Xantia - Rear Height Corrector - strange behaviour

[ecohouse1]

Since I got my Xantia TD estate last year - I have lubed and cleaned up (in situ) the rearH/C

I replaced all the spheres last month and the (filthy) LHM

Doing Citrobics - can raises to full no problem - when I then select normal ride height, front comes down gently to normal height and stops. Rear continues down, below normal ride height then sits lower (but not as low as service/minimum height!).

I plonk myself on the rear deck and car raises up to normal ride height. (even with engine off using accumulator pressure)

Car loaded up with kids and boot full of stuff - sits nicely at normal ride height. We all get out - car lifts up as weight gone, then sinks below normal ride height again! - I sit in the car - up it comes to normal ride height.

I am reluctant to fiddle with the height corrector settings as the ride height is normal when driving around.

Is this a sticky mechanism? I keep soaking it in spray grease and release oil!

Cheers

Alan

[Mandrake]

Yep, it will still be a sticky linkage. I had the same problem on my current Xantia, although the error in height was smaller than you describe.

When it corrects in the downwards direction it goes too low, in the upwards direction too high. the top horizontally moving lever arm with the spring wrapped inside it which links to the height corrector drum itself will not be moving freely and smoothly - rust causes the moving part of the arm to drag on the stationary part of the bracket, leading to overshooting in height correction and a lack of sensitivity to small height errors.

Although you might not realise it it will be causing inconsistent ride height (and thus ride quality) whilst driving too - as the rear height corrector is always busy correcting for acceleration induced squat it won't be coming back to the same height each time after accelerating from a standstill.

I just put as much grease as I could in and around the top slide arm / spring (injection with a grease gun would be ideal but I don't have one) and after a few days of driving to exercise the linkage the error in up and down height correction went from pretty bad (60mm+) down to about 20mm, still not ideal but acceptable.

Unfortunately this mechanism wasn't designed with salty roads in mind, and is a bit "over engineered" compared to the very simple linkages used in older citroens which essentially connected the roll bar clamp directly to the height corrector through a length of torsion bar with a small lever at the end, instead of using a complicated pivoting arm with spring - in the older torsion bar approach there were no sliding surfaces to rust together so they never gave any trouble...

If the rust is too bad and doesn't respond to repeated attempts to lubricate and exercise it, the only recourse may be a replacement height corrector spring/bracket assembly. (The height corrector itself should be fine)

[ecohouse1]

Thanks Mandrake, I hear a "ping" noise as it comes down - like something sticking then releasing quickly! Possibly the spring you refer to.

I remember never having this hassle with BX's - I remember the small bent torsion bar and many happy hours adjusting the collar and finding a mm movemnet on it resulted a large difference in height!

Funny you mentioned the ride quality as I feel that the rear end is a bit firm compared to the front even with new spheres and doesn't have as much up & down "float" as the front.

[Mandrake]

Yes if something is making a ping noise the mechanism is dragging or sticking. It might also be worth checking that the manual override adjustment is correct - with the car at normal ride height and the height control lever at normal there should be equal free-play in the manual override part of the mechanism. (bottom vertically facing spring arm)

If the ride quality at the rear feels a bit firm with no float and the spheres (and hydractive system) are ok that suggests the ride height is too low during most of the time you're driving leading to the bottom progressive snubber being gently touched by the suspension arm.

Generally rear ride height too low will cause a firm ride lacking in magic carpet feel, while too high will (up to a point) cause a ride that is too floaty and a bit overactive/lively on cornering...