Adjusting the rear height Xantia HDI estate

[isisalar]

High guys,
Finally got a replacement rear height corrector, courtesy of citroenxm, first class service, have had it fitted and the ride is now at least consistent but still feels a little too hard. After the old, bearing broken, cradle was lubricated the car would occasionally ride beautifully softly, not feeling any minor surface irregularities whatsoever, almost like driving over a rubber pillow. Other times it would be like a go cart and sometimes wallowing like a boat and hitting the bump stops on undulating roads.
I'm assuming that the cradle was sticking in various positions including correct, too high, and too low.
The setting of the height is the next job to get done and I would like to get it as close to the rubber pillow setting as possible which I'm also assuming was either just right or a little too high.
The car is settling at about 1/2 finger clearance, and whilst the ride is good it's still a bit jiggly over broken surfaces. When I managed to catch it on the pillow setting it was about 1 1/2 fingers. Would such a small height difference make such a difference to the ride, does it affect how much the center sphere comes into play?
I seem to recall that 2 fingers clearance between the tyre and the wheel arch is about right, would that apply to an estate? I've got to entrust this job to an indy and they seem reluctant to set it that high.
Lubricating the front corrector is also to be done soon as a precaution, if it is a bit sticky would it be best to get done first?
Since getting the bushes on the lower arms replaced, with genuine Citroen parts, and Lemforder droplinks the car is transformed and is a real pleasure to drive, I'd forgotten how nice it is to have a car that goes where it's pointed properly and doesn't rattle.
Interestingly the service history shows that the original bushes were changed at about 120,000 miles, and were replaced with £20 ones, obviously not genuine. These started to deteriorate by the time I bought it at 158,000 miles. Will be good to see how long the genuine ones last. For £36e@ it's a no brainer considering the labour cost of the job and the tracking.
Nearly there.
Cheers
Paul

[Stickyfinger]

to follow on from that...a big G

well the edit knackered my joke

[isisalar]

I'm not quite sure how I managed that, I think it was something to do with the enter button.Now edited.
Cheers
Paul

[citroenxm]

Safest and only way to adjust is to have a DECENT GOOD set of ramps. Put the car on lowest setting and lie under the car to MAKE SURE that it wont rest on you when you make the wrong adjustment...

Once your happy you are in the clear put the car back on normal setting height.

Under the car where the new cradle has been put on theres a Nylon Link Dog Bone, which goes to the anti roll bar clamp.

Arm yourself with a Ratchet and extension and 11mm socket. Have the car idleing. Lie under the car.

SLAKEN but DO NOT remove the 11mm nut on the CLAMP... then rotate the clamp on the anti roll bar SLIGHTLY!! DOes NOT need a lot of movement. Tighten the 11mm nut and wait to see what the car does. Depending which way you rotate, the car will either go up or down a bit... Im not 100% which direction to turn the clamp to adjust which way the car goes. If you turn and she lowers then obviosuly torn the clamp the other way. Dont have the clamp too loose you need some resistance when adjusting.. I use a screwdriver agaist the arm that attachs to the nylon link and against the clamp..

Small adjustments and eachtime tighten the clamp and do a bounce test to settle the setting.

[Hell Razor5543]

You need to allow for the probability the suspension will take a few seconds to react. Wait until it has settled before checking the height or making further adjustments.

If you can remove the spare wheel and its' cradle this will help a lot (lots more space).

As Paul said, you MUST make sure it is safe to be under the car. When I was at CitroJims' working on Gracies' front height adjustment the first tweak dropped her all the way down until her sump was touching my chest. THAT was unnerving, to say the least. Still, we got it right in the end.

[citroenxm]

You need to allow for the probability the suspension will take a few seconds to react. Wait until it has settled before checking the height or making further adjustments.

Tighten the 11mm nut and wait to see what the car does.

I thought I HAD already said that .. thanks for repeating..

[Hell Razor5543]

Sorry. I missed that bit.

[citronut]

if you are saying the ride quality is intermittent after fitting the replacement cradle, ut will not be height adjustment required,
as the adjuster on the anti roll bar can not be intermittent, unless the adjuster clamp is loose that is

[citroenxm]

following on from Malc's post, are the Spheres GSF spheres???

If so, remove them, throw them away and fit some from Citroen Service's (IHFS) spheres! They are always amazing, and soft too!!

[isisalar]

The ride is now perfectly consistent just a little bit more jiggly at the rear than it should be I think. The corner spheres are grey Citroën marked ones and are lovely and soft.All the other spheres are new from GSF within the last 8 months and seem to be fine..
I won't be doing this myself as I've no garage facilities.thanks for the safety warnings though.It's only a1/2hrs labour job thankfully so should be able to get it done fairly soon.
Should I be aiming for a 2 finger clearance for the optimum ride?
Cheers
Paul

[Mandrake]

Paul, if you're being picky about the ride quality and want to get the height spot on, don't bother with the fingers between the wheel and wheel arch rule of thumb - its only that, a rule of thumb.

Here is the exact method of calculating/measuring the height that allows for differences in tyre diameters etc:

http://homepages.igrin.co.nz/simon/imag ... ia_height/" onclick="window.open(this.href);return false;

Just as important as the height being correct is finding out whether it arrives at the same height when correcting both downwards and upwards, and whether it does so consistently over repeated attempts.

There is a certain amount of hysteresis in the height correction system to prevent it constantly over correcting, however sticky linkages can increase the hysteresis dramatically causing poor regulation of the ride height.

To measure the ride height precisely you need to measure where it stops after an upwards correction and a downwards correction, then take the half way point. So say that when it rises it stops at 120mm and when it falls it stops at 110mm, the actual ride height is 115mm with a hysteresis of +/-5 mm.

To get the upwards measurement I just lift that end of the car by the bumper until I start to feel it get heavier then let go - it will drop lower than normal then rise up to normal ride height - this is your upwards correction.

For the downwards measurement I do the opposite - I sit on the bump / slam panel until I feel it rising then get off - it will spring up too high then will settle back down - that is your downwards correction. Work out the half way point for your actual figure.

As to how much hysteresis there should be - a perfectly operating height corrector will have less than 10mm of hysteresis, that is no more than 10mm difference between the up and down correction figure. My previous Xantia was really good in this regard, the front was about 4 mm and the rear 10 mm.

20 mm would be acceptable and probably typical of a slightly sticky linkage and 30 mm or more would be unacceptable - the rear of my current Xantia is about 30 mm and you can definitely feel the change in ride quality as you drive as the car responds to different circumstances....and that's after the linkage has been thoroughly greased...

Properly sorting the rear height corrector linkage on mine is on my to-do list but fairly well down the list unfortunately...

[isisalar]

Thanks for that Simon. Once again you've given me a headache with information overload LOL.
Fortunately the corrector that came from citroenxm was a good clean one and was given a professional clean up and liberal greasing by the indy which fitted it, so working as well as it can.
With the best will in the world I don't think that for 1/2 hours labour the indy's going to be getting out the tape measures and the spirit levels but they are experts and took a lot of time and trouble when they did the job for me just after I got the car. They tend to favour a lowish setting so I'm going to have to insist on say 2 fingers, and pay to have it re adjusted if it's too soft. What I'm trying to achieve is the pillow type ride which happened occasionally with the duff corrector. Would I be right to say that the higher the setting the more the center sphere comes into play? That's what it felt like to me. A few mm one way or the other I'm not worried about it's the elusive hovercraft ride I'm after.
IIRC you posted up a similar guide to height setting which boiled it down to measuring the clearance from the floor to the bottom of the sill? 177mm springs to mind? I'm sure I saw somewhere on the forum also something about lining up the chrome bumper strips with the tyre somehow?
When it stops raining I'll go and check how much difference there is with the rising and falling settings.
Thanks again Simon
Cheers
Paul