The same set up is on the rear arms and these are notorious for failing-----reason---- the rubber seals.
Being open to the elements, the seals are letting water and debris into the bearings and they can collapse.
I can supply seals made of a modern material called Ertacetal C, an acetal copolymer, it is an engineering thermoplastic.
This material, which cannot be eroded by the extemes of the elements, would be a leak proof fit to replace the rubber ones.
It is more resistant to hydrolysis. It combines low friction and high wear resistance with the stiffness and strength needed in parts designed to replace metal. Fatigue resistance and high strength are other attributes.
Please enquire about these plastic seals.
These tools can be bought or hired. A set of instructions on how to calculate and set the bearing preload will be included,
as there is a measuring device with the set. Another tool you will require, a digital vernier caliper, capacity at least 150mm.
New repair kits are available on the web, but do, please consider replacing the rubber seals.
A new complete kit will be in the region of £75 uk pounds. A cheaper option is just to renew the bearings and seals only. All the other
parts are serviceable, except for the seals. Also needed, maybe, are shims because Citroen used to sell different sizes of the thrust cups
[spacers] to achieve the pre loading but these are unavailable now, so shimming the thrust cup is the only option.