Suspension, Hydraulics and Steering

General troubleshooting

First of all, take a peek into the LHM reservoir. If the fluid is yellowish, it is old, damp or even diluted with engine oil. If it is dirty, it was probably never ever changed. Proceed to flush the system and renew the LHM.

Start the engine and leave the height in the normal setting. If it takes more than 30 second for the care to rise to the normal height, with the pump working continuously, the pump might be weak or the inlet hose split. If only one end of the car rises, the corresponding height corrector is faulty (often only stuck with dirt or disconnected). If the car rises but falls again, the linkage to the height corrector (or the corrector itself) is suspect. If the STOP light on the dashboard stays on more than 5 seconds after you start the engine, there might be problems with the main accumulator, pressure regulator or the high pressure pump but it is also possible that the LHM level is simply too low.

If the car rose normally but later the pressure regulator cuts in (this is the characteristic clicking at the front of the car) more often than once in every 20-25 seconds, the main accumulator or other components are suspect.

If everything was OK so far, look into the reservoir once more, with the engine running. If you see any significant amount of LHM returning to the container, the steering or the brake compensator valve is likely to leak. Small amounts of returning LHM indicate possible problems with the pressure regulator or the main accumulator.

Turn the steering wheel from side to side (on models with power steering). if the pump runs continuously while you do so, the main accumulator or the front spheres are suspect. The power assisted steering need copious amounts of LHM, so any deficiency in the supply will be instantly obvious when trying to turn the wheel. But if the heavy steering occurs with the car rising all right, the flow distributor is probably clogged. Without the car properly raising, however, the same heavy steering points to the high pressure pump (or its drivebelt slipping). The condition of the main accumulator does not influence the operation of the power steering.

Visit all four corners of the car: press down the corner and release it. If it feels solid without any bouncing, the sphere in that corner is flat. If it is soft but bounces a lot, the shock absorver valve is worn. The correct behavior is soft but with damped bouncing. Sit on the front bumper: the front must sink immediately and rise back to normal height in 10 to 20 seconds. Get off the bumper: the front will jump higher but return to normal in a while. Repeat the test at the back as well. If it does not behave as described, check the height correctors or their linkage. As the correctors are beneath the car and even slightly moving them can cause the car to drop in an instant, it is absolutely imperative to do this (and any other suspension work under the car) with the car very safely supported on axle stands, car lifter or ramps. Make sure that nobody, especially children, can sit into the car while you are working under it (it is best to lock the doors).

Set the height lever in the cabin to the lowest position. The car will sink but it if clonks at the end of the travel, the stops are worn. Then set the lever to maximum, if it takes more than 20 seconds to reach the high level, you can suspect the pump or bad setting of the height corrector—but first, check that there is enough LHM in the system. If the pump works with a loud rattling noise, this might also indicate the insufficient level of LHM.

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.

Rebuilding the front struts

You will need a seal kit (there are two such kits, part number 95 650 941 only contains the main piston seals while part number 95 597 221 has all necessary seals) and a slide bearing (part number 96 004 372) to rebuild each front strut. Apart from some common tools, you will also need a 36 mm socket wrench or spanner; a 18 inch (45 cm) "Stilson" pipe wrench; a bench vice (or the pipe wrench at least); a 6 mm (¼ inch) diameter steel bar or pin punch of about 8 inches long; a propane-butane gas blowtorch (not an oxy-acetylene one) or another heat gun; and some Loctite or similar thread lock.

First, clean the wheelarch by hosing it thoroughly with water and let it dry overnight. To remove the struts, jack the car up, support it on stands and remove the roadwheels. Depressurize the hydraulic system; there is no need to remove the spheres or undo any screwed pipe connections. Put a plastic bag over the brakes and secure it in place with a piece of wire.

Next, pull off the rubber cap on top of the strut. Loosen (but not yet remove) the nut with the 36 mm socket and a big tommy bar. Undo (but not yet remove) the pinch bolt at the bottom of the strut mounting (by the wheel) and the three strut locating nuts on the inner wing. Now remove all nuts and bolts undone and pull off the two rubber return hoses from the pipes in the wheel arch. Gently tap the top of the strut so that it moves down and becomes loose in the sphere support, then grasp the base of the strut and twist it loose from the lower clamp. Finally, remove the strut assembly from under the wheel arch. Note at this point that the sphere and its mounting should be untouched and left resting on the inner wing.

Next thoroughly degrease and clean the whole assembly and seperate the rubber boot/top mount from the strut body. Don't worry about any dirt entering it at this stage, because it will be stripped and cleaned anyway, and a clean exterior makes it so much easier to work on.

To dismantle the strut, grip its body in a vice and using the pipe wrench undo the brass slide bearing on the top of the strut (the one screwed into the top of the strut body, not the smaller brass collar fitted onto the shaft!). If you prepare two halfshells fitting nicely over the strut body (just use 4-5 inches of a 2 inch waterpipe separated into two halves), you can grip the strut in the vice without damaging it. The thread is a normal right-hand thread, but it might be so tight (especially as it is locked with Loctite) that you will have to use a gas blowtorch on it for about 30 seconds or so to help loosen it. There is about an inch of fine-pitch thread there, so it will take a bit of turning to get it out. Carefully drain any remaining LHM out of the strut while holding the parts together, finally, withdraw (carefully! they will be quite loose when they come out!) the internals which comprise of spacers, bushes, piston rods, and bump stops, and note (possibly by making a sketch) which order they were assembled in.

The steel nut at the bottom of the shaft has to be undone as well to fit the new slide bearing, and this one will be very tight, too, so the blowtorch might help again, combined with the 6 mm pin punch (through the oil hole) while gripping the nut in the vice.

Once everything is out, thoroughly clean and degrease it all, including the inside of the strut body, as there will be loads of contamination in here. The rubber return hoses might remain attached all along but if they need replacing anyway, this is a good time to do it.

Before re-assembling, apply a thin coat of silicone grease (grease, not silicone spray!) to all internal working surfaces. Compare the removed and the new parts to see where the wear was. All the parts you need will be in the two kits listed above but the most important ones of all are almost hidden: after removing the smaller steel piston rod from inside the main strut shaft (the medium sized piston rod, not the smallest one at the very bottom), look inside the bore of the main piston shaft and you will see a small, white teflon sealing ring a little way up the bore. This is the main piston seal, and when it is worn it is the cause of all the hesitation and jumps when raising or lowering the suspension.

If you find the piston rod itself having stains or even rust, you might consider polishing and cleaning it very thoroughly. Use a thinner first and lots of elbow grease. Then fill the pits with hardening plastic putty and finally polish it until it is really smooth and even.

The creaks, groans and LHM leaks in the suspension are caused by wear in the bronze slide bearing and its rubber seal, but if this little ring is worn, the pressurised LHM just leaks past it and into the return system (this is the reason for both poor suspension performance and the return line popping off easily). So, remove the old seal carefully, taking care not to damage the bore (use a soft tool, toothpicks, for instance, are excellent), and fit the new ring into place very carefully. This job is a little bit fiddly and awkward, but take your time and use a soft plastic or wooden tool (old toothbrush handles are perfect) to push it into place and seat it properly.

When fitting the new bronze slide bearing onto the piston shaft, you might need to use a tiny bit of moly or silicone grease on the felt wiper seals to help them slide smoothly on. It's very easy to kink these seals and pull them out of their seats when fitting the bush on, so observe them as you do it. The shaft should not stick, even lightly, when fitted into the slide bearing, so if it does this, it probably means that the felt wiper has come off its seating. Refit the new rubber bump stops, bushes, and sliders in reverse order, and use Loctite thread lock to secure the steel nut on the bottom of the piston shaft.

When re-assembled, pour about 20 cc of new LHM into the strut to lubricate it, and assemble the parts inside. Use Loctite to hold the slide bearing in place while you screw it back in.

Peter NEILL

If the strut fails completely, it leaves lots of metallic debris in the hydraulic system. Flushing and replacing the LHM is required in this case.

Rebuilding the flow distributor

Put the distributor unit flat on a surface, so that the side with the two conduit sockets points upwards and the pressure adjustment screw (between two plugs on the side of the unit) is to the right, the side with the three conduit sockets will point downwards then.

Take out the top right plug, followed by the bottom left one. For each plug, you have to press it in (expect quite a lot of resistance) and while holding it depressed, get the retaining spring on the inner side of the opening out. The plug will hardly come out more than a few millimeters but as there is a spring behind it, you can bounce the plug inwards and let it pop out by itself. It may take several tries. And when it does come out, be prepared for a rather strong spring to follow it. Be sure to have the whole unit thoroughly cleaned before you start, using a small brass brush on the plugs and spraying it with a rust remover or screw loosener—any debris along the edge of the plug will prevent it from coming out.

Go on with the top left plug and remove its retaining spring as well. Then, using a blunt pin or bolt, push the piston inwards, on the side where the strong spring came out. The top piston will pop out the other end, pushing out the top left plug as well. Then comes the real problem part, getting the bottom piston out. The easiest way to accomplish this is to use compressed air. Using a hex key, unscrew the retainer found in the bottom right conduit socket (on the side with the three conduits, closest to the pressure setting screw).

There are a restrictor washer and a small plastic filter beneath it. The filters—there are two of them inside the unit—will usually be damaged thus you have to use the new ones coming in the repair kit. Clean the hole with compressed air, plugging the adjacent one with your finger. You could use some cleaning fluid as well, including even water, but in this case you have to dismantle and dry thoroughly everything to avoid damage.

The pressure will slowly push the lower piston out through the hole opened when you removed the bottom left plug and the spring behind it. The best way is to give it a couple of blasts rather than a continuous flow because that will dislodge the bottom piston, which is frequently barely able to move due to the crud deposits.

After having done that, turn the unit so that the conduit hole you removed the filter from faces down, and tap it on the opposite side. That should dislodge the bottom piston end stop, a small cylinder with slots and holes, which will fall out the hole where the filter was in. Once you have done that, you may push in the right bottom plug, take out the retaining spring and then push the plug out by inserting a blunt object through the hole where the bottom piston came out from. Do not try to push the bottom piston out through with the bottom right plug end, as the hole is not finished to the right tolerance beyond the end stop, so you will be damaging the piston pushing it through that way.

You can now remove the second filter from the top right conduit socket (the side of the unit with two conduits, nearest to the pressure control screw), using a hex key to remove the retaining nut inside the hole.

Mark the relative position of the pressure control screw and its collar. Then loosen the collar, but not more than about a quarter to half turn. Now you can unscrew the screw together with the collar on it, do not remove the collar as that will upset the relative positions. There is a spring, a plunger and a ball in the hole that you will be opening. On later units, you cannot gain access to the screw, because it's covered by a pressed-in plug. If you find one, leave it alone. Besides, you can skip this whole paragraph, this part of the distributor is unlikely to have any deposits.

Carefully wash all the pieces. Pay particular attention to removing dirt and rust from the inner walls of the openings the four plugs go into. When you are done, douse everything liberally with fresh LHM to prevent rust formation.

The repair kit contains four new o-rings (don't even think about reusing the old ones, they will leak) and two new filters.

Examine the pistons carefully. If they are shiny on one side but dull on the other, it might be time for a new flow distributor, because this condition means uneven wear—they will never seal properly again. However, experience has shown that this is not a big problem. In some cases the power steering pressure will have to be adjusted slightly higher to compensate for internal leaks in the distributor.

Examine the perpendicular holes at the end of the pistons. If you look into them, you will find a screw with a hexagonal hole. You can use a hex key to unscrew the screw. Between this item and the rest of the piston body is a thin restrictor washer. There are two possible problems here: the screws can be extremely hard to unscrew. The way to do it is to insert a hard pin through the hole in the piston and use a long-end high quality hex key (looks like an L with both legs of equal length). Keeping the piston in screw loosener liquid overnight may be a good idea. The pins used must be round and unbendable. Of course, you never want to put the piston itself into vise clamps or something like that—the surface of the piston is very hard, but it must not be damaged or you can throw the whole thing away.

A more serious problem can be that debris in the LHM, and the disintegrating pieces of the two small plastic filters can blow out the restrictor washers which are quite thin. Look at them carefully, the typical problem is that there will be cracks from the hole in the middle, going outwards. In really bad cases a whole section will be missing. In any case, these need to be in good condition or the flow distributor will not work properly. If they are damaged, they need to be replaced. As far as I know they cannot be purchased separately, you have to take them out of a replacement unit.

If you plan on making one good unit out of several, never mix up the pistons and the body. One set of pistons always goes with the body they were found in. Choose the body and pistons where the pistons show the least wear (they are not shiny but very smooth and slightly dull).

Re-assembly is, as usual, in the reverse order, except that the end-stop for the bottom piston and the filters and retaining nuts and restrictor go in first. Then goes the pressure valve with its ball, plunger, spring and screw with collar. The plunger goes short end in, long end with spring out. Remember to return the screw and collar to their proper places. The screw is turned in as far as it needs to go, then the collar is tightened while keeping the screw immovable with a hex key (steering assistance increases by screwing the screw in, decreases by loosening it—tamper with it at your own risk!). Then come the pistons: the long (top) one goes in so that the end with the spring is to the right, the other end with the restrictor to the left. The short (bottom) piston goes with the restrictor in, spring out. Do not mix the springs for the two pistons and the pressure screw!

Now come the plugs. Put on the new o-rings, push them in and latch in the retaining springs. You'll have fun with the ones with the spring behind, but that's life. The bottom right one will go in deep and of course will not come out because there is no opposing force—that is, until the pressure pushes it out. Even so, do not push it inwards too much, just enough to put in the retaining spring. Put in all new conduit gaskets if at all possible.

Željko NASTASIĆ

Rebuilding the pressure regulator

Release the hydraulic pressure pressure and undo all the conduits leading to the pressure regulator (have a rag handy, there is going to be a lot of LHM leaking out).

Remove the regulator coupled with the main accumulator. If the retainer ring does not come out easily from the regulator, try to use some special tools (looks like a miniature crowbar) and a jig to press the plug inside and you might be able to take the ring out without any further intervention. This ring holds a lot of pressure, hence it is very strong and will not be too willing to come out. Get something hard and pointed, and a small hammer. Press the plug in (a C-clamp works great for this), 1 mm will suffice. Be sure to keep the small missing section of the ring, where the ends meet, free of dirt and obstruction. Now wedge your pointed tool against one end of the spring and give it a tap with the hammer. If the ring moves, you can probably dislodge it this way.

If not, you will have to use more creative measures. Put some sort of plug into the conduit holes to avoid dirt getting inside. You need a good hacksaw or even a grinder to make a narrow incision radially, at an angle, where the blue part is shown. Before you do that, notice that the spring has a small section missing. Your hacksaw or grinder will have to grind right into that missing section, until you practically touch the 45 degree beveled outer edge of the plug. After you have made the incision, you need to use the hard pointed tool with the hammer to get even just a little bit of the ring to cover the incision. Then, you put something pointed, such as a large needle or even a nail, into the incision under the ring, and pop it out. After that you can get it completely out with a small flat-blade screwdriver or similar tool. Of course, you need to press the plug in to be able to get the ring out. However, do not pop the spring out just yet.

Clean the outer surfaces thoroughly, be careful not to get cleaning fluid inside yet. Use a brass wire brush or old toothbrush to get all the rust and debris out of the inner lip and around the spring that holds the plug in, otherwise it will be very difficult to get the plug out.

Separate the accumulator from the rest of the unit. Have a clean glass or jar filled with gasoline handy before proceeding with the next step. You'll also need a 6 mm socket wrench.

Remove the rear plug carefully, its spring is very strong. If it doesn't come out on its own, do not remove whatever tools you used to press it in with, just loosen it and tap on the regulator a few times, or even on the plug. It should eventually come out. Put the parts into the jar, everything except the O-ring, a new one has to be used. You should have the plug, the spring, a small part like a plate and possibly one or more thin rings.

Peek into the other end of the regulator, where the accumulator were. There is a small piece of metal inside secured by a 6 mm bolt, partially covering two holes. Take it out carefully, do not turn the regulator over, otherwise you will lose the ball. When you have removed the bolt, cover the opening with your hand and turn over the regulator. A bolt, a small piece of sheet metal and a small ball will land in your palm. Also, you might get the cut-in piston, too, but this is unlikely because the dirt will probably hold it in its place. Place all parts into the jar.

Push in the bottom end (where the plug was) of the piston, it should pop out the other end sufficiently for you to take it out. Again, put it into the jar.

Unscrew the two hex bolts, a little at a time to maintain balance of the plastic cover, opening up the cut-off spring, plate and piston assembly. Note that there is an O-ring under the plastic. Take all the parts out, including the thin rings at the bottom of the plastic cup, and put them into the jar. Leave the plastic outside.

Now you should be able to carefully pull out the piston with your fingertips. If you have to use pliers, do it gently (that part of the piston does not touch anything so scratches are not a problem). Remove all the conduit seals from inside the holes, you will need new ones anyway. Remove the pressure release bolt as well but be careful, there is another small ball inside and it is different from the one from the cavity where the accumulator goes, don't mix them.

Clean everything that remains thoroughly with gasoline or brake pad cleaner. When you are done, immediately douse everything with fresh LHM, if the housing is exposed to air, it will rust right away. Pay special attention to the hole where the little ball was, there should be no deposits left there. Clean the plastic parts with detergent and water, then dry them thoroughly. Clean all parts in the jar similarly with gasoline or brake pad cleaner. Be careful to get all deposits off the little ball. When you are done, get a small container and fill it with fresh LHM, and submerge the two pistons and the O-rings in it.

Now you can start re-assembling everything. Get a thin piece of brass first. When you put the ball back into its place, hold it there with the brass, and give that a good tap with a hammer. Get the ball out, put it back in, and do it again. Remove the ball once more. Pour some fresh LHM into the accumulator side of the regulator, replace the ball and while holding the other end shut with a finger, slide in the thick piston. It should go in without any resistance at all. Now put in the piece of sheet metal and secure it with its bolt.

Assemble the cut-out piston assembly. Douse the hole with LHM before putting the thin piston inside and remember to replace the O-rings. Don't worry if the thin piston slides way into the hole, it is more or less self-adjusting. The spherical end should stick out of the hole. Again, when tightening the hex bolts, do each a bit at a time, keeping the plastic cup parallel. Assemble the cut-out parts, starting with plate, spring and plug. It is very inmportant to replace the O-rings with new ones, otherwise the regulator will leak. Douse the inside rim with fresh LHM to help the O-ring slide in without getting pinched. At first, it is enough to just aim the plug in the right general direction. It is very difficult to press it in by hand!

Press in the plug slowly, and at the right moment, slip in the ring. Put the other small ball and pressure release bolt back into their place. Refit the accumulator and refit the whole unit to the car. Start engine and tighten the pressure release bolt.

Željko NASTASIĆ

Recharging or renewing?

A sphere is only as good as the neoprene membrane that contains the pressurized gas. Occasionally, the interface between the membrane and the retaining plate inside the sphere is to blame for leakages, but usually any problem is associated with the membrane itself. Like anything that's under constant flexing, it'll break down over time.

When the internal pressure drops below about half the original, the reduced gas pressure could allow the membrane to start smashing against the inside surface of the sphere, adding to the already high stresses. If there are any imperfections on the inside of the metal, that's a further detriment to the membrane's life expectancy. Several people who recharge spheres won't recharge them once they've dropped below about half pressure because then the incidence of failure is too high—leading to wasted time and gas, as well as irate customers.

However, many spheres seem to go on indefinitely—they lose very little pressure over many years' use and then remain in good working order for many more years after being recharged. On the other hand, some spheres don't last any time at all (I had two new rear ones from a factory-installed bad batch of neoprene that lasted one or two days before losing virtually all their pressure, leading me on a wild goose chase suspecting everything else in my car other than the new spheres).

On balance, I say you are far better off recharging for as long as the spheres retain their pressures reasonably well. Once they start dropping pressure too quickly, chuck them and buy new. What helps greatly in all this is access to a pressure tester—a simple device using an old hydraulic jack, a pressure gauge and an old Citroën cylinder into which to screw the sphere to be tested. Then it's an easy job to test your pressures on a fairly regular basis and thus keep tabs on what's happening. You can also tell by the ride quality of the car and how soft it feels when you push down on the bumpers, but the testing rig gives you definitive numbers.

Adrian HARPER

Theoretically, the best thing to do would be to keep the spheres always at the original pressure. This is of course not feasible but if you, say, refill your spheres as soon as they lose 10-15 bars of their pressure, you'll be close. The point is to refill them early on, long before they even start to go flat. First, when a sphere goes real flat, your chances of successful refilling diminish (you will usually be able to refill them but they won't hold the pressure long). Second, if you allow them to drop their pressure, this means that you have used your car for quite some time with reduced pressure—bad for comfort and other parts in the suspension. So, from a technical point of view, frequent (every 12 months or less) refilling is the best solution, always keeping the pressure in the best and most comfortable operating range and ensuring a long life for the spheres.

However, finances often say different. If you don't have easy access to pressure checking and refilling equipment and garages doing it charge you more or less the same for refilling as you would pay for new spheres, you probably want to go for new spheres, anyway. But you certainly will wait longer before replacing the spheres, you'll let them go flat before you do (I don't think you would want to replace a sphere when it is only 10-15 bars below original).

To summarize, to refill the spheres successfully, you should do it much more often than you would consider changing the spheres acceptable. Failing that, there is not too much point in refilling.

Removing a suspension sphere

The proper Citroën workshop manual method—in contrast to what the Haynes manual says—is to loosen the suspension sphere with a chain wrench ¼ turn while the system is still under pressure. Be very careful and absolutely sure that it is really only by a quarter of a turn. The pressure in the system is huge (the force behind the sphere can reach more than one ton, that is several thousand pounds), so opening it up with all that high pressure liquid behind it can be extremely dangerous.

Sometimes this is easier said than done. Strong chain wrenches usually do the job but a cold chisel and a hammer can also be used to hit the sphere tangentially. This leaves marks but generally breaks the corrosion between the sphere and its support. And here is a nice idea from Alasdair MACKINTOSH: "My home-made sphere remover consists of a large jubilee clip and a piece of old bicycle inner tube. Choose a clip that's big enough to go round the sphere. Wrap the piece of inner tube round the sphere, then fit the hose-clip round the sphere, along its 'equator'. Tighten up the clip, then place a big screwdriver in the screw, and whack the end of the screwdriver with a big hammer. Make sure that the inner tube rubber is clean and dry, and does not have any remnants of talcum powder on it. Also make sure that the screw head on the clip is facing the right direction to loosen the sphere when you put the screwdriver in its head."

Then, undo the pressure release screw on the pressure regulator (in front of the engine, at the bottom) by 1 to 1.5 turns (don't remove it!) and move the height control lever in the cabin to the lowest position. Now you can loosen the sphere completely.

When you fit the new sphere, grease the mating face of the support and tighten the sphere only by hand as recommended by Citroën. You will be able to remove it easier next time.

Replacement spheres

To start with, these are the spheres originally fitted:

It seems that no matter how comfortable the suspension of Citroëns is compared to any other car available, we are never completely satisfied with it. Many of us have tried various modifications to make it just a little bit more comfortable. A very simple and straightforward way to try this is by using different spheres than originally fitted. Changing the pressure of the spheres is likely to ruin the stability and roadholding but playing with the restrictor hole diameter can be more rewarding (in fact, the so-called comfort spheres, which can be bought for some Citroëns—XMs for instance—, are the same: larger restrictor hole diameter, nothing else).

If you examine the tables, you'll see that Citroën has modified the suspension of the BX to be stiffer during the years of production. Also, sporty versions like GTi or GTi 16V always started with firmer suspension. However, the suspension elements fitted to various BX models are interchangeable in the sense that, if you happen to have a firmer setup, you can safely change it for a more comfortable one. Roadholding might be affected in a way: for instance, if you replace a GTi 16V with TRI suspension elements, you will naturally lose the sporty handling the car was designed for; but it won't be dangerous, it will handle just like the TRI always did.

The only other suspension element that goes with the sphere are the rubber bump stops inside the front strut. Some struts have two such stops, others have one, according to the sphere volume fitted. If you replace the sphere, you might have to take out one of those buffers, too.

For instance, my 19 TRI Break was originally fitted with 500 ccm/55 bar/1.65 mm spheres at the front. Last time I had to touch the spheres, I fitted 500 ccm/55 bar/1.80 mm ones, the ones actually used on the same model a few years earlier.

You can observe the same pattern on the rear spheres as well. On the Breaks, for instance, the rear sphere restrictor hole was reduced in the same way during the years. If you retrofit the earlier ones, the suspension will be better.

Fast sinking of the rear end

The LHM returns to the reservoir via the brake distributor valve. If that cannot keep the pressure in the rear suspension but lets the fluid return, the rear end will sink fast. This is not a problem in itself: if the car sits up fast when started, has no other suspension or braking problems, there is no need to rush to the workshop.

There are quite a few other factors influencing the sinking as well. Flat rear spheres, old LHM and hot weather also make it sink faster.

Flushing hydraulic system

There is a product called Hydraurinçage (sometimes also called HydraFlush, the French name is pronounced as \id-ro-ra[n]-sa'zh\ or, more precisely, using the IPA phonetic symbols: ɪdrɔrɛŋ'sɑ:ʒ). It's a special cleaning liquid manufactured by Total, orange in color; your nearest Citroën dealer is sure to have it on stock. The price is more or less the same as that of the regular LHM.

To flush the system, you have to drain the old LHM, clean the filters, fill it up with Hydraurinçage, drive the car as usual for 3-5000 kms, then drain the orange fluid, clean the filters again and refill with fresh LHM.

When replacing the fluid, don't forget to drain the brake circuits as well: put the car on axle stands. On the highest suspension setting, remove the wheels. Let the engine run and ask a helper to press on the brake pedal. Let the fluid run from each brake caliper bleeding screw (put a transparent hose onto the screw) until the new fluid comes out (as already mentioned, LHM and Hydraurinçage have different colors).

There is another trick you could try first: calisthenics. Go up and down with the suspension for fifteen minutes, from the lowest position to the highest and back again (standing still, naturally). This makes the LHM circulate quite a lot inside the system (much more than during regular driving), which in many cases will free and mobilize the dirt in the system bringing it back to the reservoir where the filter, hopefully, catches everything. If the suspension or the power steering did improve after this exercise, there was dirt in the system, so check and clean the filter in the reservoir (or even replace the LHM).

Don't be alerted if the comfort of the car changes suddenly. It might become softer or harder with the flushing fluid, it might even change its behavior during the kilometers you drive. Even when you replace it again with fresh LHM, don't expect it to normalize immediately, give it another two or three weeks before you judge how effective the flushing was.

If the LHM was regularly replaced and there was no strut damage (which might have sent send metal debris into the system), flushing is usually not necessary (but if you're unsure of the earlier life of the car, it might help). On the other hand, be prepared that flushing might dislodge some dirt that used to seal otherwise leaking elements, so you might need some repairs after the flushing. Not necessarily, but don't be alarmed if some leaks surface. Even if this is the case, it's not the flushing that causes these problems, it only reveals them sooner than normal wear and tear would.

Creaking front suspension

The front struts have a rubber seal around the piston, and when the piston gets dry, the rubber grips it a little. Put the suspension up to full height, lock the steering one way (then the other for the other side). On the piston, there is a rubber protection gaiter. Lift this up and apply a small amount of penetrating oil or LHM liquid to the shiny arm.

Martin GUTKOWSKI

Fast ticking

The main task of the main accumulator (a sphere in front of the engine, similar to the other four; look down between the engine and the radiator) is to maintain the normal pressure in the system. The hydraulic fluid is drawn from the reservoir by a pump operating continuously. The accumulator sphere maintains the pressure for some time but it drops slowly as you use the brakes or the power steering. Once it drops below a minimum level, the pressure regulator (a valve the accumulator sphere is mounted on) opens and lets some fluid enter the accumulator, then closes again as soon as the necessary pressure is restored. The ticking sound comes from the operation of this pressure regulator. As this main sphere becomes old, its ability to retain the pressure reduces and the pressure regulator must open more and more frequently to restore the lost pressure, up to a point when it is nearly always functioning (every 1-2 seconds). Apart from the bothering noise, this puts a heavy strain on the hydraulic pump itself.

If the residual pressure in the accumulator is not yet below a minimum level, it can be refilled, otherwise you have to replace it with a new or reconditioned unit.

But even if the main accumulator is healthy, the system might tick frequently. The cut-in and cut-out pressure of the pressure regulator might be out of tune. Check if a lot of fluid is coming from any of the return pipes on top of the reservoir, especially the thick one from the regulator—this would point to a faulty regulator. Any other failure allowing the fluid to escape from the accumulator and leak back into the LHM reservoir also makes the hydraulics tick fast.

To locate the problem spot more precisely, jack up the car on safety stands and with the engine idling, remove each of the four small diameter return hoses, one at a time, from the reservoir. Have a clean jar and rags ready for LHM spillage. Hose #1 is the one towards the front of the car, #2 comes next, #3 is the right angled hose (do not remove the hose itself, there is a little ball inside you would lose, remove the plastic coupling element instead), and #4 is the last one (the remaining two are the high pressure lines, don't remove them!). Note which of them are returning LHM fluid.

Return hoses		Reason
	#1	front and rear cylinders
	#1 but not #3	rear cylinders
	both #1 and #3	one or both front cylinders
	#2	safety valve, front/rear height correctors, power steering cylinder (the safety valve can be tested by removing the hose at the valve itself)
	#3	front cylinders ventilation
	#4	brake valve (plus operational return, with brake pedal pressed and released)

The ticking interval should finally return to about one minute (or more) between ticks (engine idling, nobody sitting in the car). However, older cars quite commonly have an increased ticking frequency (5 to 10 seconds between ticks). Although this does signal that some parts of the system are worn, the car may perform well for quite a long time, at most with minor repairs over time.

Stiff power steering

Check the level of the LHM, clean the filters in the reservoir and renew the fluid if necessary. If the filters were very dirty, you should flush the system. If this does not help, you can suspect some failure in the hydraulics like a flat accumulator sphere, faulty pressure regulator, or even a faulty hydraulic pump.

The system is designed to maintain safety: if the pressure drops, the steering goes first, then the suspension so that you still have brakes until the last drops of LHM. And as the steering requires copious amounts of pressure, even a slight pressure drop might make the steering stiff or default to mechanical instead of power steering. This signals an ongoing deterioration of one of the components involved, so if the stiffness cannot be eliminated by simple cleaning, you'll have to replace some parts sooner or later anyhow.

Wobbling steering wheel

There is a hard rubber bush at the bottom end of the upper steering column, just above the universal joint. If the upper shaft is not correctly adjusted, this bush can work itself out of the column. When it becomes loose, the whole upper shaft and the steering wheel itself will wobble.

To gain access, remove the lower steering column cover. Loosen the bolt of the universal joint and turn the ignition key from the locked position. The upper shaft with the rubber bush can be pushed back into the column, possibly by tapping it slightly with a hammer. If you remove the column (by removing four nuts and disconnecting the connectors of the stalk switches), it might prove easier to drive the shaft and bush back into position. After driving it back, fasten the universal joint.

If the upper shaft is correctly adjusted, the bush will remain in its proper place, hence, if you had to put it back, your steering wheel was set too close to the dashboard. There should be about 4-5 mm clearance between the steering wheel and the upper cover. If it is significantly less than that, especially if the wheel scrapes the cover when turning, the bush will pop out of its place in due time.

Clanking steering wheel

A standard cause on older cars is the flexible coupling between the lower steering column shaft and the steering unit. This is a rubber disk (so-called Hardy disk) fortified with metal. Check it at least once a year to prevent the failure of the steering system which could be, needless to say, very dangerous. The coupling can be seen from the engine compartment, down behind the engine, just in front of the bulkhead, where the steering column shaft enters the engine compartment.

It's easier to replace it with an inspection pit or car lift, however, it can be solved with the car jacked and supported safely on axle stands.

Remove the nut (12 mm) and bolt (5 mm Allen) securing the flexible disk to the axle of the steering pinion. To do that turn the steering wheel to a position where the head of the bolt becomes accessible (ask an assistant to turn the wheel while you observe the coupling). There might not be enough room to keep the nut from turning with a normal spanner but a socket or box spanner might do the job.

Withdraw the bolt completely, otherwise you can't remove the disk. Remove the steering column lower shroud inside the car. Remove the top bolt of the steering column universal joint and loosen but don't remove the lower one. Pull back the rubber gaiter under the throttle pedal. Watch out for the stop light wires.

Pull the lower steering column together with the flexible coupling into the cabin. Take care not to use force if it's stuck, or you can damage the sensitive and expensive servo control valve. Once you have the coupling in your hands, just remove the connecting bolts, and replace the new coupling. Before tightening the nuts check that the steering wheel spoke points downwards when the wheels are in the straight-ahead position.

Lars GARLING