Rear anti-sink?

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Penguin
Posts: 252
Joined: 04 Apr 2008, 09:35
Location: UK
My Cars:

Post by Penguin »

This is very interesting stuff. Just thought I'd add my own problem. I recently bought a Xantia and everything worked fine. I had the lhm fluid changed and now mine sinks on start up if it has been left for a few hours. I believe it doesn't go down to its normal 'rest' state when I stop, but it certainly does when I start! It soon comes back up though. I wondered whether the guy that changed my fluid did something wrong?
User avatar
falling-out-with-my-car
Posts: 1928
Joined: 06 Apr 2008, 15:26
Location: Northamptonshire
My Cars: Citroen C5 Aircross 8 speed Automatic, Flair Model with far to many toys and nice comfy armchair like leather seats. ha ha Ive just had a conversation with the car. setting everything up verbally
x 24

Post by falling-out-with-my-car »

Penguin.

If youve ever owned a BX youll probably end up living with it.

I'm always critising my Father who starts his xantia VSX which sinks on start up he drives off straight away and because the pump is running faster the car recovers much quicker, in my Diesel SX I wait a moment for the car to balance out a bit, probably because I'm used to waiting for my old BX to rise.

Regards nigel.
Penguin
Posts: 252
Joined: 04 Apr 2008, 09:35
Location: UK
My Cars:

Post by Penguin »

Thanks FOWMC, this is only the second citroen I've owned and as the first was a ZX, its the first I've owned with proper Citroen suspension. I don't know if its psychological or not (I suspect it is), but if I stamp on the brake pedal it seems to speed up the raising of the suspension. I probably will learn to live with it unless there is a dead easy fix. Oh, BTW the guy that changed the fluid appears to have overfilled the tank as the float is jammed agains the top of the bulb when the suspension is at its highest setting! Time to buy a Turkey Baster I think.
User avatar
falling-out-with-my-car
Posts: 1928
Joined: 06 Apr 2008, 15:26
Location: Northamptonshire
My Cars: Citroen C5 Aircross 8 speed Automatic, Flair Model with far to many toys and nice comfy armchair like leather seats. ha ha Ive just had a conversation with the car. setting everything up verbally
x 24

Post by falling-out-with-my-car »

Penguin,

Don't waste your money syphon the dam fluid out with a clear tube or a piece of hose pipe, you will probably end up tasting LHM eventually anyway ARGHHHHHHH its disgusting. get the wife to do it LOL.

Regards Nigel.
User avatar
myglaren
Forum Admin Team
Posts: 25366
Joined: 02 Mar 2008, 13:30
Location: Washington
My Cars: Mazda 6
Ooops.
Previously:
2009 Honda Civic :(
C5, C5, Xantia, BX, GS, Visa.
R4, R11TXE, R14, R30TX
x 4888

Post by myglaren »

Fit a small pipe over an open bleed nipple, start the car and let the pump remove the excess fluid.
User avatar
falling-out-with-my-car
Posts: 1928
Joined: 06 Apr 2008, 15:26
Location: Northamptonshire
My Cars: Citroen C5 Aircross 8 speed Automatic, Flair Model with far to many toys and nice comfy armchair like leather seats. ha ha Ive just had a conversation with the car. setting everything up verbally
x 24

Post by falling-out-with-my-car »

Nope-its still cheaper to use a syphon...lol,

Its a good job your not in washington in the US because you would'nt be able to own an Xantia.
User avatar
myglaren
Forum Admin Team
Posts: 25366
Joined: 02 Mar 2008, 13:30
Location: Washington
My Cars: Mazda 6
Ooops.
Previously:
2009 Honda Civic :(
C5, C5, Xantia, BX, GS, Visa.
R4, R11TXE, R14, R30TX
x 4888

Post by myglaren »

True. Wouldn't want to anyway, although it looks as though my youngest is headed that way soon.
Penguin
Posts: 252
Joined: 04 Apr 2008, 09:35
Location: UK
My Cars:

Post by Penguin »

Damn! My woeful tale continues...

For those of you not following the various threads I have posted on here is the story so far.

Bought a 95 Xantia from Ebay, bit of a punt but the car looked reasonable and the suspension went up and down using the lever so all was well. THought I'd err on the side of caution and got someone to replace the LHM fluid, then my troubles began. As posted further up this thread the car stopped 'sitting down' when I switched the engine off, but would suddenly drop when started later. After reading a few responses I decided I wouldn't bother too much about it and just live with it. Then I got a phone call yesterday from a panicking wife who couldn't start the car because as soon as she put her foot on the clutch the car started rolling towards a gatepost. No brakes. Not unusual was pretty much the reply I got, so again I decided not to worry too much just remember to apply the handbrake 'properly'. This evening I went out in here for a quick jaunt, got home and decided to reverse the car up my, quite steep, drive thinking that if there was a problem in the morning for my wife it would be easier to handle facing forwards than backwards. "While I'm here" thinks I, " I may as well do some citrobics". Pull the lever back, car goes up, push the lever forward, car goes down. Excellent. Put the lever to normal front comes up quickly followed by.....nothing. Nada. Bugger all. The back just sat there looking at me, resolutely refusing to budge. Sat there a while, tried moving the lever back, front comes up further, still no response from the rear. Cycle it through a few more times, front works fine, but rear just doesn't want to play ball. Tried revving the engine, stamping on the brakes (Hey, I was deseperate, OK?) nothing doing. Finally I decided to very carefully drive the car out into the road and park it up so at least my wife will be able to use our other car tomorrow. Whilst parked on the road, which incidentally, is much flatter than my drive, the rear finall decided to wake up and rise to normal. At this point I swore at it and turned off the engine and locked up.

Now as anyone reading my other posts will be able to tell I am no mechanic, in fact I get quite bemused by mechanical things (I know, why did I buy a Citroen then I hear you scream) so I have no idea whats going on. I did hear a ticking from the front end about every 6 seconds, which I gather is not a great sign. Could this be part of my problem? Is it coincidence that I seem to be having problems since my fluid change, although I did only own the car for a week prior to that so it wasn't as if it had proven reliable for months.

Sorry for the meandering, ranting nature of this post but it has proved to be something of a cathartic experience.

Any advice (other than stick to Japanese in future)?

Cheers
MikeT
Posts: 4809
Joined: 11 Jun 2007, 16:17
Location: Christchurch, Dorset. UK
My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon
x 231

Post by MikeT »

I think you've just got one of those cars that hasn't been cared for as well as it could have been. It's similar to my unfit back... when I go to pick up something, I sometimes get stuck for a while before I can straighten up again. :roll: I know that frequent exercise will keep it more supple.

It sounds like the common problem of having corroded, sticky/stuck rear height corrector or something like that. If you can safely support the car on axle stands or ramps, take a look underneath for a link connected to a bar and the height corrector. Give it all a good clean and if it looks correct, cover it all with a protective layer of lubricant. For more info, browse or search previous threads. As I say, it's common enough.
admiral51
Donor 2023
Posts: 2625
Joined: 24 May 2007, 10:11
Location: poole dorset uk
Lexia Available: Yes
My Cars: C5 X7 2009 2.0 HDI VF7**************[VIN obfuscated, can be read by forum staff]
C4 2010 2.0 HDi Exclusive VF7**************[VIN obfuscated, can be read by forum staff]
x 378

Post by admiral51 »

It may pay to go back to the beginning so to speak and to depressurise the system and then repressurise it yourself that way you will be able to see that it done correctly (not doubting your mechanic)
if the bleed screw has not been tightened properly will this not let air into the system and prevent the acc sphere building up enough pressure to opperate the whole system?? (help :oops: )

as the system has a priority to drop power steering and suspension in favour of brakes it wouldnt take long to lose pressure for brakes as well

if the bleed screw had been fully removed and the bearing lost/not replaced what effect would this have on the Acc sphere would it not keep trying to repressurise every few seconds as what pressure it could generate it couldnt keep

sorry that most of this is just questions just thinking out loud

Colin
Penguin
Posts: 252
Joined: 04 Apr 2008, 09:35
Location: UK
My Cars:

Post by Penguin »

Thanks for that. The bleed screw is definitely done up, but I'm doubting whether it was ever undone TBH. When I looked at it yesterday it was covered in crud and there was no sign of a spanner having been near it.

Edit: Sorry for the stupid question but to depressurise the system do I simply turn the screw 1 turn and then do it back up or should I be doing something else as well?

Cheers.
User avatar
CitroJim
A very naughty boy
Posts: 49526
Joined: 30 Apr 2005, 23:33
Location: Paggers
My Cars: Bluebell the AX, Polly the C3 Picasso, Pix the Nissan Pixo, Propel the duathlon bike, TCR Pro the road bike and Fuji the TT bike...
x 6160
Contact:

Post by CitroJim »

Penguin wrote: I have no idea whats going on. I did hear a ticking from the front end about every 6 seconds, which I gather is not a great sign. Could this be part of my problem?
Yes, it is certainly not helping. A regulator tick every six seconds or so means your accumulator sphere is not in its first flush of youth and it requires replacing soonest. You should hear a tick no more often than 30s and when in good nick, the tick rate on an anti-sink car should be measurable in minutes. The accumulator, as it name suggests, stores hydraulic pressure and will acccount for no brakes when the engine is not running as there is no store of pressure available. A flat accumulator and hence short tick interval is not good for the hydraulic pump either. the tick you hear is the pressure regulator valve switching in and out to maintain constant hydraulic pressure. Its akin to a hydraulic thermostat.

If your accumulator is flat, there is a good chance all your other spheres are a bit sad as well, especially the rear corner spheres. I'd be tempted to do a wholesale replacement of all six spheres. You can tell the general health of the suspension spheres by doing a traditional bounce test with the height control in normal position with the engine running and bouncing each corner in turn. The suspension should be easy to push down and should rebound in a nicely damped way. If any corner is rock hard or bounces like a ball, the sphere for that corner is flat.

Reversing up a steep slope can confuse the height correctors someting rotten. You can sometimes confuse the height correctors when bringing the car off axle stands.
Jim

Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
aerodynamica
Donor 2023
Posts: 1299
Joined: 26 Dec 2007, 18:10
Location: Glasgow
Lexia Available: Yes
My Cars: 2008 C5 Exclusive Tourer
1993 Xantia 1.9 TD VSX Mk1 Sinker A.K.A Slugmobile 13'
'Old Katy'
previous convictions: totaling 52litres of LHM in one go:
1968 ID19B 'Old Polly' Stellar white
1993 Xantia 1.9 TD SX Mk1 Sinker Silver
1992 XM 2.0 SEi Turbo Manual Anthracite Grey
1982 CX 20 Pallas 'Old Goldy'
1993 XM 2.1 SD Auto Light blue
1993 Xantia 1.9 TD SX Mk1 Sinker light Blue
1982 BX 16 TRS 'Cyril' Vallelunga Red
1995 Xantia 1.9 D SX Auto Dark green
1977 CX 2400 Pallas C-Matic 'Aphrodite' Regatta Blue
1982 GSA Pallas SE Silver Pearl
1980 CX 2000 Reflex Vallelunga Red
1978 CX 2400 Pallas C-Matic 'Prometheus' Midnight blue
1984 BX 14E 'Cecil the slugmobile' Maroon
1987 Fiat Panda 'the mighty panda'
x 97

Post by aerodynamica »

if the bleed screw has not been tightened properly will this not let air into the system and prevent the acc sphere building up enough pressure to opperate the whole system?? (
It won't draw air in to the system but it will prevent the accumulator from charging. The pump is delivering LHM to the accumulator but the loosened bleed is letting it straight back out. When you've had the accumulator off or change of LHM, the bleed screw helps purge trapped air from the accumulator.

I find it strange that the foot brake went. Is it possible that the brake is working but with a terrifying delay? if so it's certainly trapped air in the circuit; that can be caused by replacing a component and not bleeding the brakes after it but since your's has not had any bits removed, it could be a leaking sphere babbling gas into the LHM - certainly not unheard of. :cry:
Graeme M
2008 C5 Exclusive Tourer 2.0 HDi
Penguin
Posts: 252
Joined: 04 Apr 2008, 09:35
Location: UK
My Cars:

Post by Penguin »

Aerodynamica, the foot brake wasn't working at all with the engine not running. I checked this later having run the car, and after 3 applications of the brake with the engine off I lost any effect from them. On start up the brakes are fine again. I think I will get the acc sphere replaced and see what difference that makes.

As a newcomer I'd just like to say that the people on this forum are incredibly helpful and friendly, and long may it continue.
aerodynamica
Donor 2023
Posts: 1299
Joined: 26 Dec 2007, 18:10
Location: Glasgow
Lexia Available: Yes
My Cars: 2008 C5 Exclusive Tourer
1993 Xantia 1.9 TD VSX Mk1 Sinker A.K.A Slugmobile 13'
'Old Katy'
previous convictions: totaling 52litres of LHM in one go:
1968 ID19B 'Old Polly' Stellar white
1993 Xantia 1.9 TD SX Mk1 Sinker Silver
1992 XM 2.0 SEi Turbo Manual Anthracite Grey
1982 CX 20 Pallas 'Old Goldy'
1993 XM 2.1 SD Auto Light blue
1993 Xantia 1.9 TD SX Mk1 Sinker light Blue
1982 BX 16 TRS 'Cyril' Vallelunga Red
1995 Xantia 1.9 D SX Auto Dark green
1977 CX 2400 Pallas C-Matic 'Aphrodite' Regatta Blue
1982 GSA Pallas SE Silver Pearl
1980 CX 2000 Reflex Vallelunga Red
1978 CX 2400 Pallas C-Matic 'Prometheus' Midnight blue
1984 BX 14E 'Cecil the slugmobile' Maroon
1987 Fiat Panda 'the mighty panda'
x 97

Post by aerodynamica »

OK Penguin, it's a fair cop the new sphere will help.
As a newcomer I'd just like to say that the people on this forum are incredibly helpful and friendly, and long may it continue.
yep! the way it should be - and we all know each others' pain :P
Graeme M
2008 C5 Exclusive Tourer 2.0 HDi
Post Reply