Hydractive faults

davewithington · Post by **davewithington** » 29 Jul 2010, 17:10

OK Jim, ref recent correspondence we've had, you said my high tick rate could be due to a Hydractive fault.

Currently, I'm stuck in hard on the Xantia (sounds a bit rude that, says the missus) and the back end drops quickly once the engine stops. Regulator ticks about every 5/6 seconds.

Could this be an internal leak? What do I need to look at/prod/hit with one of my selection of hammers?

KevMayer · Post by **KevMayer** » 29 Jul 2010, 17:26

It sounds like you have a weak small spring in your rear electrovalve.

This small spring is needed to push the needle forward to block off the outlet/bleedback port inside the valve in order for pressure to build up to make the suspension switch to soft. So, you'll get continuous pressure bleed back to the reservoir, hence the fast tick rate, and you won't get soft mode.

The solution is to remove your electrovalve and strip it down so you can stretch the small spring.

Jack the Xantia up, put it on axle stands at the rear, take out the spare wheel carrier, run engine and put suspension on low, crack the relief valve on the regulator then get underneath and remove the whole rear hydractive block.

It sounds worse than it is. It's easy as long as you work methodically and have plenty of patience.

To open the electrovalve it is often suggested that it will help if you bake it in a low oven at say 75 degrees C for 10 mins to soften the thread lock.

andmcit · Post by **andmcit** » 29 Jul 2010, 17:50

An additional reference for the feed returns to the LHM reservoir here:

will help determine which circuit is leaking and feeding lots of fluid back.

Andrew

KevMayer · Post by **KevMayer** » 29 Jul 2010, 17:54

Here's a picture of an electrovalve in pieces.

The needle is in the centre.

The small spring is the one on the right. This just needs to be stretched to increase it's length by say 30%.

Post by **CitroJim** » 29 Jul 2010, 20:32

Hi Dave,

Well there you go, Kev has done a textbook job here for you

Exactly what I was going to say!!!

Normally, the valve only leaks in soft mode but it's likely it's leaking so well that soft mode cannot be selected as it needs both an electrical signal and hydraulic pressure and the leak may bleed too much of the latter away to shuttle the valve over fully.

best way to assess the leakage is to pull off the spare wheel carrier (just one 13mm bolt) and slip off and block the leakage return pipe on the electrovalve itself. Then attach a ;length of aquarium hose to it into a clean container. Clean so that you can re-use the resultant LHM!

A good valve should only sput on hard to soft switching and vicky-verky.

You can test in hard mode only by pulling Fuse 8 (20A, LH side of the engine bay fusebox) with the ignition off. This cuts power to the Hydractive ECU and will result in permanent hard mode. In this condition the valve should leak very little and also the back end should not drop.
With luck the valve will unscrew from the hydractive sphere block by applying a good spanner to the top 16mm hex. If not, it'll start to come apart. Carry on disassembling but being very careful not to loose the innards as thise springs can be a bit lively.

Then, with the top, innards and coin removed, a 24mm deep socket can be used to remove the lower half or better, leave it in-situ and do Kevs spring overhaul work in place. It's a bit delicate but not as bad as it looks. Just have a large sheet of white paper under your work area in case a spring makes a bid for freedom!

As you say Kev, the sphere block is easy enough to remove fully but you do need very good 17mm and 9mm flare nut spanners to avoid rouning the hexes. I find the 17mm ones can be tight...

The MK1 sphere blocks don't have bleed nipples on them. That was very welcome MK2 innovation

Let us know how you get on Dave...

cachaciero · Post by **cachaciero** » 29 Jul 2010, 23:32

Very interesting I wonder if the C5 electrovalve can suffer the same problem, might explain why mine is in semi hard mode on the front.

cachaciero

davewithington · Post by **davewithington** » 30 Jul 2010, 08:45

I like the phrase "the spring can be a little lively". Having had experience of lively springs of all sizes over the years I tend to dismantle things very slowly these days.

Sounds good.

I'll pull the fuse this morning on my way out and see what effect it has.

I feel this is the correct diagnosis as when the LHM return on the front RH strut started leaking, LHM was flowing out of the return loom towards the strut, not the other way.

I'll be back.

citroenxm · Post by **citroenxm** » 30 Jul 2010, 10:13

Hmmmm Im not so sure on the Rapid Sinking on switch off is anything to do with the Electro valve or Block!

I had a 1995 M reg Xantia VSX, anti sink, and found that after engine stop, the back would be on the floor within 30 seconds! It always came up though, and I changed everything that was: Anti sink valve, electro valve and Block, regulator, pump, all from a car that did NOT do this.. I never got to the bottom of it!

I eventually sold the car in that state, with the assumption that, she always comes up, and the buyer was happy with that!

When I mean sink too, I mean faster then a Sinker Xantia aswell!!

Paul

Post by **leithant** » 02 Aug 2010, 02:43

Thanks for the great posts, fellas.

I thinks someone needs to assemble a Hydractive troubleshooting guide and put it up as a sticky. It would be very useful to accumulate all the combined advice from over the years in one easily followed step-by-step elimination
chart or something.

BTW I thought it was generally seen as too risky to pull apart the electrovalve without risking damaging it? You make it sound fairly easy.

The rear end on mine is hard ATM. The spheres aren't that old, but since I got it back from the panel beater after the car got rear ended, it been very bouncy at the rear. When I picked it up it was in the medium-high position, which worried me. Do you think something was damaged by being driven at that height?

Post by **myglaren** » 02 Aug 2010, 06:56

Have you checked the rear height corrector mechanism? Could have been damaged by the collision, or at least reset slightly.

Have a look through here before you start on it.

Post by **leithant** » 02 Aug 2010, 07:19

myglaren wrote:Have you checked the rear height corrector mechanism? Could have been damaged by the collision, or at least reset slightly.

Have a look through here before you start on it.

Nice guide.

It all seems to be fine to me - normal height etc.

It was riding ok in the few weeks between the accident and the repairs BTW. Even though the spheres aren't that old, I think I'll take them off and get them tested, before looking at the electrovalve.

PS apologies for hijacking the thread!

Post by **CitroJim** » 02 Aug 2010, 16:24

leithant wrote: I thinks someone needs to assemble a Hydractive troubleshooting guide and put it up as a sticky.

There is one within the Activa Buyers Guide. Just ignore the Activa-specific bits.

I've had a few electrovalves apart without issue, just go very carefully and you'll be OK.

Post by **leithant** » 03 Aug 2010, 00:51

Thanks, Jim.
I noticed there you were clear about a correctly functioning Hydractive car should be more comfortable than standard. There is a bit of debate about this on Aussiefrogs, but technically iit is quite obvious, but I guess that many HA2 cars aren't running as they should these days!!

davewithington · Post by **davewithington** » 22 May 2011, 17:55

Well I've finally got round to doing my rear electrovalve today. Before I removed the solenoid, I checked the flow from the return pipe. In soft mode, fluid just flowed unchecked. After removing the block and stretching the springs, no flow!

Have to say what an easy job it was, everything came apart as it should without a fight, and went together again.

Brilliant! Tick rate is much better, nearer 12 seconds than the three I wsa getting before, rides better, goes up quicker and stays up longer (my wife was impressed)

Post by **CitroJim** » 22 May 2011, 20:33

Excellent news Dave