Citroen XM Forum

I spoke too soon. The tailgate gas lifter ball joint was seized solidly and broke/had already broken off the strut casing
After freeing off the ball joint I thought it might weld onto the gas strut...it nearly did, but then the casing melted sufficiently to release the gas...
New gas strut required...

As mentioned the gas strut ball joint snapped off due to being seized Welding it back on was going well until the third tack melted the pressure container and the gas leaked out.

P# for gas struts is:
96026964 80
The originals were Stabila Lift O Mat 890146, which are no longer available, but other ones are, though they are not identical in either end fittings, or gas pressure, which originally gives a force of 683N. Having searched I settled on a pair of Quinton Hazel QTS128381, which are physically identical and have a force of 680N.
Fitting is pretty straight-forward, raise and prop the tailgate, unclip the spring clip and pull/work the pin out of the ball socket, then pull the socket off the ball joint on the car body/tailgate. I had to replace the ball on the very seized side where the strut snapped off, as the ball was worn and the pin bent. Clean and grease the balls then having removed the spring clip on the new strut, clip the socket onto the ball, then refit the spring clip.

Even the side that was not seized had a fair amount of rust in the ball joint socket, which made it difficult to separate from the ball.
The tailgate now self lifts once lifted from the fully closed position, instead of requiring manual lifting to raise it, as the new struts are providing more force than the old ones were.

While in the tailgate area I looked into why the central locking wasn't reliably unlocking and found corroded electrical contacts on the lock unit.
Cleaned and greased and it is now functioning. Observations on the Estate:

The boot is vast, I have to climb in to reach items against the seat back. The covered side containers are useful for small item storage, such as a bottle of lhm, some diesel additive, a Hi-viz vest, etc.
I've just checked the capacities and payload info for 2.1td:
Saloon: Boot Volume seat up: 460L, seat folded: 1460L, car payload: 530Kg.
Estate: Boot volume seat up, below parcel shelf: 720L, seat folded: 1960L, Car payload: 630kg.

When unloaded, the ride quality isn't as good as an Xm saloon, due to the rear suspension and spheres being set for increased payload, along with stiffer anti-roll bars.
In all other ways this car is performing well in daily use, even in cold temperatures. The engine and drivetrain first appeared very lethargic, but after 100 miles, both are now operating with a bit more verve.

I've noticed longer cranking before starting time and sometimes lumpy running after start. Originally I thought a glow plug might have failed, but then suspected an air leak into the fuel system. On twisting the hoses I found the semi-rigid hose from the metal pipe across the manifold, to the fuel heater was loose at the pipe end, so have replaced the click-clip with a worm drive one, sufficiently tightened to stop the hose rotating when twisted. Time will tell if tis is the fix.

The centre panel in the tailgate had come unbonded so I removed the number plate lamps and the centre panel, cleaned the mating edges and have re-bonded it with structural adhesive. Unsurprisingly, the sunroof is jammed closed and lets water in after rain, or washing the car. The motor moves, but the mechanism is very seized, even banging on the glass won't move it.
To gain access to the motor you remove the interior lamp console, to access the sunroof guides you can remove the glazed section.

Unclip the inner plastic trim round the front edge of the sliding roof guide, then the four screws holding the metal slider to the front edge of glass cassette. Which will reveal three torx screws on each side guide. Remove these and the glass will lift out. Be careful as the steel screws install into brass inserts and do seize. Use penetrating oil and ensure you don't spin the insert in the plastic guide. When re-installing I use copper-slip to stop seizure. Even after using penetrating oil and plenty of tapping I couldn't unseize the moving guides and cables, but was able to rod out the front drains using some net curtain wire, which will hopefully stop water over-flowing into the car.
I tested all four drains by pouring water into the roof cassette and seeing where it drained from.

The hydraulics pump belt had started chirping, then squealing, so as a short term measure I tightened it by adjusting the pump, but the belt was worn as noted by it retreating down the pulley sheaves.
When a belt moves into the pulley sheaves, due to being worn smaller it has a reduced surface area for grip, but also due to the effective pulley diameter reducing, it is required to transfer more torque, so will wear faster.

I fitted a new Pix Spz X-set 1087 belt.
Loosen the pulley pivot and clamp bolts, push the pump as low as possible and work the old belt off. To install the new belt you may need to gently lever it onto the pulley, or place it and briefly crank the engine to wind it onto the pulley.
To tension, pry the pump upwards while tightening the clamp, then pivot bolts.

A longer belt will fit more readily, but you may run out of tensioning adjustment.

Old belt running inside pulley sheaves.

The car has been leaving a spot of Lhm when parked. On checking the base of the regulator was wet.

I cleaned up the oil using paper wipe and brake cleaner, then ran the engine while observing.

I have some regulator O rings, but didn't immediately have time for stripping it off the car. Fortunately the leakage point became apparent as the pressure relief bolt O ring. You can just see the oil glistening in this image.
There is some wetness at the base, but I think this is just residual oil.
I unscrewed the relief bolt and recovered the ball bearing; i tried to catch it in a container, but it missed and fell on the floor. I could see the old O ring was obviously worn out.
Citroen state the O ring is 6 * 1.9mm, so a new 6 * 2mm O ring was fitted, I stuck the ball to the end of the bolt with grease and re-installed it, leaving it loose for a minute with the engine running, then tightening. After some running all was dry.

In due course I'll replace the other two O rings on the regulator. See post on regulator overhauling. viewtopic.php?f=19&t=2665&p=131612#p131612

I've noticed the engine is taking longer to fire when cold and is lumpy for a few seconds after it does.
The most common reasons are, either a glow-plug has failed, or there is air in the fuel system, so firstly I wanted to check the glow-plugs are functioning.
Anyone with a Bosch pump 2.1Td knows that extracting No's 3&4 glow-plug are a real challenge, due to the fuel pump being in the way.
I removed the intake upper manifold and intercooler pipe, as as these glow-plugs are fed from a common supply, removed the nuts bolting the cable to No's 1, 2, 3 glow-plug.
When removing the M5 nuts, ensure you have a magnetic pickup tool positioned to catch the nut as it unscrews off the glow-plug.

I did perform a resistance check on all four plugs and they all read correct at 1.6 Ohm. I also checked continuity using a high wattage test lamp wired to Batt + and each glow-plug terminal.
After that I tested the relay was functioning and delivering sufficient power for the glow-plugs. It was so I reconnected the plugs and feed cable, then re-installed the manifold and intercooler pipe.

Ii then checked the fuel pipe connections for tightness, by attempting to twist each one on it's spigot. The one onto the fuel pump did rotate, so I tightened that clamp.
I'm not yet convinced this issue is fixed, so will monitor.

I also fitted new battery clamps as the original lead ones were worn, with the negative clamp compressing fully before it stopped being able to twist on the battery terminal.

I found the easiest way to remove the old clamps was to cut the side of the crimp with some side cutters split the cut with a chisel, then wiggle and pull the cables out.

The cold starting delay continued so I looked further for possible air leaks into the fuel system.

I checked the air bleed and water drain on the filter unit for tightness and was able to tighten the drain 1/6th of a turn. I decided to bypass the fuel heater mounted on the side of the cylinder head, as these are a known leakage point and not necessary since in cold months we use Winter diesel in the Uk, thus the risk of waxing in the filter is much reduced.
I believe the air leakage issue is the O ring that seals the heater unit wears out, but replacing it is a bit of a task as the complete unit has to be removed from the side of the cylinder head, which also means draining and refilling the cooling system.

I cut the hoses and inserted a 10mm copper pipe.

I also changed the clip at the pipe to hose joint on over the intake manifold, adding some rubber sheet to ensure the clip was very tight, as these are semi-rigid hoses. The cold starting delay now appears to be sorted, with instant starting, no chugging, stalling, or smoke.

Since putting the car on the road I've been unhappy with the ride quality, which was very bumpy and choppy. Initially I was sure the system was stuck in hard mode, but was too busy to put time into it. Over period of weeks it did start to improve and I could tell it was engaging soft mode, but it was still stiffer than it should be...almost as if it was half in soft mode, half in hard mode.
The ride was very brittle and jittery.

I have previously checked for power and Gnd to the Ecu and the electrovalve showing the correct resistance, measured at the loom in the engine bay.
I decided to check the sphere pressures, as when recommissioning the car I put a new pair of IFHS spheres on the front corners and iirc, a new accumulator, the rest I re-gassed back to specification.
As the rear felt stiffer than the front I started there: I ran the car onto ramps, lowered the suspension, but due to the front being so low and the engine bay on this car being very full, couldn't open the pressure bleed on the regulator, so after switching off the engine pumped the brake pedal about 100 times and also moved the height selector several times to call for pressure, then set it back to low.

I expected the rear centre sphere to come off easily after a few thumps with a lump hammer, but it was still tight on, so I used my sphere tool. After loosening it it started to drip fluid and once the pressure was depleted, I unscrewed the sphere.

The rear corner spheres came off easily by gripping and turning with my left hand, while giving it a clout with the hammer.

I tested the part numbers and pressures which were all correct.
This is a Hydractive-1 estate: H1 is known to be stiffer than H2 setup and being an estate it has different rear spheres and pressures to a saloon, to cope with additional loading and the rear ram pistons having 20% larger area.

I referred to the Citroen Private Car books for specifications, which appear to be different to ones from aftermarket suppliers.
For the Citroen information see viewtopic.php?f=13&t=11023

. As the spheres, not the Hydractive system, provide the ride quality, I checked the damper central orifices were correctly sized.
Larger spheres, with more gas volume/pressure will give a softer spring rate, larger damper orifices will give a softer, less jittery ride, but at the expense of greater roll when cornering.
Through the life of the Xm, Citroen increased gas volume and damper orifice size to give a more compliant ride, which is why H2 equipped Xm have a smoother ride than H1 ones. In addition Series 2 Xm also weigh more.

The electronics simply switches between soft and hard mode and shouldn't directly control ride quality.

I used measured drill bits to check the centre drillings and found them to be on the tight side of their specification, so drilled them. I actually drilled them 0.02mm oversize.
The specification for these particular spheres is:
Front 0.6mm
Rear is 0.7mm
I refitted the rear spheres and ran the front of the car onto ramps, lowered the car, opened the regulator bleed and switched off. This should have fully depressurised the hydraulics, including the centre spheres.
Upon unscrewing the front centre sphere I was surprised how much residual pressure there was still locking it on. Again I unscrewed it enough to allow it to drain then removed it.
This made me think the hydraulic shuttle valve must have closed (hard mode) before the main circuit pressure had depleted after unscrewing the pressure relief. As the engine was still running it should have stayed open due to the electrovalve still being powered.

After checking pressure, re-drilling and fitting the spheres I decided to check the electrovalve connection. The electrovalve is mounted behind the front subframe on H1 cars.

There was noticeable corrosion on the connector pins and sockets, which I cleaned with contact cleaner, wire brushed with a mini brass brush, fitted/took apart several times, greased to stop further corrosion and refitted.
The electovalve power feeds are particularly important as they utilise a reduced voltage created by using PWM to reduce the +12v feed. Any connection issues are very likely to cause spurious behaviour, either sticking in hard mode, or a quasi state somewhere between soft/hard modes.
Testing the car revealed the ride to be noticeably better and definitely in soft mode unless switched to hard mode.
If I want the ride softer, or less damped, I can adjust the gas pressures, or centre drillings accordingly.

That reads like a flow diagram to diagnose hydractive issues! Nice work Will, and again a thread I hope I'll be able to find when I need it...

Citroen suspension and Hydractive are pretty simple systems and generally easy to diagnose. The spheres create the ride quality, Hydractive switches between the two modes.
One test is to monitor the electrovalve, or force the suspension into soft mode, while monitoring ride quality.

Since performing this repair, I have noticed when sitting in the car without the engine running, after opening and closing a door the electrovalve has a definite rhythmic hum for 30s, heard inside the car.
This is a normal sound caused by the Pwm reduced voltage causing the solenoid core to vibrate and I can't remember noticing it before performing the connector cleaning, though I did hear the electrovalve clunk at power off. It stands to reason the better the electrical connection the louder the hum.

From previous testing on another car I have some oscilloscope traces of the 30 seconds of electrovalve power taken with the ignition off, door opened, then closed again.
During the power on phase the 1Khz Pwm signal appears almost random, but throughout the on cycle it changes...which when sitting in the car you can hear if listening closely. This causes the electrovalve to hum different sounds during the cycle.

The engine had been sucking air into the fuel pipes again causing delayed start and a puff of smoke, so I changed the hose between the steel pipe across the manifold and the filter head.
The old semi-rigid pipe had become so hard it couldn't seal when fitting over the swage on the metal pipe, even with clips done up very tight.

As a safeguard, I added some non-setting gasket sealant onto the spigots, before fitting the new hose. I can see those hoses being difficult to remove in future as a result, but was fed-up it kept leaking air.

The new hose wall is thinner, so I added rubber as cushion under the clips. I'll perhaps cut a new piece sometime, as it's not very neat...