Norwegian activa won`t rise or fall..

HaraldG · Unread post by **HaraldG** » 11 Jan 2011, 18:21

Continued from http://www.frenchcarforum.co.uk/forum/v ... 716#253716

Now, this car is a low-milage project I bought. I considered using the engine for my other activa (timing belt snapped), but the
car is in much too good shape (accept for hydraulics) to become a donor just yet.. I hope you will continue helping me as I
am not in the habbit of giving up.. ( or maybe I got somekind of manic desease only known to citroen home mechanics?

)
Anyway, I really want to understand this car better!

Sooo... I have done some more fumbling around the activa today.

I altered the anti-rollbar-rod; turned it, so that I at leased could mount the plastic back on again..
It was`nt tightened very well, and I think it might have slipped out of position..

I then greased and loosened the rear height corrector links.

I started the car (still standing on jack stands, no wheels on the ground) and put it in the highest position on the lever.
It took about 10-15 minutes to build up enough pressure for the pressure-regulator to "tick in" and the "STOP" sign to go out.
Pressure regulator cyclus was now around 17 seconds.. (some heavy leaking internally?)

When opening and closing the pressure-release bolt on the regulator, it now only took 3 seconds to refill the acumulator.
I guess the pump is fine..?

I turned of the car, still in highest position on jack stands, and a clear "hissing" sound came from somewhere under the bonnet.
It "hissed" loudly for about 15 seconds (!) I started again and it now only used half a minute to rebuild the pressure. When turning of I
found the hissing coming from the activa corrector valve next to the height corrector. Can this be the leak?
In the activa valve?

I lowered the car down from the jack-stands on to its wheels still with the lever in highest position.. When starting the car the "STOP" light
wouldn`t come of and the pressure regulator wouldn`t tick in. It won`t build up pressure while standing on its own.

After a while I tried lowering it to the normal position..
The front came down to near-perfect position this time but the rear was stuck in highest.
I turned of the engine after a while and the hissing noise was still there but only lasted for 7-8 seconds, probably because of
less pressure in the system.

When shifting the lever to lowest, only the rear would sink. The front is stuck in "normal", but without normal suspension (its hard).

Can activa-linkages out of position cause massive internal bleeding through the activa-corrector valve?

I think the activa spheres might be out of date too..

Does something in the hydraulic system need high pressure to make the car sink??

This was a long posting.. Sorry bout that.

Help me fix this activa, please

Unread post by **CitroJim** » 12 Jan 2011, 18:00

Hi Harald,

The fundamental problem seems to be an inability to build sufficient pressure.

The Activa does take a longer time to build pressure than a normal Xantia but not 10 minutes! This is the first area to begin investigation; why it takes so long.

It could be the pump and there are tests you can do. Firstly though it might be caused by air leaks on the suction side of the pump, air entering the pipe between the LHM reservoir and the pump. If sufficient air does enter then the pump efficiency goes right down. Often this problem is seen in very heavy steering and lots of air bubbles in the LHM reservoir. The pipe between the LHM reservoir and the pump can split and not actually leak LHM.

With the engine idling, you should see fluid movement in the LHM Reservoir but few, if any, bubbles.

Whilst at the reservoir, it is a good idea to check the filters within. If they are very badly clogged with dirt, this can affect the pump efficiency.

Next, you must check the Main Accumulator, the Activa Accumulator and the anti-sink sphere (which is also an accumulator). If you have any doubt on these, replace them. With good accumulators, the STOP light should go out after about 30s. Also, the regulator tick should be in excess of 30s and preferably in excess of a minute. The Activa is very sensitive to sphere condition and many strange effects will be seen if any of the accumulators are flat.

Next, disable the Hydractive soft mode by pulling out F8 in the engine bay fuse box (with ignition off) This cuts power to the Hydractive ECU and keeps the suspension in hard mode constantly. If everything now performs normally, you have a large internal leak in a Hydractive electrovalve (stiffness regulator valve). Sometimes this leakage does sound like a hissing noise.

Otherwise, the leak could be in the brake dosuer valve and this can be checked by disconnecting its leakage return pipe and seeing how much LHM runs from it. A heavy flow suggests the valve is suspect.

The rear will be staying hight as the anti-sink valve is remaining closed on high due to the low main circuit hydraulic pressure pressure. The anti-sink valves will only open when the main hydraulic pressure exceeds that from the suspension spheres.

Roll correctors only normally leak; I've not heard one hissing but the sound may be coming from elseware.

The important thing is to get the regulator tick rate well above 30 seconds and I hope the notes above will help find the cause.

My first checks would be to check the feed to the pump for air leaks followed by testing/replacement of all three accumulators.

HaraldG · Unread post by **HaraldG** » 12 Jan 2011, 22:06

Hello, Jim. Nice to hear from you

It could be the pump and there are tests you can do. Firstly though it might be caused by air leaks on the suction side of the pump, air entering the pipe between the LHM reservoir and the pump. If sufficient air does enter then the pump efficiency goes right down. Often this problem is seen in very heavy steering and lots of air bubbles in the LHM reservoir. The pipe between the LHM reservoir and the pump can split and not actually leak LHM.

With the engine idling, you should see fluid movement in the LHM Reservoir but few, if any, bubbles.

I have tried connecting a hose between the tank and the pump but it just shrunk, causing the pump to work very hard. I will try with a new tank lid and pipe from my other activa. I haven`t seen a lot of bubbles earlier though. A little bit when turning the steering wheel. But today when testing the car some more, I noticed there was a lot of foam in the tank after pressing the brakes repeatedly

The filters are clean and the LHM is new.

Next, you must check the Main Accumulator, the Activa Accumulator and the anti-sink sphere (which is also an accumulator). If you have any doubt on these, replace them. With good accumulators, the STOP light should go out after about 30s. Also, the regulator tick should be in excess of 30s and preferably in excess of a minute. The Activa is very sensitive to sphere condition and many strange effects will be seen if any of the accumulators are flat.

Again I`ll use my other activa for donor.. The main accumulator and anti-sink sphere are just 6 months old. I`m not sure how old the activa accumulator is, but I think it`s ok.. By activa accumulator, i guess you mean the one in the front?

Next, disable the Hydractive soft mode by pulling out F8 in the engine bay fuse box (with ignition off) This cuts power to the Hydractive ECU and keeps the suspension in hard mode constantly. If everything now performs normally, you have a large internal leak in a Hydractive electrovalve (stiffness regulator valve). Sometimes this leakage does sound like a hissing noise.

I`ve tried disabling the hydractive fuse and do citrobatics. Didn`t help

Otherwise, the leak could be in the brake dosuer valve and this can be checked by disconnecting its leakage return pipe and seeing how much LHM runs from it. A heavy flow suggests the valve is suspect.

Can this be the source of the foam too?

I`m not sure which return pipe this is..

The rear will be staying hight as the anti-sink valve is remaining closed on high due to the low main circuit hydraulic pressure pressure. The anti-sink valves will only open when the main hydraulic pressure exceeds that from the suspension spheres.

Soo..

The parts of the system which are supplied through the anti sink valves alone; are probably not sources of failure...? Are the activa parts on "this side" of the anti sink valves?

So, this is why it gets stuck in different heights.. (My brain is almost frying)

Roll correctors only normally leak; I've not heard one hissing but the sound may be coming from elseware.

Maybe I`ve misplaced it.. Can the any of the brake parts make sounds like this?

I also tried jacking the front left side of the car today, with the lever in high position. The "Stop" sign went out but came back on again as soon as the front left wheel got weight on it. I tried from the other side too but it didn`t work there.
Is the left front suspension or the activa-ram "the furthest away" in the system flow/pressure? Or weakest when pressure fails?

Thanks for a lot of help CitroJim

You are really helping me here

lefgrter · Unread post by **lefgrter** » 13 Jan 2011, 07:46

Foam in LHM tank was the primary problem of my Activa too. After many many study hours in the forum i managed to solve it by changing the HP pump. It had a tiny hairline crack behind the pulley (impossible to see it until removal of pump). Due to this foam in tank, i had major problems in brake lines as i was forced to bleed the brakes every 2 days to keep the car drivable. The good thing is that i can bleed brakes now with car on the ground and all wheels on...

You can read my posts at

http://www.frenchcarforum.co.uk/forum/v ... c&start=45

Unread post by **CitroJim** » 13 Jan 2011, 16:40

You have carried out some very good tests Harald

I am worried that a test pipe between the LHM tank and the pump squashes flat. Normally, a length of quite thin plastic pipe will do for this test, as shown in one of the pictures in Lefteris's thread. I've never known one to collapse and that it does suggests very much that the pump is trying to suck against a blockage.

That blockage may be caused by the tank lid as the pipe attached to it is open to the atmosphere. If the lid breather hole or the pipe was blocked or there was some kind of obstruction in the tank then I could see a situation where a test pipe may collapse. This is a prime area to investigate.

You did not say if the steering is heavy? I would very much expect it to be very stiff indeed and will give an additional clue.

Lefteris, you make a very good point about a crack in the body of the pump but given the pump is able to collapse a suction pipe then hopefully this is not the problem.

The Activa Accumulator is the one under the batter tray that looks like an anti-sink sphere.

The anti-sink valves are placed between the suspension spheres and the height correctors and isolate the sus[pension from the relatively leaky height correctors when there is no or low main system pressure. The valves will only open up when the main system pressure is high. If the valves do not open, the height correctors will not work and thus the car will either not rise or fall, even on the manual height lever.

The Activa system is supplied from the security valve. This valve lives under the LHM tank and has the STOP light sender attached to it. It's purpose is to ensure the suspension and Activa circuits are only supplied if the main system pressure is high enough; it gives priority to the brakes first so these are always supplied even if the main system pressure is low.

That fact that the STOP light keeps coming on indicates very low pressure and as the Activa circuit is not being supplied with pressure when the light is on, the hissing could be movement of fluid under low pressure within the Activa circuit as the suspension moves. I'd say nothing to worry about...

I agree Harald, the hydraulics do fry your brain a little

A good guide to how it all works and explained in simple words can be found here. Down load it and have a good read. It describes every aspect of Citroen hydraulics, including the Activa system.

Hope that the cause of the suction pipe collapsing leads to the root cause of all your problems

HaraldG · Unread post by **HaraldG** » 13 Jan 2011, 20:34

Hi again

The test with the pipe was done without attaching it to the tank. I just put it in there.. It wasn`t as solid as Lefgrter`s either. It was a garden hose

I guess thats why it was squashed..

The steering isn`t very heavy either..

The anti-sink valves are placed between the suspension spheres and the height correctors and isolate the sus[pension from the relatively leaky height correctors when there is no or low main system pressure. The valves will only open up when the main system pressure is high. If the valves do not open, the height correctors will not work and thus the car will either not rise or fall, even on the manual height lever.

The Activa system is supplied from the security valve. This valve lives under the LHM tank and has the STOP light sender attached to it. It's purpose is to ensure the suspension and Activa circuits are only supplied if the main system pressure is high enough; it gives priority to the brakes first so these are always supplied even if the main system pressure is low.

That fact that the STOP light keeps coming on indicates very low pressure and as the Activa circuit is not being supplied with pressure when the light is on, the hissing could be movement of fluid under low pressure within the Activa circuit as the suspension moves. I'd say nothing to worry about...

Great!

That means I should concentrate on the parts between the tank and the anti-sink valves. At least for now...

The Citroën guide is great reading! thanks! I feel more confident getting the car back on the road now that I got some expert help

!!
It will need some more care before the MOT test ; ABS light (probably sensors), rear muffler, and the "rolling-connector" in the steering wheel needs changing. That shouldn`t be a problem.

I hear some activa-fans don`t recommend hydraflush on activas. They say it causes clodding in the system.. Is that so? I feel the car would do good with a cleanup in the system when the other problems are sorted..

I`ve bought some more fresh LHM and will try to get the job done, changing the lid (included pipe-manifoild) and spheres tomorrow. Looking forward to it

Some more testing too...

Lefgrter: Thats a great post and some really good pictures!! Good
inspiration seeing others succeeding with their "activa-issues"!

HaraldG · Unread post by **HaraldG** » 13 Jan 2011, 20:35

Hi again

The test with the pipe was done without attaching it to the tank. I just put it in there.. It wasn`t as solid as Lefgrter`s either. It was a garden hose

I guess thats why it was squashed..

The steering isn`t very heavy either..

The anti-sink valves are placed between the suspension spheres and the height correctors and isolate the sus[pension from the relatively leaky height correctors when there is no or low main system pressure. The valves will only open up when the main system pressure is high. If the valves do not open, the height correctors will not work and thus the car will either not rise or fall, even on the manual height lever.

The Activa system is supplied from the security valve. This valve lives under the LHM tank and has the STOP light sender attached to it. It's purpose is to ensure the suspension and Activa circuits are only supplied if the main system pressure is high enough; it gives priority to the brakes first so these are always supplied even if the main system pressure is low.

That fact that the STOP light keeps coming on indicates very low pressure and as the Activa circuit is not being supplied with pressure when the light is on, the hissing could be movement of fluid under low pressure within the Activa circuit as the suspension moves. I'd say nothing to worry about...

Great!

That means I should concentrate on the parts between the tank and the anti-sink valves. At least for now...

The Citroën guide is great reading! thanks! I feel more confident getting the car back on the road now that I got some expert help

!!
It will need some more care before the MOT test ; ABS light (probably sensors), rear muffler, and the "rolling-connector" in the steering wheel needs changing. That shouldn`t be a problem.

I hear some activa-fans don`t recommend hydraflush on activas. They say it causes clodding in the system.. Is that so? I feel the car would do good with a cleanup in the system when the other problems are sorted..

I`ve bought some more fresh LHM and will try to get the job done, changing the lid (included pipe-manifoild) and spheres tomorrow. Looking forward to it

Some more testing too...

Lefgrter: Thats a great post and some really good pictures!! Good
inspiration seeing others succeeding with their "activa-issues"!

lefgrter · Unread post by **lefgrter** » 14 Jan 2011, 07:32

The test with the pipe was done without attaching it to the tank. I just put it in there.. It wasn`t as solid as Lefgrter`s either. It was a garden hose Embarassed Smile I guess thats why it was squashed..

Mine was not solid at all... In fact the tube was much softer than gardening hose. It is a kind of hose used as a "water level" for building construction purpose.

And the interesting thing is that my old pump was creating sufficient pressure for the system to work, despite the small crack and for that reason I was confused and could not diagnose the problem easy.
L

HaraldG · Unread post by **HaraldG** » 14 Jan 2011, 17:41

Well then..

Some more updates

Today I checked the return pipes from the brake valve. Just foam

from both returns while pressing the brakes.

I also checked how much flow came from the main return. I messured it to 1,1L pr 15 sek (4,4 L / min) with no air in it.. I don`t know how much there should be, but the oil was nice and green...

I have mistaken the pressure regulator "tick"-cyclus though. The ticking Î`ve heard is the front activa ram moving. It makes a ticking sound when it gets fully ekstended

The tick rate form the regulator is around one and a half minute

sometimes more

(this is when the car is jacked up front left)

The "hissing" is located too.. When I turned the car of (It ran out of fuel, actually

) I searched with a stethoscope. It`s the pipe under the tank with a red arrow pointing at it on the picture :

Terrible picture

Isn`t that the brake valve? This time the hissing went on for quite a long time as the car had been running a long time too..

What should I make of this then...

New brake valve

addo · Unread post by **addo** » 14 Jan 2011, 21:36

Rear anti-sink valve or sphere, possibly?

HaraldG · Unread post by **HaraldG** » 15 Jan 2011, 11:10

Hi, addo. It doesn`t have pressure enough to lift in the front, at all, without help from a jack.. Can the anti-sink valve leak back to the tank?

Does anyone know how much return flow would be excessive? 1,1 L pr 15 seconds when the car won`t lift sounds like a heavy leak somewhere to me...?
What return pipe should I check? Pressure regulator, brake valve or security valve?

The return pipes in the system aren`t very well covered in the Citroën guide either..

My garage is not excactly a great workshop.. More like a cave actually

Dark, frosty and soaking wet

It would have been nice to know where to begin "debugging" before putting the polar gear and scuba equippement back on

Unread post by **xantia_v6** » 15 Jan 2011, 11:34

It could be any of them, but your brake valve sounds like a good place to start. Does it make any difference of you put your foot on the brake?

BTW, just to check the obvious, you are not looking at the return from the power steering are you? that always has a high volume.

Unread post by **CitroJim** » 15 Jan 2011, 11:52

That looks very much like the brake dosuer valve and it will indeed be under the LHM Tank on an LHD car..

Any of the valves under the tank (dosuer, anti-sink and security valve) should definitely not hiss!

HaraldG · Unread post by **HaraldG** » 15 Jan 2011, 12:24

It doesn`t help putting my foot on the brake. (tried that before)

Great! Which pipe is the return from this doseur-valve if I am to check it for leaking? The hissing one? The flow in the main return continues as long as the hissing is there. After I shut the engine of..
Or should I just change it for a new? Are they expencive?

Thanks a whole lot, Jim, for helping me narrowing the search down

If it werent for your help, I would still be looking in the wrong places.

addo · Unread post by **addo** » 15 Jan 2011, 18:46

The doseur is not cheap to buy, however from my observations they wear inside and renewing the seals does not offer much satisfaction.

I would consider making some plugs and caps to temporarily seal off pipes, especially the one from the rear suspension to the brake valve. If this stops the sinking and slow rise then you have an answer.