreme cold without a reliable battery, hence the research into mechanical or pneumatic actuators.

The standardized forms "N° 752/a - 8-44" testify to the industrial organization of Citroën, where each study is followed month by month according to a color code (preparation, studies, tooling, tests).

Archivist's perspective

This triptych of forms is valuable because it shows, on a scale rarely documented, the simultaneity of the projects led by Magès' teams in 1944-1945: suspension, starters and brakes advance in parallel, with their own managers (Guille, Perrier, Meignan, Pin) and their own delays (the famous "missing cover" of the wheel contactor, p. 20).

It seems that this document allows for more precise dating of certain milestones already known from other pieces in the collection, such as the hydropneumatic suspension plans with differential interaction of February 1944, or the suspension cylinder plans of January 1944 — the progress of which is noted here as "March 44" p. 20.

The "Brakes" schedule p. 22, less often associated with Magès in known archives, reminds us that his team did not work in isolation on the suspension but participated in a broader effort to modernize Citroën braking, probably in connection with the 1945 BEA work programs.