The suspension on my 93 XM was fine up till recently. Now when I start up the front doesn't rise. So I have to put whole system into full height - whole car rises as should do - then drop it to normal ride height. Then all is well and away we go with car riding normally. I suppose a vave is sticking, so is it a flush & replace fluid job that is probably required? Or maybe a swift blow with a hammer somewhere?

This is a job that could be explained easily with a picture, but I dont have one to hand. Must get round to it one day.

The height control, front and rear, is operated by a torque spring connected to the front or rear roll bars. In its simplest form, it is a rod of spring wire. One end is clamped to the roll bar, the other has an arm with a short link that connects to the height corrector valve. It position is such that the rotating motion of the roll bar, as the body rises and falls, is translated into a push-pull motion at the valve. The reason it is made of spring steel is that the corrector valve is internaly damped and cannot react immediatly to any input. This is to avoid the suspension trying to react to every bump in the road or even braking in to oscillation with the car bouncing up and down on the spot. Place a heavy load in the boot and the back sinks. The corrector can't move straight away, so the spring is wound up applying a force against the valve, which then eventualy opens after the damper lets it. The car raises until the load is removed from the spring allowing the valve to shut again, restoring the height. The basic ride height of the car is set by the position of these clamps on the rollbars alone.

So far so good, I hope. The complication arrises from the additional linkage to allow the ride height to be controlled by the driver. Attached to the valve end of the torque spring is an additional hair-pin loop of spring steel. One end is brazed to the the crank on the end of the torque spring. It then passes back towards the roll-bar clamp end of the torque spring, then loops around and passes back through a pivot hole in the crank, and then cranks up itself. The height controller lever from the cab straddles the end of this second spring, not touching it, in the normal ride position.

When the lever is set to high, or low, in the cab, the linkage pushes or pulls on this second loop of spring and pre-loads the main spring back or forth slightly. This 'fools' the height corrector in to thinking the car is in anything but the normal position, and the valve reacts to bring itself back to its neutral point.

Problems occur when the loop rusts and seizes in the hole. It must be free to move in the hole. If it sticks when the car settles overnight, when the car raises in the morning it reacts as if the height lever has been left in the low position. If the lever is moved to high, enough pressure can be put on the loop to get it to jump round to its normal position, and though driving may free it off for near normal operation, as soon as it stands it will surely stick again. The reverse can happen as well, if the car is set to higher then normal height it wont return to normal until the lever is pulled all the way back to the lowest position and then returned to normal.

The only sucessful way to restore it is to remove the whole assembly from the car, and vigourusly work the hair-pin spring in the hole usng plenty of WD40 to flush away the crud that will come out of the hole. Once it is free and clean, dry off the WD40 and pack all around the hole with a good waterproof chassis grease like Castrol CL3 that wont dry out. CL3 is a horrible sticky grease meant for exposed chassis points on boat trailors etc. Its like the grease version of chainsaw oil, if you put a blob between your fingers and separate them quickly the grease stings out into dozens of fine filaments.

Replace the link and reset the car ride height, this realy has to be done on a four post lift for safety reasons. It is also essential to enshure, when the height is set with the ride height lever in the normal position, that the end of the hairpin spring is central within the hole in the end of the ride height lever.

This fault is more usual on the rear where things tend to be a bit less oily and a lot more exposed to the elements. It could also be caused by dirt in the corrector valve, making the damping action slow to react, or even not react at all, but I would eliminate the control springs first as ths seems to be the most common cause of sticking, and is the cheapest option before replacing/ repairing the corrector valve.

Hi Alan,

Whilst a blockage cannot be ruled out at this stage there are easire aspects which can be checked and solved easier first.

The most common cause of this type of symptom is the 'spring' type linkage connecting the anti-roll bar to the height corrector. There is a piece of 6mm diameter mild steel rod with a 180 degree bend in the middle which connects the two together. The middle part of the rod is kept in place by a pivot which in turn has a connector arm ending in the ball and socket connector to the the height corrector. It is normal for the pivot part to become siezed and if not seized then very badly worn so that the pivot ends up being oval rather than circular.

The solution for the siezed option is straight forward. With the car on a ramp only (don't get under the car and play with the height correctors without a ramp otherwise it will kill you), disconnect the little plastic connector (looks like a pair of dumbells) between the lever assembly and the height corrector. The little ball and socket joints just plonk out. Exercise and grease the pivot point until it is free. Reassemble the plastic dumbell link accordingly.

If the pivot point is very badly worn then a replacement pivot point from a scrap car or Citroen is the only recourse I know of.

The anti-seizing needs to be considered first since its the most likely and the easiest to remedy.

Hope this helps.

Cheers

noz

Gentlemen! Thanks for an unbelievably rapid response! From what you both say it sounds as though it should be a reasonably straightforward job to clean up & free the ride linkage except for the need to access the car from below - I don't have any ramps and I can see that a four post lift would be preferable. So I think I will have a chat with my local Citroen independant garage armed with your comments/advice - it doesn't sound potentially expensive (or have I misread you?)

Thanks again,

Alan

Try spraying it with WD 40 first, may need several applications.

Peter.N.