Thankyou all for help on this forum having sorted out my Xantia Activa sinking problem (Plummeting suspension) ...New Anti Sink sphere on its way from AndySpares as I write.
SO...[;)]I thought I'd see if any of you knew why my car froze down the other day.
In several months of ownership I've had no probs with the suspension apart from the "dropping thing". The other day while driving to work I'd driven unavoidably through quite a lot of surface water here over Salisbury Plain. That night I parked my car as usual and it probably reached about minus 3 degrees. In the morning the back of the car dropped in its usual style as the lights went out then refused to rise at all.
I tried things like lifting then dropping the car, bouncing on it (used to work sometimes when I'd taken my old CX off a jack and it wouldn't come up) etc.
I had to drive the 2 miles or so to work so eventually I carried on, looking like some mexican lowrider with the front normal and the back down. Hoping all the time it would sort itself out. It didn't.
I concluded that it must be something to do with the water/cold and moved my car into the underground (marginally heated) car park. After leaving it for a couple of hours, I returned in my lunchbreak, switched it on and up it went immediately!!!
I wish I could say that it has been brilliant ever since but I'm convinced that the ride is uncomfortably firmer in the back than before.
Frozen Activa
Moderator: RichardW
Only logical explanation I see is some ice, maybe in combination with rust, between corrector and it's linkage, so it didn't open when rear end dropped. If something were wrong with the pressure supply, front of the car wouldn't rise, because 'working pressure' of front suspension is higher than of the rear, and also, rear anti-sink valve wouldn't open, causing mentioned drop.
About height correctors, I'll repeat one more time. AS LONG as ride height is correct, they don't affect the ride. During the drive, they are closed more than 99% of the time, opening only occasionally to top up the suspension, because of internal LHM leakage in hydraulic elements. Also, some LHM from rear suspension is used for rear brakes, but it' very low quantity (2-3 ml per 1 applying of brakes), unless dosieur valve is badly worn.
About height correctors, I'll repeat one more time. AS LONG as ride height is correct, they don't affect the ride. During the drive, they are closed more than 99% of the time, opening only occasionally to top up the suspension, because of internal LHM leakage in hydraulic elements. Also, some LHM from rear suspension is used for rear brakes, but it' very low quantity (2-3 ml per 1 applying of brakes), unless dosieur valve is badly worn.
That does sound familiar to me too. All my nonsense started after a tyre change... It all was fine before.
From what Alex says it would imply that things might be getting a bit stiff at the back... lack of oil or build up of rust and that moving it up to high , maybe it doesn't come back down to where it should be.
Is it on intermediate instead of normal height?
Do I remember that yours is an Activa as well?
Keron.
From what Alex says it would imply that things might be getting a bit stiff at the back... lack of oil or build up of rust and that moving it up to high , maybe it doesn't come back down to where it should be.
Is it on intermediate instead of normal height?
Do I remember that yours is an Activa as well?
Keron.
There could be a problem with height corrector's linkage, because of the rust or wearing. In Xantia, I think, one piece of linkage is made of plastics, which sometimes pops out. In that case, ride height won't be correct, so the ride will be rubish.
Height corrector can also be problematic, because of dirt getting into it's internal damping valve, or if one of the springs inside it breaks. But the symptom will always be incorrect ride height.
Correct ride height is in the middle between the lowest and the highest position, minus 5 mm on the front, and minus aprox 10 mm rear. So, check the ride height several times during a short journey, and if it happens to be incorrect, check the linkage.
Also, I think that it's possible to rupture the membrane in the sphere, raising the car to the highest position, if the spheres are old. In that position, spheres are subjected to maximum pressure, up to 170 bar, which is several times higher than rear suspension's working pressure. If the pressure in spheres was low, nitrogen inside them will be compressed to very small volume, causing high stress to membranes.
Try bouncing rear end on the left and right side (see the topic 'bouncing BX').
Height corrector can also be problematic, because of dirt getting into it's internal damping valve, or if one of the springs inside it breaks. But the symptom will always be incorrect ride height.
Correct ride height is in the middle between the lowest and the highest position, minus 5 mm on the front, and minus aprox 10 mm rear. So, check the ride height several times during a short journey, and if it happens to be incorrect, check the linkage.
Also, I think that it's possible to rupture the membrane in the sphere, raising the car to the highest position, if the spheres are old. In that position, spheres are subjected to maximum pressure, up to 170 bar, which is several times higher than rear suspension's working pressure. If the pressure in spheres was low, nitrogen inside them will be compressed to very small volume, causing high stress to membranes.
Try bouncing rear end on the left and right side (see the topic 'bouncing BX').
I had already tried that and each side bounces ok but seemingly a bit stiffer than before.
However, as it is an Activa and therfore has the Hydractive centre sphere, when it is jacked right up, that must fill completely too so the same argument cold be said of that one.
What would happen if the centre sphere popped? That would make it bounce both sides, but always be firmer than before, wouldn't it?
Also what happens to the Activa sphere (The one that ISN'T the extra accumulator) when the car is jacked up to the top? Does that fill completely too?
However, as it is an Activa and therfore has the Hydractive centre sphere, when it is jacked right up, that must fill completely too so the same argument cold be said of that one.
What would happen if the centre sphere popped? That would make it bounce both sides, but always be firmer than before, wouldn't it?
Also what happens to the Activa sphere (The one that ISN'T the extra accumulator) when the car is jacked up to the top? Does that fill completely too?
If the middle sphere is in good condition, you should notice significant difference between soft and hard mode, if you try bouncing the car by hands. If it's totally flat, there will be no difference at all - that axle will behave like in hard mode, no matter if solenoid valve in control block is energized by HA2 ECU or not.
The middle sphere on each axle is on the same 'working pressure' as other two spheres. At least it should be. If, due to some malfunction, it happens not to be, the car will exhibit sudden jumps or drops on switching to soft mode. I saw two such specimens in the last several months.
Setting height lever into different positions doesn't affect pressure in activa spheres. Pressure in front one equals to pressure in accumulator sphere. Pressure in rear one is controlled by the roll corrector. When going straight, it's about half of the pressure in front sphere. It changes in bends, so hydraulic rams on roll-bars extend or contract, keeping the car horizontal.
That's how I understand this.
The middle sphere on each axle is on the same 'working pressure' as other two spheres. At least it should be. If, due to some malfunction, it happens not to be, the car will exhibit sudden jumps or drops on switching to soft mode. I saw two such specimens in the last several months.
Setting height lever into different positions doesn't affect pressure in activa spheres. Pressure in front one equals to pressure in accumulator sphere. Pressure in rear one is controlled by the roll corrector. When going straight, it's about half of the pressure in front sphere. It changes in bends, so hydraulic rams on roll-bars extend or contract, keeping the car horizontal.
That's how I understand this.