Hydractive faults

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Seehund
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Joined: 16 Apr 2012, 22:18
Location: Gothenburg & Öland, Sweden
My Cars: Current: 2013 C5 Ⅲ/X7 2.2 HDi 200 Tourer Exclusive.
Past: 1994 Xantia 1.8i Berline, 1995 XM TCT Berline VSX man., 2007 C5 Ⅱ 2.2 HDi 173 aut. Break Exclusive.

Re: Hydractive faults

Post by Seehund »

My XM is a fast sinker in the rear end, and often the regulator doesn't seem to reach enough pressure to tick at all at idle revs (and at higher revs ticks are frequent). All spheres are new, incl. the main accumulator.

I've had a new rear HA sphere on the shelf for quite a while, but the old one refused to come off unless the valve block was removed and put in a vice, which I did today.

I took the opportunity to follow this guide and stretched the small spring a little. Now it seems like the rear end is in permanent soft mode! Could stretching the spring too much cause this? Perhaps my spring wasn't in need of stretching.

The electrovalve buzzes and clicks as it should, there's just no discernible difference in the rear end's softness between the clicks. Oh well, it could be worse, I'm happy it's not permanently hard...
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Mandrake
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Re: Hydractive faults

Post by Mandrake »

Unless you stretched the springs a lot I can't see that it would prevent it working, as the solenoid is quite powerful and should easily overcome even a stretched spring.

I would check to make sure the parts were reassembled in the right order, the inside assembly of the valve is rather confusing and easy to mix up, which is why I took a photo of mine when I had it apart to make sure it went back together right. (The photo at the beginning of the thread is actually mine :lol: )

If you do remove the valve again to have another go, you can test its operation with a source of 12 volts by simply blowing through the ports. With no power connected if you blow into the overflow port (the long skinny black tube at one end) then air should come out the centre port. (the hole drilled in the side of the short tube between the green o-ring and the thread) You should NOT be able to blow into the inlet port (the end of the short tube with the gauze) in this mode, it should be blocked.

With 12v connected the opposite should be the case - the long skinny black overflow port should be blocked, and the port with the gauze should be open.

Two very important warnings for this test:

1) Do NOT run the electrovalve directly off 12 volts for more than 10 seconds at a time, and give it a minute of cool down time in between operations. The coil unit can not handle sustained 12v for any length of time and will overheat and be damaged if you do.

2) It's extremely important to get the polarity right or the built in diode WILL be destroyed. Although from memory the terminals are labeled, I would check the correct polarity like this: connect the electrovalve to 12v through an 18 ohm 10 watt series resistor and measure the voltage across the electrovalve. If the voltage is around 2.5 - 3 volts the polarity is correct, if it's around 0.6 - 0.8 volts the polarity is incorrect. Once you're sure of the correct polarity its ok to directly connect 12v for up to 10 seconds at a time.

To get it to stay activated continuously, connect it to 12 volts via the 18 ohm resistor then briefly short the resistor out to supply the full 12 voltage - this will cause the electrovalve to switch over, you can now release the short across the resistor and the resistor will provide enough holding current to keep it active without it overheating. (The resistor will get very hot though...)
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
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Seehund
Posts: 4
Joined: 16 Apr 2012, 22:18
Location: Gothenburg & Öland, Sweden
My Cars: Current: 2013 C5 Ⅲ/X7 2.2 HDi 200 Tourer Exclusive.
Past: 1994 Xantia 1.8i Berline, 1995 XM TCT Berline VSX man., 2007 C5 Ⅱ 2.2 HDi 173 aut. Break Exclusive.

Re: Hydractive faults

Post by Seehund »

Thanks for the handy tips, Mandrake! Though now I'm loath to take down the damn thing again, it will have to wait. Anyway, before I refitted the exhaust and everything else that's in the way, I checked leakage with a clear hose to the valve's return line. Not a single drop in soft or hard (engine running, fuse F34 removed) mode. I wish I had done that check before I took the valve apart...

Oh yes, I did consult your excellent photo (without which I wouldn't have dared do this), so I'm fairly sure about the order and the way things are supposed to be turned. Would it even be possible to screw the electrovalve fully back together if, say, the needle was put in at an angle and couldn't enter its hole? And wouldn't the valve then leak like hell through the return line in at least one mode?
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