Front/Rear cylinder assembly E806-2346/2347 — hydraulic gear control (Védie, 1957)

In this document

This technical drawing concerns the assembly of two cylindrical units (marked E806-2346 and E806-2347) intended for a "Cde hydraulique de Vitesse — Pistons sur couvercle B.V." p. 26, i.e., a hydraulic gear control mounted on the cover of a gearbox.

Marking and pairing instructions

A handwritten note at the top of the drawing specifies: "Acid-etch the same number as Face F of E806-2-342/43. Pair the parts. Clearance = 0.1" p. 26. This instruction therefore imposes strict control of the clearance between paired parts, with physical identification via acid etching.

Parts list

The handwritten table details the components of the two assemblies (Front/Rear), with their quantities:

The cross-sectional sketch accompanying this table shows two superimposed cylindrical units (half-cylinders, pistons, pushers, flanges, seals, washers), with a mark "F" indicated at the center-right p. 26.

The technical title block indicates the mention "VALABLE POUR ESSAI 42806" (VALID FOR TEST 42806) and bears the signature of Védie, dated 5.5.57 p. 26, which confirms the precise dating of the document.

Context

This drawing is part of the development, at Citroën, of the hydraulic components that would equip the DS 19, presented in 1955 and whose commercialization continued during this period. The hydraulic gearbox control is one of the systems driven by the central hydraulic circuit, alongside the suspension and brakes, under the responsibility of engineers such as Paul Magès.

The name Védie, who signs this drawing, also appears on other documents in the same collection, suggesting a draftsman or engineer recurring in this type of technical drawing for hydraulic components.

Archivist's perspective

This document illustrates the level of industrial precision required for Citroën hydraulic components of the time: the requirement for a clearance of 0.1 (probably in millimeters) between paired parts, individually marked with acid, testifies to a concern for fine adjustment specific to sensitive hydraulic controls p. 26.

It seems that this drawing documents a development stage linked to a specific test ("Test 42806"), rather than a definitive production definition, which makes it an interesting witness to the development process rather than the finished product.

The thematic proximity to other parts of the collection dedicated to clutch release cylinders, such as the Clutch release cylinder drawing D314-02 or the Piston drawing DS 314-12, suggests a coherent set of work carried out in parallel on Citroën hydraulic controls during the 1950s.