Endurance test monitoring of the 2 CV A12 with hydrostatic transmission (1963-1966)

In this document

These three handwritten sheets record, almost day by day, the mileage monitoring of the endurance tests of a 2 CV A12 equipped with a hydrostatic transmission, conducted on the La Ferté-Vidame track.

Beginnings and break-in (1961-1963)

The tests start "at the beginning" on 12 September 1961 with an odometer at 30,000 km p. 60. A pump break-in is noted, a "1 piston seizure" on the receiver followed by a disassembly-verification reaching 74,545 km p. 60, then a reset of the odometer on 15 January 1963 p. 60. Page 59 details successive break-in phases: break-in "at 85,478 Kgm", re-bored and re-serviced barrels (+21,847 km), a break-in with "BPIA" oil (+9,866 km), then a pump break-in "distributed with engine oil" (+46,000 km), with a total mentioned "on 13/12/63" of approximately 55,500 km p. 59. Two durations for a 24 cm³ pump are indicated: "LABO 90x1000 H" and "BEA 15x1600 H" p. 59. The mileages of two test vehicles also appear: ELV 640 (41,602 km, "fine-tuning") and ELV 724 (18,259 km) p. 59.

Incidents and continuation (1964-1966)

Page 60 then lists the events: an HP pump is replaced after the odometer was reset (30,529 km), a pump examination concludes it is in "Perfect condition" at 82,553 km (i.e., +67,734 km) p. 60, then a "seizure of the blocks [rollers?] on pump" is noted on 29 October 1964 at 113,082 km p. 60. The tests stop on 13 May 1966 at 188,334 km, due to "lack of driver" (p. 60, confirmed p. 61).

Page 61 resumes a more detailed chronology: on 15 September 1964, at 106,970 km, a report indicates a cumulative total of "approximately 200,000 km, of which 100,000 without [uncertain term]" p. 61. On 16 October 1964 (113,082 km), it is noted that "the car can drive, but difficult start" p. 61. Several bearing replacements follow: pump on 21 January 1965 (128,074 km), receiver on 16 April 1965 (146,251 km), receiver and gearbox output on 16 November 1965 (174,403 km), then gearbox output only on 4 March 1966 (184,815 km) p. 61, before the final stop on 13 May 1966 at 188,334 km due to lack of driver p. 61.

Context

The 2 CV, designed by Citroën before the war for rural motorisation, was commonly used as a rolling test bench for technical innovations before their potential application to other models. The hydrostatic transmission, a system replacing the clutch and the classic mechanical gearbox with a hydraulic circuit using a pump and receiver, was part of the research conducted at the Citroën Design Office in the 1960s-1970s to simplify driving. La Ferté-Vidame was Citroën's road test centre.

Archivist's perspective

This document illustrates, through the raw detail of the figures, the rigour — and the harshness — of endurance tests: more than 188,000 km covered over several years, punctuated by recurring pump and bearing failures p. 59-61. It seems that these repeated incidents, particularly on the receiver and gearbox output bearings in 1965-1966 p. 61, weighed on the final assessment of the system's reliability before its abandonment on this vehicle.

This monitoring finds a direct echo in the Mileage record of test vehicles with Hydrostatic Transmission (1960-1973), which probably synthesises this data over the long term, and in the List of tests for 2 and 3 CV vehicles equipped with H.T., which documents the continuation of the test programme after 1966.