new spheres; suspension still terrible

[jamieb]

In spite of replacing all spheres, the suspension on my 2.1 S1 is still bad: stiff, jerky, curiously dead. As far as I can tell, the electrovalve is working and anyway, it would not cause the utter crashiness of the system. It really is like driving with the suspension on High the whole time.

What I have noticed is that the ride seems better for the very brief moment while the car is pumping up if I set off before the car reaches ride height but I don't know if this is a red herring. I was thinking that possibly if the system was under higher pressure while pumping up, this would explain the very temporary softness.

The other factor worth mentioning is that the fluid was filthy when I took the car over. I've drained it and replaced with hydraflush - which immediately went pretty black. So far it's done about 2000 miles on the Hydraflush.

I was wondering 2 things:
Has anyone else experienced new spheres not making any difference and did you identify a cause?
Can dirty fluid knacker the suspension so completely? Is it question of more hydraflush for longer and waiting for a gradual improvement?

I've seen other threads where people were disapppointed by lack of improvement following a sphere change and the cause is usually linked to the electrovalves. However I've driven XM's stuck in sports and this is way beyond that.

Thanks for any input.

Jamie

[yaronlhm]

hello

say how is the condion of the strut mounting in your car?

did you do somthinng in them?


yaron

[jamieb]

the front strut tops are fine... are there other mountings to check?Where do I check them?

J

[Jan-hendrik]

QUOTE

It really is like driving with the suspension on High the whole time.

Is it by any chance? Is the normal ride height correctly adjusted?

QUOTE

What I have noticed is that the ride seems better for the very brief moment while the car is pumping up if I set off before the car reaches ride height but I don't know if this is a red herring. I was thinking that possibly if the system was under higher pressure while pumping up, this would explain the very temporary softness.

Your electro valve may be working fine, but it is no guarantee the hydraulic valves in the stiffness regulators are actually working. Sufficient hydraulic pressure is required for proper functioning. Only systematic troubleshooting using a pressure gauge can pinpoint the fault. The HP regulator can be adjusted to deliver more pressure. The internals of the stiffness regulators could be so gummed up that hydro flushing is not effective and only dismantling and cleaning will cure the problem.

Then the replacement spheres. Are they the correct parts? They could hardly all be of the wrong specs, but strange things have been reported of i.e. 'new' spheres that had sat on the shelf for years and lost their pressure.

Another thing that can cause a hard bounce at the front is a deformed strut. It takes just one to screw things up - excuse me. I have had the pleasure (!) with a BX. Probably had hit a pothole. Or just leave the front spheres on till totally depleted and it will wreak havoc on your suspension cylinders.

[jamieb]

Hi there

The height's fine and it goes up and down all right - a bit jerkily but no worse than other XM's with good suspension.

Two terms I don't know:

1) the stiffness regulator - I thought stiffness was controlled by the electovalve that decided whether or not fluid was allowed into the central sphere circuit. What's the stiffness regulator. I quite accept that it might be all gummed up.

2) the suspension cylinders. Where are they located?

As to the spheres: 4 came from AEP and two from GSF. It would very bad luck if they were all flat. I'm certain they're the right parts.

Thanks

Jamie

[demag]

I had similar problems on my 2.5 when I bought it. Yes I know, different set up, but it can take a long time to sort suspension issues. I doubt it will ever be as soft as your CX.

You say the lhm was filthy when you got the car. Have you checked the filters in the reservoir for cleanliness. Keep cleaning them to get rid of the crap.

Do you do Citerobics? Up and down on the suspension top to bottom as many times as you can. That moves the fluid around the system. If the system is gunged up it can take a long long time to get it clear. I ended up putting Bx spheres on the front of mine to try and soften it as I was worried about the strut tops. Did you have a new accumulator sphere fitted with the others? That can also have an effect. I found the back softened up fairly quickly but the front took much longer to sort.

If you do a search back a year or so in the Hydraulics section you will find some really good articles about this subject.

[jamieb]

Hi there

Yes, I;ve been trawling through past files and have come up with a list of things to do.

1) Be patient. Hydraflush works slowly.
2) Electrovalves - it makes all the right noises and the state of the suspension is far harsher than sports mode but it could be contributing
3) Droplinks and trailing arms
4) Front strut lubrication
5) Stiffness regulators - are these the valves that are controlled by the electrovalve?
6) Pressure - may be too low.

Any other suggestions?

Jamie

[Jan-hendrik]

The stiffness regulator is also called suspension control block. Your vehicle has 2 with 2 extra spheres. The regulators are controlled by one electro valve. The regulator contains an hydraulically controlled isolation valve which connects or isolates the sphere from the rest of the suspension system. The electro valve is driven by the suspension ECU and controls LHM under pressure to the isolation valve.
The isolation valve is a slide valve and when it has become severely gummed up it won't work the way it was intended to.

The suspension cylinders are the suspension struts.

[jamieb]

Thanks Jan-Hendrick. That's all clear now. Somehow, I had got the impression that there were two electro valves and they were the same as stiffness regulators. And I had never associated the suspension control block together with the stiffness regulators.

Hey on, on with the show.

Jamie

[Jan-hendrik]

Series 2 XM have 2 electro valves, attached to the regulators.

[Retron]

Hi all,

Just started to wonder if removing the HA CPU fuse will make the car softer? Another words: If I deactvate the failing HA CPU that keeps the suspension in Hard mode, the whole thing should becopme soft again right?

[robertmnorton]

Hi Retron,no,the H/A valve requires to be energised to operate soft mode.No cpu,no output.
robertm

[SilverSpider]

QUOTE (Jan-hendrik @ September 27, 2010 09:36 am) 

Series 2 XM have 2 electro valves, attached to the regulators.

Can someone show me a photo with series II regulator 2 electro valves?

[Jan-hendrik]

QUOTE (SilverSpider @ September 27, 2011 05:37 pm) 

Can someone show me a photo with series II regulator 2 electro valves?

The wording of my message was definitely fuzzy - I apologize. This might be better:
Series 2 XM have 2 electro valves, one (1) for each regulator.
Do you still need a photo

[SilverSpider]

QUOTE (Jan-hendrik @ September 28, 2011 04:40 am) 

The wording of my message was definitely fuzzy - I apologize. This might be better:
Series 2 XM have 2 electro valves, one (1) for each regulator.
Do you still need a photo

LoL! Nop. Now is clear to me Thank you!