Test No. 220.657: dismantling of the ELV.230 hydraulic rear axle after 20,000 km

In this document

This is a report from the André Citroën Laboratory (53, rue Balard, Paris), dated with the stamp "DATE 11 | 3 | 52" with a handwritten note "2 MARS 1952" p. 97, addressed to "ETUDES" for the attention of "M. Magés" p. 97.

Purpose of the test

The document reports on the examination, after approximately 20,000 km of driving under load, of the hydraulic suspension rear axle of the ELV.230 test car (referenced "Suspension hydraulique - PVSC - ELV.230", test no. 220.657) p. 97-98.

Incidents during endurance

• At 12,000 km, replacement of both shock absorbers with a "new model"; the right (D) shock absorber had been found loose and "fallen into the cylinder" p. 97.
• At 1,300 km (or "1,000 Km", according to p. 98), dismantling of the cylinders to check the seals, in liaison with M. Magès; replacement of the rubber protective skirts p. 97.
• At 4,000 km, removal of the distributor due to an oil leak, left (G) connecting rod turned and then put back in place p. 97.
• Lockheed oil consumption: "530 cm3 for 16,400 Km" and "320 cm3 for 10,000 Km", given as a simple "order of magnitude" p. 97.

Examination upon dismantling

The two connecting rods were sent to M. Blanc for examination p. 98. The car was then reassembled with new skirts, cyanided fork and end piece, shock absorber valves without shims "in C3 C", and a new G connecting rod in O1 with a new ball p. 98.

Context

The ELV.230 is likely a Citroën test laboratory car, used to test the future hydropneumatic suspension in real conditions, a system whose plans were drawn up as early as 17 February 1944 (Hydropneumatic suspension plans with differential interaction) and which would equip the Citroën DS presented on 6 October 1955. These kilometric endurance campaigns were typical of industrial development before mass production, with the André Citroën laboratory on rue Balard being one of the manufacturer's test centres. This context is general knowledge, not derived from the document.

Archivist's perspective

This report concretely illustrates the iterative development work typical of Paul Magès' teams: each incident (loose shock absorber, leak, turned connecting rod) is noted, corrected, and then the part is sent back for testing with a modification (shims removed, cyanidation, new connecting rod). It seems that this document belongs to a larger set of tests and technical correspondence kept in the same folder, as suggested by the Summary of folder 41-59, dedicated to the hydropneumatic suspension and its evolution towards the DS.

The personal involvement of M. Magès, mentioned in the header and in the text ("in liaison with M. Magès"), confirms his central role in supervising endurance tests. Having joined Citroën in August 1925 at 17 and a half years old and a self-taught man who became deputy head of the Super-Control (autobiographical notes), he was then, in 1952, in the middle of the development phase of the hydropneumatic suspension which would lead to the presentation of the DS in 1955.