Xantia Spheres

[wizzymichael]

hi all,

what is the physical difference between an accumulator sphere and the suspension spheres. i notice my activa turbo has 7 spheres in total. i notice that the accumulator sphere(front of engine) and the drivers front sphere are hot after a run but the rest are barely warm. whilst driving it has no problems,but when stationary it slightly rocks from left to right on the suspension.any ideas or suggestions. have service history showing spheres regassed a few years back,has done nearly 93k.will be changing them in the near future as knowing what a difference it made when i did them on my last xantia.

also has any body fitted a dump valve on one of these?

[andmcit]

hi all,

what is the physical difference between an accumulator sphere and the suspension spheres. i notice my activa turbo has 7 spheres in total. i notice that the accumulator sphere(front of engine) and the drivers front sphere are hot after a run but the rest are barely warm. whilst driving it has no problems,but when stationary it slightly rocks from left to right on the suspension.any ideas or suggestions. have service history showing spheres regassed a few years back,has done nearly 93k.will be changing them in the near future as knowing what a difference it made when i did them on my last xantia.

also has any body fitted a dump valve on one of these?

 

Hi Michael

 

I've only recently got my head around my Activa a bit more and have found a massive wealth of info on Xantia/Activas here:

 

http://www.frenchcarforum.co.uk

http://z7.invisionfree.com/ActivaNet/index.php?act=idx

 

The Activanet guys have experience with dump valves/performance mods etc.

 

There are 10 spheres on an Activa.

 

2x corner spheres front

1x centre hydractive front accumulator

1x Activa SC-CAR front accumulator

1x main system regulator accumulator

 

2x corner spheres rear

1x centre hydractive rear accumulator

1x Activa SC-CAR rear accumulator

1x Anti sink

 

To look at with a casual glance all the spheres will look the same - ie round and green!! ;-)

However, the area of gas volume can vary between various parts of the Activa and other Citroens from 400 to 500 and IIRC 600 for Ds and Cx Safari models. Then there's the gas pressure inside the sphere which can vary from 40bar to 70bar so a lot of variables come into play here too. Combine this with the accumulator sphere being VERY different from the conventional corner spheres in that there is no jet or orifice in the threaded end of the sphere compared to the tiny 1.3mm (or thereabouts) opening on the corner. The accumulator has a big open bore on it's threaded end the diameter of the thread and an inset jet of a far greater diameter - approx 8mm.

 

I'd expect the spheres will heat up, the fluid is being pumped around the hydraulic system via the pump bolted onto the engine so I don't think the heat will cause any issues - it's an oil after all! Try using Hydraflush fluid cleansing solution that's sold in 5l to keep the system in good order before using fresh LHM.

 

The wobble of the car only tends to happen when it's stationary - it's the anti roll sensor linkage rods attached to the lower front suspension wishbone sticking and seizing up and jerking against the roll sensor mechanism that inputs the signal to the suspension ECU that then commands the pressure to the two anti-roll rams. You need to carefully dismantle the rods attachment and grease them to ensure they're not stiff. You can still buy the plastic shims that locate them for a fiver a set from Citroen as they do wear and get damaged.

 

Another interesting thing I've found about my Activa is failure of the top engine mounting. This isn't the obvious big swing arm donut you can see easily but the smaller bulkhead mounted triangle with a small 30mm donut which totally collapsed on mine. It manifest itself as a rattle/rasp on the overrun or gear changing. Again new part from Citroen for 27quid!!

 

Andrew

[wizzymichael]

Hi Michael

 

I've only recently got my head around my Activa a bit more and have found a massive wealth of info on Xantia/Activas here:

 

http://www.frenchcarforum.co.uk

http://z7.invisionfree.com/ActivaNet/index.php?act=idx

 

The Activanet guys have experience with dump valves/performance mods etc.

 

There are 10 spheres on an Activa.

 

2x corner spheres front

1x centre hydractive front accumulator

1x Activa SC-CAR front accumulator

1x main system regulator accumulator

 

2x corner spheres rear

1x centre hydractive rear accumulator

1x Activa SC-CAR rear accumulator

1x Anti sink

 

To look at with a casual glance all the spheres will look the same - ie round and green!! ;-)

However, the area of gas volume can vary between various parts of the Activa and other Citroens from 400 to 500 and IIRC 600 for Ds and Cx Safari models. Then there's the gas pressure inside the sphere which can vary from 40bar to 70bar so a lot of variables come into play here too. Combine this with the accumulator sphere being VERY different from the conventional corner spheres in that there is no jet or orifice in the threaded end of the sphere compared to the tiny 1.3mm (or thereabouts) opening on the corner. The accumulator has a big open bore on it's threaded end the diameter of the thread and an inset jet of a far greater diameter - approx 8mm.

 

I'd expect the spheres will heat up, the fluid is being pumped around the hydraulic system via the pump bolted onto the engine so I don't think the heat will cause any issues - it's an oil after all! Try using Hydraflush fluid cleansing solution that's sold in 5l to keep the system in good order before using fresh LHM.

 

The wobble of the car only tends to happen when it's stationary - it's the anti roll sensor linkage rods attached to the lower front suspension wishbone sticking and seizing up and jerking against the roll sensor mechanism that inputs the signal to the suspension ECU that then commands the pressure to the two anti-roll rams. You need to carefully dismantle the rods attachment and grease them to ensure they're not stiff. You can still buy the plastic shims that locate them for a fiver a set from Citroen as they do wear and get damaged.

 

Another interesting thing I've found about my Activa is failure of the top engine mounting. This isn't the obvious big swing arm donut you can see easily but the smaller bulkhead mounted triangle with a small 30mm donut which totally collapsed on mine. It manifest itself as a rattle/rasp on the overrun or gear changing. Again new part from Citroen for 27quid!!

 

Andrew

[wizzymichael]

thanks for the reply.will look over the next day or so, thanks for the link to the activa site, spent ages on there swatting up ,

cheers michael