Will a C5 lift its wheels off the ground?

bencowell · Unread post by **bencowell** » 01 May 2005, 23:37

If you put a C5 on axle stands/bricks etc and lowered the suspension height, would it lift the wheel off the ground?

wheeler · Unread post by **wheeler** » 01 May 2005, 23:41

No,you need the weight of the car for it to lower.

macaroni · Unread post by **macaroni** » 02 May 2005, 00:27

Is this the same for all hydro Cits?

Robin · Unread post by **Robin** » 02 May 2005, 00:40

My Series 2 XM and 98 Xantia will both lift their wheels on command. Saves jacking. I just raise to max height place jack under and lower the car. The wheel nearest the jack lifts clear. Have also done this with the front on stands and lowered the back. The front lifts as the rear lowers. Have not tried it with all four wheels though. I suppose it is possible that it could be the geometry of the body lowering and lifting the supported wheel/s. Robin.

AndersDK · Unread post by **AndersDK** » 02 May 2005, 01:01

You're right Robin -
But if you jack up the car then you can NOT make the wheels lift UP (i.e. up into the wheelarch) by the hydraulics.
The hydraulics suspension can only counter-act the weight on wheels - it can not work like robotics.
This is because the suspension cylinders are single-chamber rams - not double acting (i.e. like a servo steering ram).

ActivaV6uk · Unread post by **ActivaV6uk** » 02 May 2005, 02:42

Sorry Anders. Your wrong, as the fluid leaks back to the system the wheels will come up whether there on the floor or not and this is true of the BX (its happened to every bx I’ve eve stripped (that’s over 15 cars) and my Xantia Activa I’m currently working on its not instant but give it a few hours and they will come up...
Andy

AndersDK · Unread post by **AndersDK** » 02 May 2005, 02:55

Andy I think there is some misunderstanding here ?
Me - ?
or you - ?
As I read the above text - the car is jacked up no weight on wheels. The wheels hanging down by their own weight.
In this situation the wheels can not move up by the hydraulics. Period.
Maybe I'm way out in the woods ?

ActivaV6uk · Unread post by **ActivaV6uk** » 02 May 2005, 03:11

it suprised me too but ive found that over time the wheels retract back into the archest the fastese are the rear wheels. when stripping i tend to put 4 pairs of tires under the car so its not on any of the wheels, it became a problem for me what i waited a day to take the back wheels off a 16v and found that the wheels had retracted into the arches and even thouhg i could undo the wheel bolts I could not get the wheels past the arches any more... the only ansever I could come up with was that the fluid must return to the tank and in gdoing so creates a vacume. I found this very puzling but after car 3 I got use to it, now I just tend to see how long it takes...
Andy

AndersDK · Unread post by **AndersDK** » 02 May 2005, 03:26

Now you got me out in the woods - way out [xx(]
Ever seen a rear cylinder on a BX ? The cylinder rod has a ball link firmly attached to the radius arm - by the famous lock pin.
The other end of the rod just mates into a plastic guide inside the piston - not attached here.
Meaning the cylinder can NEVER pull up the wheels.
What you are referring to is the wellknown cause of a minor heart attack when you want to fit the rear wheels of a jacked up hydro Citroen : strangely now you can not get those d... wheels on [V]
- although they came off no pains [:o)]
This problem is caused by the rubber stop inside the rear frame tube. which is compressed when height is set to highest - by the system pressure.
No system pressure - you can NOT by hand compress the rubber stop - and then there is not enough clearance to get the wheels on.
Solution : start engine, ensure height is set to max, and wait for system pressure to press down the rear arms that extra inch you need.
Except now happens the second minor heart attack : those d... rear arms are still hanging there loose no pressure - what is wrong ?
As the rear arms are already near the lowest point, the HC is mostly closed in this situation - not allowing the rear suspension to be pressurised.
As we know from another recent thread : lift up the rear arms a while until the HC opens - and voila Harry Potter came by to help you.

FDV · Unread post by **FDV** » 02 May 2005, 03:46

Sorry Andy, gotta agree with Anders on this one! Its impossible for them to retract isn't it? The system would have to work in reverse surely?
I know mines been jacked up for a week or more on LOW setting and the hubs are still dangling.
The only reason it works on something like the BX when you want to change a wheel is basically that when you put two axle stands under the front points for example, and lower the height, the back will drop right down and the car uses the stands as a pivot kinda like a seesaw effect. Its just enough clearance to remove the wheels and it works both ways on the 16v with std wheel and tyre sizes. Same would apply if you positioned them under the rear points.
I've seen DS promo videos showing it doing it side to side, ie stands under the left causing the right to drop right down when lowered which results in the left hand sides wheels raising into the arches. I'm fairly sure here that this is because the anti roll bars (assuming the DS has something along these lines) are forcing one side to copy the other?
If it doesn't have them then Andy could be right with the DS at least. [8D]

NiSk · Unread post by **NiSk** » 02 May 2005, 04:21

Anders - what you are forgetting is the anti-roll bar. If you raise a BX/XM/XANT to highest postion, stick a jack under the body to support one of the wheels and then lower the car again, the wheel closest to the jack will ift up clear of the ground - this is due to the force exerted by the anti-roll bar that is connected to the wheel opposite!
I know - I have tried it on my old BX, both current XMs and a freinds Xant.
However, as just pointed out -it doesn't help much if its a rear wheel you want to get off! there just isn't enough room to get it past the bodywork - (but don't we love that famous Citroën styling?).
//NiSk

AndersDK · Unread post by **AndersDK** » 02 May 2005, 04:50

I'm certainly not forgetting the ARB NiSk [8D]
- now you're referring to the sitation when you jack up ONE side of the car - and then lower the suspension.
Surprise - surprise - lifted off wheel is pulled up by pure magic [8)]
Now back to origin :
Put a C5 on axle stands etc, lower the suspension, the wheels are just dangling there pressed down by their own weight.
- as does any hydropneumatic Citroen.

Unread post by **Peter.N.** » 02 May 2005, 14:17

I'm with Anders on this one

ActivaV6uk · Unread post by **ActivaV6uk** » 02 May 2005, 15:37

Don't understand why its happend to all the cars I've worked on then, i know it doesnt sound right it didnt make any sence to me either, next time i have a car do it i will take pictures and we will see what people can come up with.
Andy

vanny · Unread post by **vanny** » 02 May 2005, 16:07

Is it not just caused by a vacuum when the pressure is removed?
I always change wheels on the BX by using the suspension and ARB to lift the wheels up on one side, but i've also but the car on four stands and done it and the wheels do retract even though there is no weight on them. It's initailly quite slow and they dont go all the way up into the body but they do lift, i usually then stick a jack under the wheel and force the rest of the fluid out.