Citroën spent decades putting high-pressure hydraulics into cars, and Julian Marsh spent decades making sure somebody on the Web explained what all those spheres, pumps and green fluid were actually doing.
Visit Citroënët’s hydraulic-system archive
Citroënët dates back to 1995, when Marsh was helping build the Citroën Car Club website and realized he had enough material to create a separate site of his own. It began with a single reprinted article about the D Sport and eventually expanded into several thousand pages covering production cars, prototypes, concepts, commercial vehicles, books, memorabilia, articles and technical material.
The hydraulic section is one of the best examples of why that kind of enthusiast archive matters.
It gathers brochures, diagrams, historical articles and explanations covering the Traction Avant 15CV H, DS19, GS, GSA, SM, CX, BX, XM, Xantia, Hydractive systems and Citroën’s high-pressure hydraulic philosophy in general.
The system is strange until somebody explains the gas and fluid
Citroën’s hydropneumatic suspension uses a compressible gas as the springing medium and hydraulic fluid to transmit force, provide damping and control vehicle height.
An engine-driven pump pressurizes the system. Spheres containing nitrogen and hydraulic fluid replace conventional steel springs. Because the gas compresses while the fluid effectively does not, the system can provide extremely soft springing while self-leveling compensates for passengers and cargo.
That sounds complicated until the diagrams and descriptions walk through it.
The same high-pressure system could also power other functions. On cars such as the DS, hydraulics were used for suspension, braking, steering, clutch operation and gearchange. Later systems added electronic control through Hydractive suspension, while the Xantia Activa famously used hydraulic control to attack body roll.
Citroënët does not pretend the design was magic. The site also discusses drawbacks: low-speed harshness, road noise, pitching, motion sickness for some occupants and the odd behavior that can occur when height correction reacts to certain road shapes.
That balance is useful. Enthusiast sites are at their best when enthusiasm produces documentation rather than worship.
The archive is also a reminder of how durable subject-specific publishing can be. Citroënët began before Citroën itself had a website, according to Marsh, and the site has continued accumulating material across three decades of automotive and web history.
A modern owner searching for LHM hydraulics, Hydractive 3, DIRAVI steering, DS clutchless gearchange or Xantia Activa suspension can still land on a hand-built enthusiast site from the first years of the commercial Web.
That is exactly the kind of search surface CacheRat’s 1,967 Ancient Web Domains research list is meant to expose.
The cars were weird on purpose.
Thankfully, somebody documented the weirdness properly.