Tail rising

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Philip Chidlow
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Tail rising

Post by Philip Chidlow » Fri Oct 31, 2014 9:35 am

I've had new spheres on the front, new accumulator sphere and the rears have been recharged. Kermit's done an LHM filter clean, the tank's all washed out and new LHM's been put in. But the car still exhibits odd behaviour: The tail rises under braking - It almost feels like the car's nose is diving... but it isn't; the back's actually rising up.

I think the old rear spheres are the next thing to consider replacing as a regas has softened them but maybe the return flow is too speedy (large hole) and I should consider, say GTI/16v rears spheres? What do you think?
• 1992 Citroen BX TZD Turbo Hurricane
• 2006 Xsara Picasso 1.6 16v

Tinkley
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Re: Tail rising

Post by Tinkley » Fri Oct 31, 2014 9:55 am

Give it a little time too. My 14 did this very slightly after new spheres all round and it settled down after a few days. There's an article somewhere in Technical (I think) about this which someone else may recall and point you to. As long as the rear arm bearings are OK and not nipped too tight ie correct shimming, that side should be OK. Rear height corrector? I had one fail and it was a bit odd with that part gone. After all the low nose diving, balancing of brake forces is one of the best technical features of the BX and superior to a lot of 'modern' offerings... :wink: ie quite a lot of new Focuses have rear drums etc etc.

'Tch 'tch you mean the so much better new cars actually aren't.....better at all!.

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Way2go
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Re: Tail rising

Post by Way2go » Fri Oct 31, 2014 2:26 pm

If you search the old postings the blame for this has in the past been attributed to the brake valve (doseur).
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Philip Chidlow
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Re: Tail rising

Post by Philip Chidlow » Fri Oct 31, 2014 2:53 pm

Yes, I'm just hoping it isn't lol!
• 1992 Citroen BX TZD Turbo Hurricane
• 2006 Xsara Picasso 1.6 16v

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Re: Tail rising

Post by Defender110 » Fri Oct 31, 2014 8:52 pm

Does it rise at he rear end after you have stopped with the brakes still applied? If so have you bled the rear brakes? as previously mentioned escaped gas from old spheres can get trapped in the brake lines, when you press apply the brakes the gas initially compresses and then expands again after stopping.
My TGD auto used to rise like this after the brakes applied and bleeding the rear brakes cured it.
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Re: Tail rising

Post by mds141 » Fri Oct 31, 2014 9:47 pm

After fitting new rear spheres and a change to hydraflush, the XM displayed some odd rear end behaviour. A good session of Citrobics seemed to cure it.
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Philip Chidlow
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Re: Tail rising

Post by Philip Chidlow » Sat Nov 01, 2014 12:48 am

It rises during braking then settles down, and after a second or two adjusts itself by rising a small amount.
• 1992 Citroen BX TZD Turbo Hurricane
• 2006 Xsara Picasso 1.6 16v

Kaapelimies
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Re: Tail rising

Post by Kaapelimies » Sat Nov 01, 2014 1:32 pm

Air in the rear brakes, bleeding cures the problem as said before.
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Philip Chidlow
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Re: Tail rising

Post by Philip Chidlow » Sat Nov 01, 2014 2:25 pm

I've got to replace the rear discs pads and callipers so will bleed them - hopefully that'll sort the problem. And the spheres are to be changed anyway... fingers crossed it gets solved.
• 1992 Citroen BX TZD Turbo Hurricane
• 2006 Xsara Picasso 1.6 16v