Citroen Hydraulics
Slim
Having now worked out how to use a computor, a friend of mine suggested
that I might want to have a look at these groups and share some
knowledge.
I have been working on Citroen hydraulic systems, from the Citroen DS
through to the Citroen Xantia. But not had a lot to do with the C5,
So, any questions and I will do my best to give you an honest answer to
help you from getting ripped off at the dealers.
Try me you might like it !!!!!!!!
Slim.
drd
Hi Slim,
Welcome! I'm sure your expertise and experience will be most welcome.
Perhaps I can be the first to pick your brains!
I have a 99 Xantia Estate Hdi - the back end sinks randomly when I come to a
stop - seems to do it when I take my foot off the brake - it sinks quite
gracefully and then pumps back up in 30s or so.
What's broke?
All teh best
Steve
Slim
spheres as rear brake accumulators, if you study the plumbing you will
find that the pressure goes from the rear height correcto to the rear
spheres via a junction, one pipe from this junction take fluid to the
rear brake feed in the brake valve. This means that when you operate
the brakes, the rear brakes will have a varied pressure depending on
what the rear suspension pressure is, IE if you put some paving slabs
in the boot, you will get more pressure in the rear suspension to help
lift the car, so therefore more pressure is sent to the rear brakes for
stopping power.
This can sometimes be a problem as when doing a long slow stop, then
sitting at the lights with your foot on the brakes, it will sap the
rear suspension of all the pressure reserve, thus making the car take a
dive at the back as soon as the brake is released, then the height
corrector tells the car its too low and the car comes back up. (good
news the heightn corrector is working fine).
You can demonstrate this yourself. Start the engine, put your foot on
the brakes then select high on thr lever, you will find that the front
will operate normal but the rear will be very reluctant to go up,
release the brakes and the rear of the car will jump up fast. Put your
foot back on the brakes and select low, the front will go down as
normal but the back will be held up by the rear brakes, release the
pedal and the rear will drop like a stone. This demonstrates the effect
of the rear brakes on the rear suspension.
As for the problem of dropping, this is normal but not as much as to
notice it too much, If the spheres have low pressure especialy the main
accumulator this can make the problem worse. The Xantia will typically
wear through a set of spheres every 3-4 years.
You could try pleiades at sawtry, I get hydraulic bits there
www.pleiades.uk.com
Hope this helps in some way.
Regards
Slim
drd
aha! I suspect its the accumulator then ... I recently bought a complete
set of 6 spheres (about £20 each from local factors...) and managed to
change all the wheel units "ok" but the front and rear centre spheres have
resisted my strongest persuasion without doing engineering on them!
It takes around 20s to pump up in the morning - also indicative of knackered
accumulator ?
many thanks
S
Slim
by about 2 x turns (never take it out) then using a good quality chain
wrench just undo it. then fit the new one but dont forget to fit the
new O ring seal, start the engine run for approx 2 mins, then tighten
the bleed screw.
The rear center sphere is the anti sink sphere, (this also doubles as a
rear brake accumulator) to change this, set the car in low with the
engine running, when settled in low stop the engine and open the 12 mm
bleed screw on the regulator, then using the chain wrench, (I use a
band wrench I have had for years) you need to undo it, BUT BE CAREFULL
this sphere is different to the others, it has a 4.5mm pipe (9mm
fitting) going directly into the rear of the sphere, hold a spanner on
the fitting and the 2 will come undone together.
Put it all back together not forgetting the seal on the 4.5mm pipe,
start the car, tighten the bleed screw then lift the suspension into
high and check the LHM level.
Regards,
Slim
DJ
"Slim" <marti...@tesco.net> schreef in bericht
news:1139607979.0...@f14g2000cwb.googlegroups.com...
Correction: the distance between frontwheels and backweehls depends on the
height of the car, there's is difference of a lot of centimeters. When you
have heighten the car and press the brake the wheels cannot move. When you
release the brake, the wheels can turn and the car drops!!!
The same occurs from the lowest position going high. Drop the car, press the
brake, set the car in highest position, wait for 20 seconds, release the
brake and the car will jump. I've enjoyed my children (and backriders) a lot
of times with this little trick.
Sorry hydraulic-specialist ;-) I'm just driving Citroëns with this kind of
suspension for only 40 years ;-)
DJ
Rob Beech
>
> aha! I suspect its the accumulator then ... I recently bought a complete
> set of 6 spheres (about £20 each from local factors...) and managed to
> change all the wheel units "ok" but the front and rear centre spheres have
> resisted my strongest persuasion without doing engineering on them!
> It takes around 20s to pump up in the morning - also indicative of
> knackered accumulator ?
>
> many thanks
> S
Just had mine done all round (96n xantia 1.9td estate) (friend of mine who
borrows the car regularly, was getting fed up of it taking about 30 seconds
to pump up in a morning so decided to do them for me for sphere cost only).
Can't believe the difference, 3 or 4 seconds and lthe lights gone. When in
the normal position the back end seems a little lower than the front, it
drives ok but could there be something not quite right?
Rob
Slim
on the rear suspension.
I am not a specialist, Just someone who has had quite a few dealings in
the hydraulics over the years.
You can please some of the people some of the time, but not all of the
people all of the time!!
Regards.
Slim
Slim
The only problem there could be the rear height corrector, This little
unit sits in the center at the back of the car, I have fitted quite a
few of these, and Pleiades tell me that they sell loads of them every
week, but in my humble experience, fitting some spheres will not upset
the height corrector.
Normal failure of the Xantia rear height corrector is failing to rise
at the back, this is usually caused by the height corrector siezing up
in its cradle and making the plastic link come off.
Your problem could be down to adjustment, but I would reccomend you
getting it over a pit or on a ramp to do this as it is dangerous to
crawl under a Citroen. Adjusting is easy when on a ramp, slacken the m7
bolt in the anti roll bar clamp and make sure that it can rotate freely
on the anti roll bar, then adjust the height corrector itself by
pushing the center of the height corrector towards the rear of the car
to go up or the front to go down. When the rear of the car is at the
correct height, tighten the anti roll bar clamp.
I cant remember what the height is, but if the front is fine, we
allways used to adjust it untill the sill was parralel with the ground.
Regards.
Slim.
DJ
Okay Slim, you're my man.
DJ
Rob Beech
> I cant remember what the height is, but if the front is fine, we
> allways used to adjust it untill the sill was parralel with the ground.
> Regards.
> Slim.
>
Cheers
I'll give that a try sunday when i finally get a couple of hours free.
For your information, it was like this before the sphere change aswell maybe
my initial post wasn't very clear. sounds likt this could sort it. it does
pump up. its not as if its right on the floor just doens't seem as high at
the back as at the front and also doesn't seem as high as the guy up the
roads (exactly the same barring the colour).
Rob
Adrian
saying :
> The problem here is that all hydraulic Citroens use the rear suspenion
> spheres as rear brake accumulators
It's not really that the rear spheres are used as "brake accumulators", in
the CX sense of the term.
It's more that the rear suspension is used as the pressure source for the
rear brakes, as the suspension pressure is higher when there's more load,
hence you get more rear brake. It's actually a very simple and clever way
of doing brake proportioning according to load.
Slim
You are of course correct is stating that it is very simple load
proportioning, much more reliable than the conventoinal type.
I think on my first post it reads as if this is a problem, I didnt
realy mean it that way, its just that on long slow gentle braking, then
sitting at the lights with your foot hard on the brake pedal, the
sudden drop is just something that happens! especially if the
accumulator pressure is low.
For some reason this seems worse when facing uphill.
Have a good weekend.
Slim.
Adrian
saying :
> For some reason this seems worse when facing uphill.
I've always laughed at the back end on ZXs/306s/Xsaras when you put the
handbrake on with the car facing uphill....
drd
many thanks Slim
I am slightly concerned at yourcasual use of "simply" and "just undo" ...
this car has done 130k miles and everything under the car is getting a bit
set in their ways now! I have broken a chain wrench and strap wrench
changing the four I have managed to shift, eventually!
There was top tip recently on wrapping a piece of studding round 'em and
boting to a piece of dexion or similar - think I'll try that for the
remaining two ...
all the best
Steve
Slim
Personally I use a Band wrench from Pleiades www.pleiades.uk.com this
tool I have used to remove hundreds of spheres, it was a good
investment, Chain wrenches are ok but it must be a goo un.
The spheres are not put on tight, its the electrolytic? corrosion
between the ally cylinder and the steel sphere, this mixed with a
little water and road salt, corrodes like hell.
To remove the rears.
Select high, I know it sounds daft but this will hold the cylinder
still. Then using whatever wrench you have, turn the shere a little, ie
6 o'clock to 4 o'clock. Thed select low (with engine running) when the
system has depressurised undo by hand.
If the cylinders still turn when on high, get a lond soft ended drift,
I use a brass drift, Place the drift on the end of the cylinder up to
the base of the sphere, give it a good hard clout with a heavy hammer.
this will crack off the corrosion and make your life much easier.
My casual use of simply undo comes with these instructions !!!!!!
Regards.
Slim
drd
Slim,
Where abouts are you? and do you do any private work?!
Steve (Shoreham-by-Sea, nr Brighton, Sussex)
Slim
Sorry but my days of crawling around under cars are gone. I live in
Cambridge, the Slim name comes from, when I used to visit Pleiades to
get my bits and bobs for Citroens, I used to stop and have a coffee and
chat with the big guy in the workshops, we got friendly over the years
and called each other Slim, (dont know why) we used to swop knowledge,
although I rather think that he has forgotten more than I could ever
know about the hydraulics.
I stopped working on cars a while back and the big thing that I miss is
not going on my trips to Sawtry to get my bits and chat with the other
Slim.
My best advice about working on cars is to get in and get your hands
dirty and get the job done!! Too much time can be wasted thinking
about the negatives.
Regards.
Slim
drd
Neomat
marti...@tesco.net says...
Hello Slim,
I have a Xantia ACTIVA ( i'm french so i doesn't know the international
name but think they didn't changed it ) and always searched the cause of
a so longgggg pressure run-high after starting engine ( about 1 min ) I
know that ACTIVA models have 9 spheres in total and normal xantia (
without hydractive or activa ) have only 6, stop me if i'm wrong :)
So ok there 3 more but from about 20-30 Sec to 1 minute there's a
difference :-X didn't know someone having the same model to verify.
For info the HP-pump and spheres were changed when i bought it last year
and it didn't changed anything.
My next car will probably the same model but with a so tinyyy V6 3.0
because the grip of the activa models is fabulous but the diesel engines
are really insufficient to ensure "usabillity" of the potential of this
car.
Regards
Neomat
Adrian
saying :
> I have a Xantia ACTIVA
> My next car will probably the same model but with a so tinyyy V6 3.0
> because the grip of the activa models is fabulous but the diesel engines
> are really insufficient to ensure "usabillity" of the potential of this
> car.
They made _diesel_ Activas? 1.9, 2.1, HDi?
Here in the UK, we only got the Activa with the 2.0 TurboCT petrol - but I
had heard that other countries got the v6.
Neomat
tooma...@gmail.com says...
ratio weight/power is too low with these engines if you want to "play" a
little with the incredible grip of this car
Only 1200 V6 activa ( 194 HP up to 240 with some modifications ) were
sold outside france so it's some kind of collection car :p
didn't know that only the 2.0TCT was sold in UK this engine is a monster
when you "debride" it ( sorry doesn't know the english word for removing
the performance limiters
Neomat
Slim
The Xantia Active uses a 6+2 hydraulic pump, the same as all Xantia's
with the anti sink system. This uses the 6 piston part of the hydraulic
pump for the power steering and the much smaller 2 pistons are left to
get the car up and do the braking. As you can see the suspension and
braking curcuits need to put a high demand on such a small pump, This
together with the fact that the Activa has 10 spheres is probabaly the
reason why you can hear the pump running for so long.
The spheres are as follows.
2 x front suspension spheres
1 x front suspension accumulator sphere
1 x front active ride sphere
1 x main accumulator sphere
2 x rear suspension spheres
1 x rear suspension accumulator sphere
1 x rear active ride sphere
1 x anti sink sphere
Have they all been changed? as when the system is out of pressure, it
will take longer to fill flat spheres with fluid than fully charged
ones. Even the newest of the Xantia's will certainly need a sphere
change by now, as typicaly a Xantia will get through it's spheres in
about 3 years.
I agree the Activa is one fantastic car to drive, but there is the
potential for a lot of trouble, this is why they did not sell very many
here in the UK.
Regards.
Slim.
Vincent Bellazzi
hydraulic circuit and the "big" part for the steering .
6 pistons for smooth steering caus there is no accumulator to keep constant
pressure if i remember.
But what a poor technological choice to keep the original pump, the activa
pressure demand is far beyond.
For example after a little ride on little ways if you stop for a 30 Second
break when you restart ( not the engine, the ride lol ) in the next 100
meters the pressure drop suddenly and recovers slowly (
conjoncteur-disjoncteur ? )
yes probably my spheres weren't all in good shape but i can't verify i don't
have anymore this car. it finished in a wall .... damn snow !! not a big
shock ( 15/20 kph ) but sufficient to break oil carter, the three radiator,
the front hydraulic device and the whole front shield.
Anyway thanks for your knowledge even if i have some difficulties on some
vocabulary (yes i'm french and not a grammar fan :p )
Neomat
"Slim" <marti...@tesco.net> a écrit dans le message de
news:1139856564.0...@g14g2000cwa.googlegroups.com...
Hazza
Hi I have a Citroen c5 estate and need the curly pipe and can not find one can
you help
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