Air bubbles in the LHM gives harsh ride?

steelcityuk · Unread post by **steelcityuk** » 14 Dec 2006, 16:03

steelcityuk wrote:I hope the sphere isn't the fault it was changed only about 3 months ago. Even when just fitted the cycle time was still very short. I see your point but what's the tie in that makes a Hydractive car behave for a short after having it's fluid replaced?

I'm sure we'd all like to get to the bottom of this issue.

Steve.

As you can see ALL the spheres have been changed in the last 3 months so I din't suspect a faulty sphere.

I did the tests seperately. Max height to test for regulator cycle and normal ride height - switch engine off - stand on towbar.

All hydraulics flushed thru with Hydra whatsit too!

Steve.

bernie · Unread post by **bernie** » 14 Dec 2006, 16:26

steelcityuk wrote:
steelcityuk wrote:I hope the sphere isn't the fault it was changed only about 3 months ago. Even when just fitted the cycle time was still very short. I see your point but what's the tie in that makes a Hydractive car behave for a short after having it's fluid replaced?

I'm sure we'd all like to get to the bottom of this issue.

Steve.

As you can see ALL the spheres have been changed in the last 3 months so I din't suspect a faulty sphere.

I did the tests seperately. Max height to test for regulator cycle and normal ride height - switch engine off - stand on towbar.

All hydraulics flushed thru with Hydra whatsit too!

Steve.

What may be causing the excess cycling are your HA valves. Mine were ok but Simon found his were leaking back to tank.
The fault is caused by the needle not closing the return port, when in soft mode, allowing an almost permanant flow back to the LHM tank.
It may have a slight amount of dirt forcing it open that you probably dislodged when you Hydra whatsited it

steelcityuk · Unread post by **steelcityuk** » 14 Dec 2006, 16:45

Ah, so if that's the case if I disconnect an Hydractive valve the car will go into hard mode and then listen for how long the cycles are?

How often does the regulator ball bearing seat fault appear on Xantias?

Thanks.

Steve.

citronut · Unread post by **citronut** » 14 Dec 2006, 18:26

jeremy wrote:Low cycle time? - do you mean too short an interval between cycles?

Usual cause is flat accumulator - cure - change - they are about £20 or so new from GSF and similar outlets. This should be done first.

If its still there then its probably the non-return valve in the regulator which needs re-seating. If the regulator is conveniently placed you can do the job in the car and it costs nothing. (remove accumulator, remove bolt from accumulator mount face, retrieve ball bearing. Stick it back in its hole with some grease, tap it smartly ONCE using a brass punch and re-assemble. You MUST use a brass or similar punch - otherwise you may put a flat on the ball bearing)

Re-seating must NOT be carried out asa substitute for replacing the accumulator. A sound accumulator is essential for the proper functioning of the system.

The car doesn't rise when you do the boot test. What makes you think your accumulator is any good?

Jerramy
this car did not rise with the boot test because it was put fully up on high when running the engine
regards malcolm

Mandrake · Unread post by **Mandrake** » 14 Dec 2006, 19:25

steelcityuk wrote:Ah, so if that's the case if I disconnect an Hydractive valve the car will go into hard mode and then listen for how long the cycles are?

Yeah, try unplugging the cable to the front electrovalve (this will also make the computer disable the rear one) and see if the regulator cycle time increases.

When mine was leaking the cycle time was about 12 seconds with it connected and about 3 minutes disconnected!!! (The leakage was so much that after turning the engine off and leaving a door open you could hear a hissing noise coming from that area for about 30 seconds as it bled away the pressure)

After replacing that faulty valve it was about 3 minutes in both modes.

Of course, there is nothing to stop the electrovalve from developing a fault that leaks in the off mode instead of/as well as the on mode, (since its a double ended needle valve) but on my one at least the leakage was only in the on (soft) mode.

Regards,
Simon

steelcityuk · Unread post by **steelcityuk** » 14 Dec 2006, 19:56

Just to make this crystal clear -

I raised car to max height and checked accumulator cycle time with engine running, no difference still very short cycle time - about 10-15 seconds.

Then lower car to normal height, waited until it had settled, turned engine off, closed door and stood on towbar. The car did not rise.

I have mentioned in a post weeks ago that after turning engine off a noise like a toilet cistern filling (hissing?) can be heard for a couple of seconds followed by a click. Is this the HA valve or the anti sink or what?

I'm really hoping for nice weather this Saturday so I can investigate further.

Steve.

bernie · Unread post by **bernie** » 14 Dec 2006, 20:47

steelcityuk wrote:
I'm really hoping for nice weather this Saturday so I can investigate further.

Steve.

You've got more chance of fixing the Xant than having good weather

steelcityuk · Unread post by **steelcityuk** » 15 Dec 2006, 11:24

Looking at the weather today you could be right!

Steve.

steelcityuk · Unread post by **steelcityuk** » 15 Dec 2006, 16:36

I intend to use a small brass bolt to reseat the ball bearing in the regulator. Should this be a problem?

Thanks.

Steve.

jeremy · Unread post by **jeremy** » 15 Dec 2006, 17:42

If you're using it as a punch only - it should be fine if its about 5 or 6 mm diameter. The ball is 6mm and I think the hole is a bit bigger. You don't want the bolt to go down the side.

The first time I did it I used an old copper MIG welder nozzle held on the end of a steel punch with a Citroen hydraulic pipe seal (convenient bit of tube!) It did work.

Only 1 smart blow should do the job. Many blows may produce overlapping seats which won't seal.

steelcityuk · Unread post by **steelcityuk** » 16 Dec 2006, 12:38

This morning I reseated the ball bearing in the regulator. Following this the cycle time steadily rose to 1 minute 55 seconds. Great or what. So the next job was to disconnect the front HA valve plug and check for corrosion as soon as I did this the ECU put the car in hard mode, just as it should but I also noticed that the pump was pumping all the time (strange clattery sound).When I replaced the HA valve plug the regulator went back to it's old ways of a 10 second cycle.

So my guess is one of the HA valves is faulty, not necessarily the front one. I could check by disconnecting it and loading the ECU with a suitable resistor. A process of elimination. I think that I'll have a look around for a couple of HA valves that I can recon in the meantime so that when I come to do the deed it's a simple swap. And I need a couple of flare nut spanners as non of mine fit. Looks like I need a 8mm and a 16mm.

Anyone got a couple of HA valves they're welling to sell?

Steve.

bernie · Unread post by **bernie** » 16 Dec 2006, 13:22

steelcityuk wrote:
Anyone got a couple of HA valves they're welling to sell?

Steve.

It just so happens that after fitting 2 new (£104 each) valves to my car, I have 2 spare

citronut · Unread post by **citronut** » 16 Dec 2006, 16:44

the flaire nut spanners you require will probably be 8mm and 12mm
regards malcolm

steelcityuk · Unread post by **steelcityuk** » 16 Dec 2006, 17:53

Your right about the 8mm spanner but the other size I need seems to be a 16mm. I tried a 15mm and that was too small whereas the 17mm was too big. So I've ordered these -

http://www.cromwell.co.uk/KEN5821090K?

I also ordered one of these too -

http://www.cromwell.co.uk/KEN5829520K?

Steve.

Mandrake · Unread post by **Mandrake** » 16 Dec 2006, 18:32

steelcityuk wrote:Your right about the 8mm spanner but the other size I need seems to be a 16mm. I tried a 15mm and that was too small whereas the 17mm was too big. So I've ordered these -

http://www.cromwell.co.uk/KEN5821090K?

I also ordered one of these too -

http://www.cromwell.co.uk/KEN5829520K?

Steve.

Hi Steve,

To save you a bit of grief.....

To remove the front electrovalve all you need is a long neck 16mm socket - you'll have trouble doing it with a spanner as its reasonably tight and there is not much swinging room. (Watch out for the radiator! Put a bit of cardboard or foam in front of it!

)

You don't need an 8mm spanner unless you intend to disconnect one of the small hydraulic pipe unions - which you don't need to do to remove an electrovalve. (Good spanner to have anyway though on a Citroen!!)

With the front Hydractive unit you MUST remove the electrovalve before the main Hydractive control block can be removed - although in your case there is no reason to remove the main control block.

At the rear the electrovalve can be removed by itself or first, OR the main control block can be removed first - but once again you only need to remove the electrovalve by itself, so save yourself a lot of trouble and don't remove the whole unit.

Make sure that you open the bleed screw as well as depressurizing the suspension - the electrovalve is supplied by the full system pressure, not via the height corrector, so if you just lower the suspension and proceed to remove it, you WILL have a nasty surprise in store for you....

Another gotcha to beware of - the electrovalve is a two piece unit which is internally held together by loctite. When you undo it from the 16mm nut at the top it relies on that loctite to hold it together and unscrew the base.

If that loctite should break free (or someone has disassembled it before and put it back together without loctite) there is a chance it will come apart with the bottom still screwed into the control block. If that happens you'll have to carefully dismantle it in place without losing any pieces, and then use a large socket (its somewhere around 22-24mm) to unscrew the remaining piece at the bottom. (Careful - the bottom section is soft alloy and rounds off easily)

There is a small chance of the shaft up the middle of the valve snapping if it's extremely tight (just ask Bernie) so unless you like to play with fire (like me

) wait until you have the replacement on hand before removing the original...

One more tip - as soon as you disconnect the overflow pipe from the top of the electrovalve it will start syphoning the contents of your LHM tank out at an incredible rate - so make sure you have a rag in place and a bung ready to block the pipe, unless you want oil all over the place!

Other than that, piece of cake! Good luck!

Regards,
Simon