Xantia HA2 problem

DoubleChevron · Post by **DoubleChevron** » 14 Jul 2005, 06:28

Hi Guys,
don't take this the wrong way ... But have your pressure tested the H/A sphere ?? If it's flat there will be no difference between hard and soft mode. I'd remove the sphere, check to ensure there is no valve in it (ie: make sure no-one has fitted an incorrect sphere there), then test it for pressure.
seeya,
Shane L.

Post by **Peter.N.** » 14 Jul 2005, 14:05

I concur. Most people ignore the centre sphere, especially as they are not very easy to get off.

bernie · Post by **bernie** » 15 Jul 2005, 01:27

I've changed all spheres for new from our host's.
I swopped the rear HA sphere back to the original but no difference.
I've been thinking about trying to force the soft mode and come to the conclusion, as the solenoid has a live feed, I will remove the piston from the solenoid and thereby lhm will then enter the HA valve.
This should simulate soft mode providing it's not the HA valve that has seized

bernie · Post by **bernie** » 21 Jul 2005, 15:52

I'm playing around this morning to trace this fault.
I've got very little lhm pressure getting to the electrovalve (ev)with the rubber pipe disconnected. System is under pressure on high setting.
Open bleed screw on ev and about 1/4 pint comes out, full of air, then stops after click.
I then notice the rear HA sphere can be turned by hand indicating no pressure behind it, so I remove it. No fluid loss. Car stays up.
I then open a door, whoose, car drops, fluid everywhere from ha block. rear spheres loose so ev and ha block must be working but why is the ride so bloody firm?
Wits end coming up fast

bernie · Post by **bernie** » 21 Jul 2005, 16:37

I've studied the ha diagram and it would appear the 1/4 pint of lhm came, not from the security valve, but from the rear of the ha sphere resulting in the sphere being loose and removable.
But if that is so why did'nt the pressure from the 2 rear spheres come into circuit?????
Wits end nearly here

bernie · Post by **bernie** » 21 Jul 2005, 16:45

bernie · Post by **bernie** » 21 Jul 2005, 17:11

Anyone know where the security valve is located?

Mandrake · Post by **Mandrake** » 21 Jul 2005, 17:13

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by bernie

I'm playing around this morning to trace this fault.
I've got very little lhm pressure getting to the electrovalve (ev)with the rubber pipe disconnected. System is under pressure on high setting.
Open bleed screw on ev and about 1/4 pint comes out, full of air, then stops after click.
I then notice the rear HA sphere can be turned by hand indicating no pressure behind it, so I remove it. No fluid loss. Car stays up.
I then open a door, whoose, car drops, fluid everywhere from ha block.
<hr height="1" noshade id="quote"></blockquote id="quote">
Just wondering, do you have a death wish ? [:D]
Unscrewing a sphere while the system is pressurized is just asking for trouble... it's normal for the hydractive valves to switch to soft mode when a door is opened - so all the oil pressure from the side spheres would have raced out through the centre sphere mounting as soon as the valve opened.
If you were under the car without ramps this is a potentially fatal situation...
I've just bought a VSX a couple of days ago and I'm not convinced that the HA2 system is fully behaving itself at the back, so I'll be going through and diagnosing the system in a few days, so I'll let you know any tricks or tips I figure out in the process [:)]
At first I thought the rear hydractive sphere was flat, but now I'm not so convinced... it is also suffering from seemingly being in firm mode all the time at the back - even with the door open or key on while stationary (which should be soft mode) the back still feels fairly stiff with very slow damping, while you can tell the difference when the front switches....
Regards,
Simon

bernie · Post by **bernie** » 21 Jul 2005, 17:40

No DEATH wish yet.
The car is on ramps and axle stands.
The thing is you CANNOT unscrew a sphere easily whilst there is system pressure but I did because there was NO pressure behind it when there SHOULD have been.
At least I've proved the EV works when the door opened.

Stempy · Post by **Stempy** » 21 Jul 2005, 22:33

Why not attach an indicator light to the electrovalve. It should be fairly easy to splice into the feed wire and run another wire into the cabin and attach an LED to it. You will then have an indication as to whether the EV is active or not as you are driving.

xantiav6 · Post by **xantiav6** » 21 Jul 2005, 23:19

<blockquote id="quote">quote:<hr height="1" noshade id="quote"> it is also suffering from seemingly being in firm mode all the time at the back - even with the door open or key on while stationary (which should be soft mode) the back still feels fairly stiff with very slow damping,<hr height="1" noshade id="quote"></blockquote id="quote">
Slow damping indicates that it is in soft mode. Maybe your problem is with some general stiffness in one of the suspension components?

Mandrake · Post by **Mandrake** » 22 Jul 2005, 02:13

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stempy

Why not attach an indicator light to the electrovalve. It should be fairly easy to splice into the feed wire and run another wire into the cabin and attach an LED to it. You will then have an indication as to whether the EV is active or not as you are driving.
<hr height="1" noshade id="quote"></blockquote id="quote">
Exactly what I was planning to do [:D]
Regards,
Simon

Mandrake · Post by **Mandrake** » 22 Jul 2005, 02:19

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by xantiav6

<blockquote id="quote">quote:<hr height="1" noshade id="quote"> it is also suffering from seemingly being in firm mode all the time at the back - even with the door open or key on while stationary (which should be soft mode) the back still feels fairly stiff with very slow damping,<hr height="1" noshade id="quote"></blockquote id="quote">
Slow damping indicates that it is in soft mode. Maybe your problem is with some general stiffness in one of the suspension components?
<hr height="1" noshade id="quote"></blockquote id="quote">
How do you figure that slow damping means its in soft mode ? I'm talking about the rebound rate - pressing down the back and releasing it causes it to rise back to the original height over nearly a second, which is the result of a very small damper bypass hole (which is 0.6mm on a rear hydractive sphere) and when its in soft mode the damper hole should be effectively larger because you now have two damper orificies in parellel for the oil to travel though.
Of course it could just be that the corner spheres are nearly flat and its only riding on the hydractive sphere, but I can't seem to notice any difference in the bounce test when it switches from soft to hard, while I can notice an obvious difference in the front.
I havn't had a weekend yet to have a decent look at it, so we shall see....
Regards,
Simon

xantiav6 · Post by **xantiav6** » 22 Jul 2005, 03:14

No, The slow rebound is due to the low spring rate of the HA sphere. The corner spheres have a much higher spring rate and a faster rebound (despite the smaller damping holes).

Mandrake · Post by **Mandrake** » 22 Jul 2005, 06:55

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by xantiav6

No, The slow rebound is due to the low spring rate of the HA sphere. The corner spheres have a much higher spring rate and a faster rebound (despite the smaller damping holes).
<hr height="1" noshade id="quote"></blockquote id="quote">
I think we're talking at cross purposes here, and not defining damping rate in the same way.
The springing rate in hard mode is not that different from a standard car - for example the front HA spheres are only 45 bars compared to 50 of a non-HA2 (only a 10% difference, and this is comparing 450cc spheres) the big difference is the 0.7mm hole compared to a 1.5mm hole in the standard sphere, giving a very different damping rate. (Only about 20% of the hole area)
Also the spring washer valves themselves may be adjusted differently as well. In any case it is primarly a damping valve difference and the gas pressure difference is only a small contributor.
The problem I'm noticing is that it is at the same time quite stiff, (I can only push it down an inch) but the rebound is very slow - it takes about a second to fully return the the static height.
This is indicative of a very small damper bypass hole in the main spheres (normal for HA2) and the hydractive sphere not working.
If you make the bypass hole too big on a standard model (and don't change the gas pressure) the rebound becomes faster and overshoots. If you make the hole quite small the springing feels a bit stiffer even though it is not, and the rebound becomes much slower...been there, done that with tweaking the damping hole on spheres on non-HA2 models, so I've got a pretty good idea of the effects of different hole sizes...
Regards,
Simon