Xantia CT with a few mods and Questions

[cam205gti]

Evening all


Had another thread going in the intro section so thought I would get another one going here as its in the correct section!

Ive been lucky to get into a very low mile 98 Black Xantia CT which was a one owner car. Basically never had anything other than oil changes in its life before I got it.

Ive replaced or regassed all spheres, fitted the diode mod black box, fitted a refurbished rear height corrector, new rear electrovalve and had the trailing arm bearings checked which were ok. Ive just had a more lively camshaft, an exhaust fitted and added a few more pounds of boost and is currently running nicely at 155 BHP at the wheels. She flies!

The car drives really well and Ive been enjoying learning about how the HA2 system works. I feel I have a fairly good grasp of how its supposed to work anyway!

Just had the LHM tank out and cleaned, along with the filters and a system flush. New fluid and an extensive brake line bleed.

The car was riding high in the rear most of the time around town and only lowered itself when at higher speeds before the fluid change. Around town it tends to raise up in the bum when your changing between gears and stays there which makes the ride at the rear terrible. I thought replacing all that I have would cure it. Not yet! Ever since the LHM tank was removed and cleaned and the new fluids the steering now has a 'notchy' feel to it almost like its coming in and out of assistance. ( belts are fine, was fine before and no slippage ). ALso when I dip the clutch now the low pressure alarm ever so slightly activates as the revs drop around 900 before settling at 950. Very annoying.

So, questions are.

Does it sound like there is a leak, or blockage to the supply of the pump after fiddling with the dreaded octo pipework from the tank? I do now have a small LHM leak coming from somewhere near there as its collecting from the lower part of the gearbox and dripping from there. Its not a rear main as the fluid is LHM. Could this be causing the steering issue?

And the rear raising up? A friend who is versed on Xantias thinks it probably needs the rear ride height adjusting a tiny amount. Does this sound right? What else can be causing it to raise up all the time? When its at higher speeds it tends to ride perfectly and at a level height. Could the dogbones be worn out or sloppy connecting to the ball? ( car has only travelled 70 000 kilometers and dry climate ) How would resetting the rear ride height cure it from raising up in between gears? It tends to lower itself at the traffic lights and then 5 seconds later it raises up again. Its really doing my head in and terribly frustrating after doing all this work.


If lowering/resetting the ride height does not work what else is there?


In hope

Cam!

[MikeT]

Well done changing the fluid and cleaning the tank/filters - it's a job well worth doing but equally disheartening to find there's still a seemingly big problem with the suspension. However, hopefully, it's a cheap and simple fix!

Firmly support the car on axle stands before venturing underneath, disconnect the rear height corrector dogbone, clean the height corrector mechanism, apply plenty of lube, work the mechanism back n forth then refit the dogbone.
I suspect that might sort out the rear height problem as I had exactly the same once; when braking, the rear would rise and stick high for some time (or, being a sinker, after cold starts, would drag it arse along the ground like a dog with worms). Classic sticky height corrector behaviour.

[Stickyfinger]

It is worth adding, that a can of WD40 (the only use for the horrid stuff) is good for using as a flushing lube/wash as it dissolves old grease and washes away the dirt. Dry it well afterwards and then lubricate with a good quality spray grease.

Only do this with the engine OFF

Agree with everything said by Mike above esp the Axle Stands.

[Mandrake]

The notchy steering after changing the LHM is probably an air leak on the supply hose. Check the main supply hose from the tank to the hydraulic pump very carefully for air leaks. If the hose is old it will have moulded itself to the spigot on the tank, if you don't get it back in exactly the same place it will have an air leak! Sometimes it's necessary to replace the hose because it has gone hard and won't seal again. Check all the other hoses at the top of the tank you have disturbed as well.

With the engine running remove the filler cap off the tank and shine a torch in there - if you see lots of bubbling or froth you definitely have an air leak that needs sorting out.

As for the rear height climbing as you accelerate hard through the gears - that is pretty normal for a high powered Xantia - my V6 does the same. This is because the front wheel drive torque causes the rear to squat down and the height corrector sees this as an error that needs correcting, so if you are accelerating for more than about 5 seconds continuously it will try to pump the back up a bit.

What is not normal is for it to stay there and be reluctant to come back down again. It should come back down to a normal height within about 10 seconds of easing off the acceleration.

Two possible causes for that - either the height is set a bit too high, or the height corrector assembly linkages are not moving freely in both directions. If rust is preventing it moving in the direction it should move when the car is too high it won't correct the height back down unless it is a long way out. Normally the height corrector should correct a height error as small as about +/- 15mm for the rear suspension or about +/- 10mm at the front.

So first check the height is actually set correctly. As a very rough rule of thumb the top of the rear tyre should be in line with the top middle of the wheel arch - it should NOT have a gap like the front wheel does. The precise height measurements can be found elsewhere on this forum. Generally I'd say that the height should be set within +/- 10mm of the correct figure - anything beyond this will affect the ride and handling significantly.

If that is correct then you may need to have a go at the height corrector assembly. You say you replaced the height corrector - did you just replace the height corrector itself (the drum with the pipes connected to it) or did you replace the entire height corrector assembly ?

Generally the height correctors themselves don't give any trouble, it's the linkage system with the two springs that causes 90% of the problems due to rust building up and inhibiting the free movement of the spring loaded arms. What condition is your linkage assembly in ?

Excessive play in the dogbone won't cause the issue - it would be popping off long before it had enough play to cause the symptoms you describe - and any play would cause it to be equally unresponsive to correcting the height upwards, it wouldn't just affect downwards corrections.

[xantia_v6]

The rear end of the car bobbing up and down with acceleration (especially on a car with manual transmission) is mostly controlled by the HA2 throttle sensor which causes the ECU to briefly switch into firm mode when the throttle is moved rapidly. This mechanism won't work if the throttle sensor is disconnected.

More likely you have been sold non-HA rear corner spheres which have much less damping causing the car to never really go into firm mode, thus the throttle mechanism becomes ineffective. I have experienced this and it is very annoying. With the correct spheres, and suspension in firm mode, the rear of the car should be very stiff, you should not be able to move the suspension much at all by hand.

Also check the mechanical stiffness of the rear suspension. with the suspension in soft mode (engine running), briefly lift the rear of the car by a few centimetres, and see what height it settles to, then briefly press down by a few centimetres and see if it returns to (more or less) the same height.

[Mandrake]

I have the correct spheres on my V6 and a working HA2 throttle sensor and if I accelerate from 0-60 flat out the height corrector will adjust the height back to normal during the acceleration resulting in the rear bobbing up like a cork to near maximum height when I take my foot off. That's normal behaviour.

What's not normal on Cam's car is it not coming back down again in about 5 seconds or 10 seconds tops if the height corrector linkage is a bit stiff.

Good idea to check the throttle sensor is working and the correct spheres are fitted as either of those will make it a lot worse, but don't labour under the illusion that the car will not do this when functioning correctly - it will. Even my less powerful HA2 2 litre petrol Xantia did this. The throttle sensor switching it to hard mode only stays in hard mode about 3 seconds which if you are accelerating for 6-7 seconds is only a mitigation, not a cure. The total amount of suspension travel is still the same over a period of acceleration exceeding 3 seconds, it just doesn't move as quickly and the initial movement is more heavily damped so you don't notice it nearly as much.

[cam205gti]

Wow. Thanks for all the responses. A wealth of knowledge.

The Spheres are the correct ones, Ive just crossed checked the numbers.

Ill investigate the HC mechanism and linkages and give them a good clean out. This looks like it may be the culprit.

The stiff steering could very well be from an air leak. Ill have a reall good poke around and see what I can come up with. Is there any other way air can get into the system other then being sucked through the supply line? I may mention that the steering is stiff/notchy in exactly the same positions as I turn. About 1/3 the way around 1 lock both left and right.

Where is the accelerator peddle sensor located and whats the best way to test it?


Thank you all once again for all the help. I would be lost trying to work it out. Now I know more about how it works it all makes sense!

Cam

[xantia_v6]

Notchy steering at fixed angles is usually due to the steering column U/J near the rack pinion needing lubrication.

The accelerator sensor for the suspension is at the top of the pedal.

Can you clarify whether the rear end dropping that you notice is immediate (during gear changes) or longer term during prolonged acceleration?

[cam205gti]

Thank you for the clarification

Ill have a look at the UJ and report back.

If Im travelling at 40mph in 4th and apply 50% throttle for 2-5 seconds as the torque makes the rear squat down. Ive not felt the car ever raise to a 'normal' height during acceleration. If I then change into 5th the rear with go up to what feels like full height and hang there for what feels like more than 10 seconds and is harsh and skittish over the road. The faster the car is travelling the less pronounced it is and the faster to return to normal height. In lower gears 1-3 pulling away from lights and general traffic driving its mostly raised in the rear. It will come down at the next light but can take upwards of 30 seconds or not at all until I take off again. It sometimes works faultlessly and is unbelievably soft and subtle. It only lasts for a few moments most of the time and then the rear is up and its all stiff again.

[ekjdm14]

Height corrector mechanism would be top of my list given the symptoms, but do check there's no air/gas getting into the system as that could also play silly buggers with the way the suspension works & can make the car feel less well damped and more "crashy" over surface imperfections.

Got any pics? Black is a great colour for a Xantia IMO (not biased at all haha)

[cam205gti]

Ill get some pictures when I pick it up. the paint is good, few small ding which Im having the dent guy remove. It then just needs a clay bar, polish and wax and should be good as new! THe engine bay is fairly dusty and Ive started to tidy that up. Was sitting in a windy carpark for years apparently.

Ill check the mechanism first thing. Ive also found a genuine supply hose for the pump so will fit that which should solve the air issue fingers crossed.

When its good its bloody good. Only it last for a few seconds!

[Hell Razor5543]

Something that can help are a few "Citrobics" sessions. When I had a Xantia I tried to do this monthly, including a brakes workout. What you do is;

Handbrake on. Raise the suspension to its' full height. Wait a minute, to allow everything to settle down. Holding down the brake pedal, lower the suspension to its' lowest level. The back end will remain up. Bracing yourself, release the brake pedal (the back up will drop rapidly). Holding down the brake pedal again raise the suspension to its' highest level. Brace yourself again, and release the brake pedal. Repeat a few times. Turn the steering from lock to lock a few times, waiting for 10 seconds at each lock.

Doing this should help keep things moving freely.

[cam205gti]

Small update

I managed to find a genuine Citroen suction hose that supplies the pump. I had a feeling that it may be sucking in air to the pump and being sent around the system. Changed that, primed the pump and still getting the same issues.

If the car is in high mode and then is transferred to low mode, the fluid that returns is full of tiny air bubbles. Is this normal?

The rear of the car is still holding a higher than usual height and the steering still stiff in certain locations. Can the universal joint cause the stiffness? It was totally fine before the tank clean out and once was put back together has stiffer than normal steering.

Another point to add.

Once I pull up and stop the car and get out the suspension takes about 5 or so seconds and returns to a 'normal' height. Which is about 2-3 inches from where it rides in the 'mind of its own' height. Ive tried lubricating the hight mechanism with no noticeable changes. If anything it now prefers to ride in the higher mode after a spray with WD40.

Is this all pointing to perhaps adjusting the rear ride height? What else can possibly make the rear of the car run higher than usual? Do any of the spheres have influence on the rear ride height? Do I potentially have a leaking sphere?

Im really not sure what to do from here. I hate driving it now as its not enjoyable and I feel its ruining the rear spheres as there always so stiff.

[MikeT]

Once I pull up and stop the car and get out the suspension takes about 5 or so seconds and returns to a 'normal' height. Which is about 2-3 inches from where it rides in the 'mind of its own' height. Ive tried lubricating the hight mechanism with no noticeable changes. If anything it now prefers to ride in the higher mode after a spray with WD40.

As already advised, WD40 is at best a short-term lubricate and only best used to shift and remove crud, after which liberal doses of long-lasting lubricant should be applied AND worked into the mechanisms through their full range of movement.

And again, don't forget Firmly support the car on axle stands before venturing underneath.

[cam205gti]

Yes I did get back in there with some spray grease. Made no difference. If anything it made it stay higher more often. Maybe its loosened it a little and now moves there easier?

Its a dry car and theres NO corrosion of any sort under there. It barely rains here and there is ZERO salt etc on our roads. The car has also only done 70k. I was under there yesterday ( with stands! ) and it all looks really good and clean.

What else can be causing it to run high? How can the height change through out the life of the car? Is there a reason or explanation of why they run high/stiff if an sphere is dud etc? There is such a massive difference in ride quality if its riding 2 inches higher than 'normal' it just astounds me. It almost like something is telling to raise up about 1 inch or so. As soon as I accelerate, even softly, it goes up and stay there.

Any reason the car when switched off lowers an inch or so to what looks like factory ride height? ( hence why I dont think the height needs adjusting )

Really annoying!