Xantia -project nearly finished, still have suspension issue.

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Dom_81
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Xantia -project nearly finished, still have suspension issue.

Post by Dom_81 » 06 Jul 2018, 16:50

Hello guys,

I've got a nice-looking 2001, non-hydractive Xantia HDI 109. Engine is great, and head gasket, timing belt, water pump and radiator all replaced (along with other work too).
Suspension SHOULD be great, as the car has new spheres, new height correctors, 1 new strut, has been flushed and runs with clean LHM.

The ride is a bit wibbly, like the car is not planted on the road fully and seems to affect all 4 corners, if I hit bumps the car seems to bounce on a diagonal plane sometimes. Sometimes, normally on very hot days, the car settles and the ride is 100% perfect (this is my 6th Xant so I know what it's supposed to be like). I found that putting the car in low, and depressurizing the system, seems to help temporarily. I've only done this a couple times recently and both times the car was spot on for a little while.

As the ride is good intermittently, I don't think it could be dodgy speheres and I replaced as a precaution anyway with no improvement - I'm thinking maybe there is air in the system, or an issue with the pressure regulator?, or maybe I need to do a more thorough flush?

Any ideas welcome, I've come this far so don't want to throw in the towel - I've got a second Xant waiting, but would be such a shame to give up on this one which I am getting close to doing!

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Re: Xantia -project nearly finished, still have suspension issue.

Post by xantia_v6 » 06 Jul 2018, 16:59

It sounds like you have air in the system, check for bubbles in the LHM tank. Make sure that the connections on the suction hose to the pump are really airtight.

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Hell Razor5543 » 06 Jul 2018, 17:01

I would check that the ride height is at the correct levels. If a Xantia is riding too high it can feel 'twitchy and unstable'. I do NOT know the correct ride heights, but a reasonable rule of thumb is that if you can get three or four fingers between the front wheel and the arch, and one or two fingers between the rear wheel and the arch the ride height is close to correct. However, I KNOW that somebody else who has more knowledge and experience then I will be able to give you the correct heights.

If you have to make any adjustments to the height make sure you are doing so in a way that will keep you safe. If a Xantia were to drop with somebody underneath it WILL kill them if there is insufficient space. Several years ago I was at a friends' place, and he was helping me to get the front ride height on my Xantia closer to correct. The front was up on ramps. I made a slight adjustment (but a bit too far), and she dropped. When she stopped moving her sump was touching my chest. If it were not for the ramps I would not be here typing this.

Something else that you might want to try is a Citrobics session (aerobics for Citroens). A full session can take 10 or 20 minutes. Ideally you want to do this on level ground, with the handbrake on (and the engine will need to be running throughout). After you perform a step wait for a minute or so (to allow the LHM to settle down, and any air circulated back to the reservoir to escape out). First, turn the steering from full lock to full lock (hold it at each full lock long enough to allow things to settle down). Do this five or ten times, which should eliminate any air from within the steering system. Return the steering to straight, and then raise the suspension to full height. Wait for a minute, then hold down the brake pedal (there will be resistance over time), and drop the suspension to the lowest setting. The front will drop, but the back will not (and will cause the rear brakes to have a workout, which is what you want). After a minute or so release the brake pedal (and hang on!; the back will drop quickly). Let things settle down, and then depress and hold the brake pedal again, and then raise the suspension to full height. Again, wait for a minute or so and then release the pedal (the back will attempt to launch itself!). Repeat this a few times, and it can help free up anything that is binding, and move any trapped air back to the reservoir. It is considered worthwhile performing a Citrobics session every month or so, to keep things moving smoothly.
Last edited by Hell Razor5543 on 06 Jul 2018, 17:25, edited 1 time in total.

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white exec
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Re: Xantia -project nearly finished, still have suspension issue.

Post by white exec » 06 Jul 2018, 17:24

Although a good soft ride should be available with the height lever set to Normal, it can get twitchy, as you say, when driving at Intermediate High. Just possible that the ride height of the car is too high, so - a quick test - try parking the height adjust lever a bit lower than Normal, without venturing too far towards Low. If this improves the ride, you'll know height needs looking at. You may need to tweak the lever's position while doing the test.

Air in fluid, as Mike says, always a culprit. Dip a sample with a small transparent container after driving the car; there should be no bubbles, even microscopic ones. Check also after doing some Citrobics.

Are you sure the spheres are good quality, and have the correct dampers and gas pressures?

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Dom_81 » 06 Jul 2018, 18:18

Thanks for these replies!

I forgot to say that the right height is as it should be, this is something which I'm very fussy about. Thanks Hellrazor - I now use ramps, put the car in high position, then use axle stands on the jacking points before lowering the car. Then when i put the car in high, the car conveniently lifts itself off the axle stands. I can imagine sump meeting with your chest must have been terrifying, i had imagined what it would be like to be pinned, still alive, with hot sump pressing down - cooking my heart whilst it still beats. I lowered the height of the rear of the car slightly so there is maybe 'half-a-finger-or-less gap', which should mean the ride at the back is harsher (but means the car corners really well) - and when the car is behaving, it is indeed a little harsh, but most of the time its just soft and a bit wibbly.

Before I go testing the spheres, I think I'll try the citrobics session as recommended, as it's something I've actually never done this before as hadn't heard this procedure described to fully and clearly and because it won't require spanners which is always nice. I just have a feeling there is air in the system, so I''ll put my bubble-detective hat on.

I will also check for air bubbles as suggested by looking in the reservoir, and taking a sample too. And will also check the pump and surrounding pipes/hoses.

Thanks again, I feel inspired by these leads, after previously having lost the will to live (sort of haha).

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Dom_81 » 06 Jul 2018, 18:21

I notice that the cap on the LHM reservoir has a black hose attached, which on my car is not attached to anything else... I'm assuming this is just an overflow pipe, or to allow air to escape as the level in the reservoir is fluctuating?

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Re: Xantia -project nearly finished, still have suspension issue.

Post by GiveMeABreak » 06 Jul 2018, 18:25

I second the air in the system issue - very symptomatic of a sporadically hard ride.
As for the hose - depends - there is an oil return pipe there - can you identify it below?:
Xantia II Res.PNG

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Hell Razor5543 » 06 Jul 2018, 18:29

Have you cleaned the two LHM filters (items 7 and 8 in Marcs' post)in the reservoir? I have seen these black with dirt, and cleaning them does make an improvement.

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Dom_81 » 06 Jul 2018, 19:42

So, would air cause a harsher ride? My can has the opposite problem.

I did a full round of citrobics exactly as instructed.... perfect ride was restored, but wore off after 10 mins. The contrast is easy to spot because when that distinctive reassuring harshness (because of me deliberating lowering it) at the rear goes away, it's very much unmistakable. This makes it much easier to tell when the car has gone wooly again. I did another round of citrobics and then came back along the same road, and it was like driving on a different road, but again wore off quickly.

Does that give any clues or indications?

I haven't done the bubble test but will do later or tomorrow.

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Re: Xantia -project nearly finished, still have suspension issue.

Post by white exec » 06 Jul 2018, 20:33

Xantia LHM tank, like earlier cars, is not pressurised, but open to the atmosphere via the filler cap and a shortish vent pipe. The pipe is not meant to connect to anywhere.

The ride on a non-Hydractive car should be soft, almost wallowy - and this is the normal state: really comfortable!
Harshness or nobbliness is not normal, and shouldn't be expected.

For air in fluid, first suspect is always the suction pipe that links the hydraulic pump to the reservoir. Hose clips (especially if stiff worm clips have been fitted) can distort the circular pipe, and allow air to be sucked in.

The two fine-mesh filters in the reservoir are there to trap large dirt particles and debris, but also have the function of breaking up (filtering out) air bubbles, created in return lines, etc., so that they are not recirculated into the system by the pump. Important that the two filters (one on input, the other on suction output) are snugly fitted, and do not have tears or holes.

Incidentally, one symptom of air in fluid is 'notchy' power steering, with maybe some less than smooth action at the steering wheel. Doesn't always show up, but if it does, a bit of a giveaway.

Your description suggests that the suspension is obviously capable of being soft and comfortable, so that points to the spheres being ok, otherwise this just wouldn't happen.

Lastly beware of over-inflating tyres, even by a couple of psi. Fluid suspension doesn't appreciate this, and it can cause crashiness. Michelins (even basic Energy's) were always good on these cars, as the system was designed around them.

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Re: Xantia -project nearly finished, still have suspension issue.

Post by aerodynamica » 06 Jul 2018, 22:27

Hi Dom, in addition to what Chris is saying another cause of bubbles in the LHM is bubbling being caused by the returned LHM from the various circuits and PAS dripping into the surface of the LHM in the tank. The returns emerge at the top of the LHM tank filter block and fall up to 2" to mix with the LHM in the tank and it causes bubbles on the inside of the mesh filter - some of which get through the filter and are immediatey picked up by the pump suction. I am not sure if it is a design fault but the solution (I think it might have been Mandrake originally) was to add pipe extensions from the 3 returns at the top of the LHM tank filter block that extend down to the bottom of the mesh filter to return the LHM to the tank under the surface. This is what got rid of the bubbles on my current Xantia (that now rides like a cloud) and previous Xantia and two XMs.

I think I have a thread on here somewhere that has photos of what to do to fix this (but might be on the XM forum - my memory is failing me!)

It truly does work - like Chris, I spent a lot of time a few years ago investigating why Xantias and XMs get bubbles in the LHM. As far as i can tell no other LHM Citroen suffers from this - my 4 CXs didn't despite the LHM tank filter block being of the eact same design as the XM/Xant save for it being white not black.

The ride on my Xantia was also improved by adding shims to the hydraulic pressure regulator cut in and cut out spring seats to restor the system pressure to factory levels. Also Xantia hydraulic pumps can draw in air at the join between the pulley flange and the pump body as I found out the hard way.

I also modify the Xantia height corrector actuating mechanism by either adding sealed bearings to a modified pivot bolt or by reaming out the holes for the pivot to take a larger diameter item that as less 'slop' in its action, the result is height correctors that react to getting in and out of the car in a way like the thing just left the factory... but then again, I'm a little obsessed. But well functioning height corrector linkages contribute hugely to the ride quality I found.

One other thing (sorry to ramble on!) I also had clear tubing fitted to my old XM 2.0i TurboCT with the bubbles issue and I found that it can take a lot of time to actually purge the bubbles from the system. Basically, with the clear tubing you could see the bubbles travelling along the tube to the pump. You could see them emerging back in the tank and you could see them in the pressure regulator return. I stopped the engine, released the system pressure via the 12mm bolt on the pressure reg, bubbles fizzed up in the tank ( so them must have been held in the accumulator) went away for 20 minutes till all the bubbles had risen to the surface of the tank, returned, ran the engine with the 12mm bolt still loosened and found bubbles reappeared from somewhere ( they were probably held in the pump or accumulator at the point where the pressure returned to atmosphere) and purged the bubbles a second time, After a wait re started, no bubbles, tughtened the 12mm bolt and waited for the pump to cut out - still no bubbles. Success! Turned the steering to lock and suddenly a surge of bubbles appeared in the clear tube to the pump !! arghh turning the steering had returned some stuck bubbles to the tank again and were picked up again by the pump!! this took a long time to purge.

Long story short: even if you've fixed the source of bubbles you can find that they have been held in the pump, PAS ram, accumulator return all to find their way back to the tank. My reccommendation is to run the engine for 5-10 second bursts and stop and wait for the bubbles to disperse, turn the steering and restart for 5-10sec again and wait for the bubbles to disperse again and so on for each component.

Worked for me!

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Post by Eddie Nuff » 07 Jul 2018, 10:06

Now that my sinker is back up and running it took two hours of Citrobics to purge the system - and that was bleeding through the brake nipples with all four corners on axle stands.

If all the air is out of the system my first point of call would be duff spheres - wether they are new or not.

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Dom_81 » 07 Jul 2018, 11:09

aerodynamica - yep you hit the nail on the head. I figured it out for myself this morning after confirming presence of bubbles, I checked the return hose from the pump which looked very snug... then looked at the cluster of hoses going to into the reservoir, the 3rd one from the front looked okay, but then just came off in my hand as wasn't secured at the non-reservior end. It does appear to be too short, so for now i have improvised but will aim to extend the pipe somehow so that i feel fully confident with it.

After a round of citrobics, and with a good drive about, the car is now as it should be. So thanks so much for all the good suggestions and helping me confirm my suspicion of air in the system.. I'll know to investigate that option first next time, instead of replacing good spheres etc.

@ white exec -i didn't know that was one function of the mesh (to remove bubbles), the system must be immaculate after all the hydraflushing though, and filters were cleaned. I opened up the rear height corrector valve as wondered if flushing had dredged up old gack and dropped it in the valve, but was squeaky clean inside. And yeah, I always put the higher-spec Michellins all round, as you say it makes all the difference, and I am careful to observe recommended tyre pressures too.

Thanks for all the help in fixing this! I can actually enjoy driving this car for once!! :)

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Re: Xantia -project nearly finished, still have suspension issue.

Post by Dom_81 » 07 Jul 2018, 11:15

@ aerodynamica - I like the idea of restoring the pressure regulator - I saw a video where a guy used a gauge to check the pressure. Also I saw that the brake control valve can be modded by taking the rubber thing out and replacing with a metal thing (shaped like a bullet) and this makes the brakes sharp. I'll keep an eye on things and try to monitor bubble levels, but at the moment the car seems to be going great, though may follow some of your suggestions just to help push remaining air out. cheers :)

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Re: Xantia -project nearly finished, still have suspension issue.

Post by white exec » 07 Jul 2018, 11:54

Dom,
Glad you got to the bottom of it.

" . . . the return hose from the pump . . . "
All the pipes on top of the LHM reservoir ('the octopus') are fluid return pipes, from various parts of the system - except one, which is the feed out (supply) to the LHM pump. This one pipe must be perfectly clipped and hosed, and without leaks, as it is under suction. Because of this, you will not see a fluid leak from it, but air can get drawn in. The usual problem is as described: distortion by unsuitable (non-round) hose clips at each end, and/or a bit of ageing of the rubber at the joints.

The slack return pipe you found could well have allowed air in, but probably not in large quantities. If leaky, a dribble of LHM might well show up there.

Well spotted, anyway. Hope the ride stays good.
___________

The reservoir filters
We did some experimentation a while ago, with shaken up and heavily aerated LHM poured into these filters, and watched what emerged as the fluid left the filter. Were surprised to see how effective the filters were are at breaking down/blocking bubbles, allowing almost completely de-aerated fluid to emerge. Heavily foamed LHM (large bubbles) was broken down completely.
The large filter catches the fluid from all the Return pipes, and allows it into the tank pool. The small filter surrounds the fluid pick-up pipe (pump supply), thus providing a 2nd stage of filtering.

You're right about Hydraurincage - it is extremely effective stuff.