If your car’s hydraulic system has not been flushed for years, it is probably overdue.
“TOTAL” now makes a flushing solvent specifically for Citroën hydraulic systems. Hydraurincage is the trade name. Basically, you drain the system as much as possible, install the flushing fluid. Then drive the car 1500 km to 5000 km, cleaning the filter on a regular basis. Then you drain the system, and install new LHM fluid.
I have had customers tell me of almost immediate improvements in the operation of the shifting system, the height correctors, and in the hydraulics in general.
Full instructions for use are available with purchase.