anti sink

[allanmc]

My 2 series Xantia HDI sinks down if left for a few hours am I right in thinking that I need an anti sink sphere
allan

[Xaccers]

Possibly.
You see, despite it's name it's actually just a rear accumulator.
The combined pressure of the rear corners and anti sink sphere keep the anti sink valves closed.

It works like this, the valve is opened by higher pressure from the pump side of the system, when the pump stops the pressure in the spheres the other side keep it closed.
If the pressure in the spheres isn't strong enough, and pressure leaks away.
With the engine idling, what's the tick rate of your regulator at the front of the car with the accumulator sphere screwed into it?
If it's less than 30 seconds it needs replacing, which would suggest the rear one also needs replacing.

Another cause could be an internally leaking suspension ram, where lhm gets past the piston and returns to the resevoir.
If the car has hydractive suspension then on of the hydractive valves could be leaking internally too.

[CitroJim]

The most usual cause of sinking is ruptured corner spheres. On a hydractive car the fact they're ruptured is almost undetectable except by the sinking that occurs.

Also, another cause can be a ruptured main accumulator; this causes an immediate loss of pressure in the main hydraulic circuit and prevents the anti-sink valves from snapping shut in a timely manner. A ruptured anti-sink, as Xac says, will also contribute to this.

[jacksun1987]

M,y black tzd bx used to go frount up first then back. When i tryd selling it it took 10 to 15 mins to rise. But a couple of hours before i pumped it up to change the wheels. And it went up ok. Well better then normal. Somtimes the back end used to go up then for about five mins it was pointing in to the ground. Only happerned when i lowerd the car. Then when i put it in to normal driving it was like it was having a niose dive.
The thing what peed me off the red txd which i had had no probleerms what so ever. It ticked ok it went up and down really fast was a comfy motor. Comperd to the spine breaking not so well handling of the black one. But my red txd had a mijor hydrolic failor on the motory what killed it. I bet the rubbish suspension on the black tzd still works.
Its wierd how one car has tones of faults but still goes. Then you get a car whic has not has many. Then in one bad day its the end of it.

[allanmc]

I checked and the tick rate is 9 sec. so I am going to buy a new Accumulator and as Xac said I would be better getting the one for the rear as well, I will get a flare spanner before I start and also a seal, just looked through the receipts I changed the rear spheres 2005 and the front 2007 and have done about 50.000 mls. since 2005, dont know whether to change the lot
allan

[Xaccers]

The trick to the anti sink sphere is letting the sphere do the work.
Hook the 9mm flare spanner onto the pipe nut behind the sphere, turn it as much as you can just to get it going, then with the spanner still on the nut, screw the sphere out of it's socket.
It should then also screw off the nut.
When you fit the new sphere, still use the new o-ring even though the socket has no recess.
It stops the sphere rusing to the socket.

[allanmc]

Should have asked, I added Hydraflush in 2005 and then replaced the LHM shoul I be doing this again
allan

[Xaccers]

Should have asked, I added Hydraflush in 2005 and then replaced the LHM shoul I be doing this again
allan

Not sure on the time limit, but if I remember correctly it should be replaced at 36K intervals with hydroflush being used at 72K intervals

[allanmc]

Thanks Xac

[allanmc]

Changed the 6 spheres yesterday and I am going to fill system with Hydraflush, should I bleed the brakes now or wait until I put in the new LHM
allan

[CitroJim]

No, bleed the brakes after putting the hydraflush in and bleed until the hydraflush flows out clean. Then re-bleed once you refill with LHM...

[allanmc]

Thanks Jim