Still harsh ride :-(

Post by **Peter.N.** » 06 May 2006, 15:31

Still sounds like mine! Hydropnumatic suspension is very poor at ironing out small bumps but very good at absorbing road undulations. It doesn't seem to react quickly enough. Tyres can make a big difference.

Richard Gallagher · Post by **Richard Gallagher** » 06 May 2006, 16:15

bernie wrote:Richard.
What spheres have you fitted to your HA2 Xantia's?

I've fitted standard (non HA2) Xantia TD/2.0 sphere's from GSF.

Mandrake · Post by **Mandrake** » 06 May 2006, 23:26

bernie wrote:
deian wrote:i doubt it's the tyres, we talking thunk thunk over medium bumps/potholes think drains that have sunk an inch and a half or so or something or small kerbs like heights again half an inch or so, over medium speeds 30 - 50 mph
Exactly like mine!!!???!!!

And mine....(most of the time)....

After the extensive work that I've done to diagnose this (which bernie can attest to....) I've come to the conclusion that this is due to air getting into the suspension - in my case due to a leaky pump. (I've replaced the inlet hose, and yet I'm still seeing plenty of bubles returning in the overflow line)

I also notice my pump has been getting more noisy over the last 6 months.

It was Anders who put me onto the idea of air bubbles in the oil side of the suspension causing ride harshness over 6 months ago but it has taken this amount of time and me eliminating everything else to finally start believing it....

On mine the symptom is the suspension crashing and banging over small sharp dips/bumps like manhole covers, and over the curb into drive ways etc as if there were serious loose joints in the suspension. (And yet there are not) The characteristics of the ride harshness also vary greatly from day to day as the amount of trapped air varies.

(If the air inlet rate is low the suspension will gradually self bleed, if it is high, the air will accumulate)

Some days, like yesterday, the ride is pretty good but still not 100%, other days its downright awful. The fact that it DOES have good days sometimes, tells me that its not a mechanical problem, but rather a hydraulic one.

When the harshness is particularly bad, I also start to notice a lack of damping - the car feels a bit floaty and unstable on undulations. On days when the ride is not harsh, the floatiness is not there.

I will be taking the pump out and stripping it down soon, but due to work and winter weather it will probably be at least 2 weeks until I can get a definitive answer as to whether the pump really is leaking and whether it solves my problem.

I don't agree with Peter's assertion that Hydropneumatic suspension (in general) is poor at ironing out small bumps - it depends highly on the model of the car, the type of spheres fitted, and the tyres.

One model which does suffer a bit from harshness over very small bumps (I'm probably going to get booed out of the forum for this) is the GS - the reason being that it has NO rubber bushings between the wheel and the body in the front suspension - the front suspension subchassis is bolted directly to the body metal to metal, and they ARE a bit rumbly on chip seal and harsh on very small bumps, but handle larger bumps well.

Not so for the CX, or Xantia, both of which have full rubber bushing isolation somewhere between the wheels and the body. (On the CX its between the suspension subchassis and body, on the Xantia its between the suspension arms/struts and the body)

Tyres can make a HUGE difference to the ride quality on chip seal and over very small imperfections. Tread depth is key here, a worn tread will ride more harshly, end of story.

Also type of tyre - a lot of people don't like Michelins but both me and my Dad have changed our Xantia's from other brand tyres to Michelin and the ride is much quieter and smoother on chip seal. (I put on new XM1's and Dad found some well priced second hand Pilot Primacys with about 50% tread, as he can't afford new tyres, and of the two the XM1's ride better, but probably only because they have new tread depth...)

So there are many factors involved but I don't believe that Hydropneumatic suspension is fundamentally poor over small bumps...

Regards,
Simon

deian · Post by **deian** » 06 May 2006, 23:43

yes simon, i have that crashy feeling over bumps too and i blatantly refuse to believe it should be this bad, i haven't seen much air in the tank yet although i'm sure there will be some if i looked at the right time.

when i hydraflush my car i will bleed the brakes extensively, i may not bother for now, i will live with the harshness, although i will take a wheel off and look at what the procedure is and so on. i always do trial runs before major jobs as it allows me to find the right components/bolts to open and the right tools for the job, and also to familiarise myself with any potential hassle i may get like seized nuts and so on and to work out the order of work, i use the bol as a guide then use my head to finish the job off.

out of curiosity, what does the hydraulic pump sound like... a warbling kind of clicking, humming, hissing? i have no idea! the engine drowns it out.

i understand the pump is repairable too, will you be attempting this, are there kits to be had? this has to be much cheaper than paying £160 for a new pump. I assume a new belt will be needed for this job, or can the old belt be used if it looks good enough? Does the belt actually need to come off or can it be slackened somewhere (i haven't looked at the belt procedures yet).

thanks

Mandrake · Post by **Mandrake** » 06 May 2006, 23:55

deian wrote:yes simon, i have that crashy feeling over bumps too and i blatantly refuse to believe it should be this bad, i haven't seen much air in the tank yet although i'm sure there will be some if i looked at the right time.

Unless its really bad you won't see it in the tank, as the return oil flows down inside one of the filters and only slowly difuses out into the main tank, by which time small amounts of air will have escaped to the atmosphere.

The way I monitored for it was to insert a loop of clear hose in the main overflow return line at the tank, then bubbles or lack of bubbles flowing through the pipe can be clearly seen. On mine there is abnormally large amounts of bubbles going through. (In theory there should be none)

See: http://homepages.igrin.co.nz/simon/imag ... irtest.jpg

By shining a torch through the side of the hose even the tiniest bubbles can be seen.

when i hydraflush my car i will bleed the brakes extensively, i may not bother for now, i will live with the harshness, although i will take a wheel off and look at what the procedure is and so on. i always do trial runs before major jobs as it allows me to find the right components/bolts to open and the right tools for the job, and also to familiarise myself with any potential hassle i may get like seized nuts and so on and to work out the order of work, i use the bol as a guide then use my head to finish the job off.

Well, bleeding the brakes may make the brakes work better, but it won't do anything for the ride...(well, not entirely true, it might affect the rear, since you'd be bleeding oil out of the rear suspension, but lowering the suspension does the same...)

out of curiosity, what does the hydraulic pump sound like... a warbling kind of clicking, humming, hissing? i have no idea! the engine drowns it out.

It's a kind of whiring noise, hard to explain. If you get someone to turn the steering wheel while you listen under the bonnet you'll usually hear it - it gets a lot noiser when the power steering load comes on.

Generally it shouldn't be audible over the noise of the engine when the pump is not under load (not lifting the car or turning the steering) but in the last month or so mine is. A slightly noisy pump doesn't necessarily mean a problem, it's just I notice mine has got noisier.

i understand the pump is repairable too, will you be attempting this, are there kits to be had? this has to be much cheaper than paying £160 for a new pump. I assume a new belt will be needed for this job, or can the old belt be used if it looks good enough? Does the belt actually need to come off or can it be slackened somewhere (i haven't looked at the belt procedures yet).

thanks

I don't know about any kits, (probably not available in NZ anyway) but yes I will be attempting to repair it.

Without knowing what is wrong with it yet (if anything!) its hard to say what it might need, but my guess is it probably needs at least a shaft oil seal, and maybe new bearings for the shaft. (If the pulley end bearing is badly worn for example it would cause the belt tension to pull the shaft out of line and damage the seal or at the very least cause it to leak)

Both should be available off the shelf from engineering suppliers. I believe there is also a seal where the two halves of the housing join together.

But I guess I'll just have to wait and see what I find inside!

(I'll be taking pictures...)

As for the Auxillary belt, I see no reason to replace it if its ok. Remember the same belt also drives the alternator and air conditioning...and I don't think there is anything wrong with the belt on mine... (no slipping or squealing etc)

The belt tensioner depends on the engine, some are spring loaded auto tensioners, some are manual screw adjustment types. The tensioner is only accessable through the right hand wheel arch where you take off the wheel and remove the plastic cover.

Regards,
Simon

Stempy · Post by **Stempy** » 07 May 2006, 09:11

Well I finally got around to fitting those diodes and it made a significant difference in the performance of the suspension on my Xantia. So much so that I was almost taken by surprise by the amount of increased body roll in slow corners, and it's much nicer to drive over speed humps too.

I fitted the diodes inside the suspension ecu, a fairly easy job and keeps things neat.

deian · Post by **deian** » 07 May 2006, 10:05

nice idea there simon, i like it, don't forget the screw driver tucked in the back. do u not prop the bonnet hook in it's hole, or did u raise it up to take the picture?

your car is the same colour as mine?

i know the whirring your on about, there is no whirring from mine unless i move the power sterring, so the pump is ok, must check the pipes like you did, i guess it's a short term solution, as the pipes need to be special, i'd love clear pipes all round, any ideas there?

it'd be cool if u take pictures of the the pump disassembles, as many as you can, then you could shove them in the forum archives for reference, have you thought of getting a 'www.flickr.com' picture account? well worth it, and it's free.

take care and let us know my friend.

Mandrake · Post by **Mandrake** » 07 May 2006, 10:36

Stempy wrote:Well I finally got around to fitting those diodes and it made a significant difference in the performance of the suspension on my Xantia. So much so that I was almost taken by surprise by the amount of increased body roll in slow corners, and it's much nicer to drive over speed humps too.

I fitted the diodes inside the suspension ecu, a fairly easy job and keeps things neat.

Good on ya...

I've still got the electrovalve fitted at the front that has the faulty internal diode and it has been relying on the external diode in the ECU box for the last few weeks and as far as I can tell it's been switching reliably the whole time.

I will get around to swapping it over eventually though as a precaution since I do have a spare coil sleeve with a good diode in it sitting around...(it does no harm to have a good internal diode AND an external diode at the same time)

Regards,
Simon

Mandrake · Post by **Mandrake** » 07 May 2006, 10:43

deian wrote:nice idea there simon, i like it, don't forget the screw driver tucked in the back. do u not prop the bonnet hook in it's hole, or did u raise it up to take the picture?

Nothing escapes you does it...

Yes it wasn't until a few days after I took that picture and emailed it to someone that I noticed the screwdriver sitting in the background of the picture. (Luckily I'd noticed the screwdriver and removed it before closing the bonnet)

Yes the bonnet was right up at its vertical extreme for the picture.... very handy for working on things at the rear of the engine bay especially on the right. It's a shame they don't have a second bonnet stay loop to hold it there rather than needing to tie the bonnet back...

your car is the same colour as mine?

Don't know... what colour is yours

mine is dark metalic blue, but I don't have a good external picture of it at the moment.

i know the whirring your on about, there is no whirring from mine unless i move the power sterring, so the pump is ok, must check the pipes like you did, i guess it's a short term solution, as the pipes need to be special, i'd love clear pipes all round, any ideas there?

Well I wouldn't leave mine there permanently... its only a means to solve the bubbling problem. Not sure exactly what grade of pipe it is, its something Dad got, supposedly its petrol/oil safe, although it does soften and become somewhat pliable with engine heat. It's been on there about 3 weeks now, and will probably remain until I solve the problem.

it'd be cool if u take pictures of the the pump disassembles, as many as you can, then you could shove them in the forum archives for reference,

Yeah, I've started taking pictures of the work like that I do on my car, I should have started a bit sooner, as I forgot to take pictures of things like the time I stripped the height correctors down...(although Doublechevron has put up some good pictures of that now on his site) or the time I removed and stripped the Hydractive blocks. (although i did take pictures of the insides of the electrovalves...)

have you thought of getting a 'www.flickr.com' picture account? well worth it, and it's free.

Nah, but I have webspace of my own (where the images are linked from) and one of these days I'll have to write a Citroen page that has all the pictures I've taken included

Regards,
Simon

Post by **Peter.N.** » 07 May 2006, 11:56

When the pump is worn it will make a sort of 'clackety' noise when its actualy pumping. I fitted a new one to mine this year, it still makes the noise to to a much lesser degree. It has improved the suspension rise time, but not the ride.

deian · Post by **deian** » 07 May 2006, 13:18

this is my car simon... http://www.flickr.com/photos/deiz92/ notice the little boxed dotted around the pictures with notes, this is why i suggest flickr, it rocks!

Mandrake · Post by **Mandrake** » 07 May 2006, 20:39

Peter.N. wrote:When the pump is worn it will make a sort of 'clackety' noise when its actualy pumping. I fitted a new one to mine this year, it still makes the noise to to a much lesser degree. It has improved the suspension rise time, but not the ride.

Yeah, the 'clackety' noise is probably just wear in the pistons/bores and although it would cause increased noise under load and possibly reduced pumping capacity due to leakback around the pistons, it wouldn't cause air suction problems, which has to be a seal leak somewhere on the input side...

Looking at a cutaway diagram of the earlier single output Xantia pump which is similar (unfortunately I don't have one of the two output pump) there are only two seals that could be the culprit - there is one on the pulley shaft, and a large square section seal sealing the end cap on the pulley end. Both are on the suction side.

All the other seals are on the pressure output side and thus couldn't cause a suction leak. My money is on the shaft seal. Oh and by the way it looks like the shaft bearings are actually bushes not ball bearing races ?

Guess I won't be replacing those after all....

Regards,
Simon

Mandrake · Post by **Mandrake** » 07 May 2006, 20:40

deian wrote:this is my car simon... http://www.flickr.com/photos/deiz92/ notice the little boxed dotted around the pictures with notes, this is why i suggest flickr, it rocks!

Yeah, I've seen flickr before.

Yes your car is the same colour as mine...

Regards,
Simon