Nosediving Xantia

Xaccers · Unread post by **Xaccers** » 27 Apr 2009, 11:23

Driving Jenny for a few days recently, I noticed that when braking she tends to nose dive with the back going up quite a bit.
Now Cassy squats under braking, even when moving slowly.
Jenny has a much more floaty ride, whereas Cassy's is actually quite hard.
So which one is behaving properly, and what would cause the other not to?

Unread post by **Peter.N.** » 27 Apr 2009, 12:30

Its probably all down to the condition of the spheres, especially the centre ones (if they are hydractive) The centre sphere has far more effect on the total suspension movement that the outer ones.

Xaccers · Unread post by **Xaccers** » 27 Apr 2009, 12:51

Both are SX, and both have spheres that are about 6 months old.

KP · Unread post by KP » 27 Apr 2009, 13:58

How about the LHm in them??

Also how does she react to citroebics? is she as quick as cassy or does she creak a little? could be some rubber bush's causing it?

Unread post by **Peter.N.** » 27 Apr 2009, 14:11

Ah, right, I take it the SX isn't hydractive, it is on the XM. Any difference in ride between them has got to be down to either spheres or tyres, assuming that all the spheres are working correctly and are of the same type and condition, barring faults in the mechanicals, it must be down to the tyres, some are softer than others. Why the fronts behave differently - to be honest, I don't know.

MikeT · Unread post by **MikeT** » 27 Apr 2009, 14:39

Hi Xac,
I had a xantia that would pop it's rear up in the air when braking. It would drop if I released the brake but was a bit unnerving if you release at the point you accelerate again - it must have looked quite funny to other motorists was surely a pain to drive.

Additionally, that car would sometimes refuse to lift the rear from Low, whether manually selected or due to sinking when parked.

The guy who bought it off me told me it just needed the height corrector mechanisms cleaning as they'd got a bit sticky. Hopefully, that's your problem but I suspect you may have already carried out such maintenance?

Xaccers · Unread post by **Xaccers** » 27 Apr 2009, 15:03

Jenny responds fine to citrobics, the LHM is a nice green colour too.
Rear brake calipers are clean.
It's not really a problem, I'd just like to know why she reacts that way under enertia when Cassy (and I'm pretty sure my first Xantia as well) squat.

AndersDK · Unread post by **AndersDK** » 27 Apr 2009, 15:11

Both CX, BX and non-hydractive Xantia behaves like this if air is present in either or both the suspension and brakes system.

Try first lots of Citaerobics, then bleed the brakes all round.

If that does not settle the nose dive then it must be down to differences in sphere specs.

Unread post by **CitroJim** » 27 Apr 2009, 16:44

I'd agree Mike, the height correctors may well be the cause.

Going up and down OK on the lever does not necessarily mean they're in perfect health as the height lever works through a different set of linkages.

A good test is to make the front go down by say, sitting on the slam panel, getting off and whatching how the height corrects itself.

Unread post by **myglaren** » 27 Apr 2009, 17:09

Surely one of the points with hydraulic suspension that Citroen stress is that the cars don't squat on acceleration and don't dive on braking?

DickieG · Unread post by **DickieG** » 27 Apr 2009, 17:24

I agree with Anders on this, whenever one of my Xantia's lifts at the rear under braking I've found its always down to air trapped in the brake lines so a good brake bleed should sort it out.

Deanxm · Unread post by **Deanxm** » 27 Apr 2009, 18:00

Yep i would say air in the brakes too, if the front squats on it own the front spheres are underdamped/ incorrect or 'comfort' ones.

D

Unread post by **aerodynamica** » 27 Apr 2009, 19:17

I'll third it for Anders on air in the brakes for the squatting/ lift - I'm not certain why it sometimes causes lifting rear and other times squatting. My Xantia would lift at the rear braking and then pull down as the rear brakes then activated after the delay.

On the BX the rear would squat upon braking with trapped air due to the rear suspension pressure being much higher than the trapped air bubble pressure when they meet upon pressing open the brake valve and then compressing its volumne right down - manifested in the suspension height loss.

So, there's air in there.

Good news is that bleeding the rear brakes should cost nothing to DIY and if it cures it then YAY! free fix!