Hard suspension
If you came from other Citroëns, most notably CX or DS, you might be disappointed. Citroën—to save room in the engine compartment but also for economical reasons, to share some components with Peugeots—redesigned the front suspension. The traditional layout had a triangle trailing arm (the suspension cylinders and the wheels attached at opposite corners of the triangle) while the new setup uses McPherson struts (the cylinders and the wheels attached at the same point). Later models (XMs and Xantiae) use a more sophisticated, computer controlled suspension system instead to ensure both comfort and stability. No matter what you try, the BX will remain inferior to these other Citroëns; sad but true.
However, if you drove another car and still you are not satisfied with the ride comfort of your BX, there must be something wrong with the car. Check the condition of the spheres, the level and condition of the LHM fluid (the fluid is neon green when new; a yellowish fluid has been thinned out). If you find the filter inside the LHM reservoir quite dirty, you should also flush the hydraulic system with Hydraurinçage. If necessary, adjust the height correctors, the wheel alignment and balancing. Actual failures in some suspension elements (stiff struts, worn or even collapsed rear arm bearing) can obviously disturb the usual comfort.
Even if the suspension is working perfectly, two factors influence the ride comfort. The first is the selection of tires. There are huge differences between tires and Citroëns ride most happily on Michelins. Not only because you have to be francophone to drive a Citroën but these tires are softer. Brij Dogra mentions in his Web site that Malaysia imported GTis with Dunlop tires to comply with local regulations. The dealer suggested that the clients should replace the brand new tires immediately with Michelin to regain the lost ride comfort (although the GTi, due to its elevated performance, has a tougher suspension to start with). Check the correct air pressure in the tires, too.
The second factor is less influential, although certainly more important than many drivers would think: the adjustment of the seats. The damping effect of the upholstery is desgined to work in harmony with the suspension. Worn seat cushions become thinner, losing their elasticity. They should also be adjusted correctly to give full thigh support which both reduces fatigue and gives the maximum damping. Certainly, this factor is less influential than the correct functioning of the suspension components, however, it does deserve some attention; not to mention that worn upholstery is detrimental to the looks of the car... The simplest solution is to find a seat cushion or back in a salvage yard (the front seats are interchangeable, so try to find a passenger side one, it is generally less worn than that of the driver). Alternatively, plastic sponge purchased in 1, 2 or 3 cm thick tables can be used to stuff the internal parts with excellent results. Cut the sponge to fit the available room tightly so that it won't start to move around by itself.
Checking the suspension
Run the engine in idle, height position in normal, wait for the height to stabilize. Push down the bumpers: the car body should go down softly about 10-12 cm and while you still push it down, after a few seconds, it should lift you back to normal position; then release it suddenly, then it jumps up and after a few seconds again, it should drop back to the normal position). If it is stiff, check the pressure in the spheres (including the main accumulator).
If the suspension is stiff, the car does not move at all or moves only a few centimeters, check your spheres for sufficient pressure. If the pressure did not drop below a minimum level, the spheres can be refilled with nitrogen. You should have all spheres checked by a workshop every 18 months. Quite often, when you already realise that the ride became less comfortable, the spheres can be too close to the limit. Checking the pressure is much less expensive than renewing the spheres.
The front suspension stiffness can also be a sign of wear of the front struts. Lubricating them with a small amount of LHM liquid might help. Locate the hole in the outer side of the front suspension sphere support (the upper end of the front strut) and pour some LHM into it. The lubrication might do wonders, however, be prepared that this does not solve the problem but only reduces the symptoms. You may have to repeat the treatment regularly (quite often, that is, up to several times a week) and find that it helps less and less until you finally have to replace or rebuild (see below) the struts.