C4 Picasso does impression of a classic Citroen

alias no.9

Most of you will remember the Citroen BX and some the older CX, GS, etc dropping their arses on the ground when they parked. This was a feature of the Hydractive suspension to assist with loading but I suspect the primary reason was to depressurise the system while parked because I don't recall the XM, Xantia or first generation C5 doing it with the Hydractive II so I'm guessing they figured out how to make the system robust enough to keep it pressurised while parked. Anyway enough waffle, here's some pictures of our C4 Grand Picasso...





It doesn't have a flavor of the old Citroen Hydractive, rather an off the shelf airbag suspension which was fitted to some/all 'Exclusive' trim models.

I did my research before buying and knew there was likely to be future problems but it met the brief on almost every other factor (7 seat MPV with a torque converter automatic and a larger diesel engine).

The plan from the outset was that at the first sign of trouble, I'd whip out the airbags and replace them with the coil spring setup from the lower spec 2.0hdi, the VTR+. So late last week the dreaded 'Suspension Fault - 10km/h max' message arrived. It was dropping overnight but capable of pumping up and remaining stable once started however the risk is that the compressor will fail due to the higher duty cycle which will leave you stranded.

I got the mechanical side of it completed yesterday, more to follow...

CJhaughey

You mean that the slammed look isn't what you were aiming for?:D
Reminds me a lot of the Landrover discovery with the same type of airbag suspension failure.

alias no.9

So I did like the idea of air suspension and the self leveling aspect for stability but it's rare the car would be heavily laden.

With the airbags costing ~€160 each plus shipping, recommended to be replaced in pairs and a replacement compressor coming in at ~€500 plus shipping if that had been damaged, the economics just don't make sense considering I was able to pick up a set of KYB springs for ~€100 from a motor factors and the Bump Stops and Bottom Spring Retainers for ~€70 from Citroen.

Here are the new parts...

alias no.9

CJhaughey wrote: »

You mean that the slammed look isn't what you were aiming for?:D
Reminds me a lot of the Landrover discovery with the same type of airbag suspension failure.

Similar system I think, Wabco pump?

alias no.9

So before I go any further, I can't put enough emphasis on this

Never attempt to undertake work on the underside of a car when it is supported on a jack.

Always use, at a minimum, high quality Axle Stands and wheel chocks for the front wheels if the back is raised and vice versa. For a little bit of additional comfort, put the wheels you've taken off under the sills of the car.

alias no.9

The Lexia/Diagbox Diagnostic Software allows the system to be depressurised, I do have this but I figured since the car was bottomed out, it would not be all that important, I used the switch in the boot to make sure it was lowered to the absolute minimum.

I choked the front wheels jacked up the rear and placed axel stands at both sides and removed the rear wheels. The Airbags are very accessable and very easily removed, a quarter turn and they pop out.



The tube fitting from the pump is a pretty standard style of push fit pneumatic fitting but I'm not sure if it's a standard size, simply push back the collar and the tube will pop out. There are special tools available for this, there are improvised tools (I've seen a 7mm open spanner mentioned) but it popped off by hand quite easily for me.



Here are the offending airbags, one compresses and one expanded, the expanded one is from the side I jacked up first so using the boot controls to depressurise the system was not a complete depressurisation but I removed the compressed one first without any noticeable pressure release and the expanded bag from the other side had a slight pressure release when I popped the tube off.



I was under a bit of time pressure with the Ireland Italy match at this stage, so this is the end of my photo documentation but I may take a few more to supplement the rest of the story even though the car is back on the road on the steel springs.

shietpilot

My friend had a Citroen XM and it used to drop down when the engine was off as well! It wouldn't be a good getaway car anyway, 2 minutes for the car just to get to normal height :pac:

alias no.9

At this point I'll state that if I was confident that the compressor was robust and the airbags weren't twice the cost of a replacement coil spring setup, I'd probably just have replaced them.

I'm leaving the compressor in place with the fuse removed and capping off the airlines to keep it possible to reinstate the air suspension should pricing change which is a possibility on a now obsolete system.

alias no.9

There are a couple of options to fit the coil springs. I've read that if you remove the bottom bolt of the shock absorbers the axel will drop to give clearance to get the assembled spring, bottom retainer and bump stop into position. I'm wondering after the fact if pumping the suspension to the max before depressurising with Lexia would do the same thing. I had a set of coil spring compressers to hand so I used these.

Space is tight with the spring in place, it's recommend to have the very bottom end of the coil pointing backwards, using screw type coil spring compressers will require you to have the head of the bolt high on one side of the spring and low on the other.

In the compressed state this allows the threaded bar of the Coil Spring Compressers to extend beyond the end of the spring and have clearance when putting the spring into position, the 'bolt head high' clamp will go inboard as the spring goes into place with the threaded bar projecting down past the spring seat on the inside while the 'bolt head low' clamp will be closest you with the threaded bar will extend up into wheel arch.

Check for clearance with all adjacent components, especially brakes and brake lines when choosing the positions on the spring to apply the spring compressers.
A picture would tell a thousand words here but I'll try a diagram later but my strong advice is to have a good look at the surrounding components and chassis to see how you're going to get the compressed spring into place with the threaded bars of the compressers extended beyond the end of the spring.

Don't worry too much about access to the head of the bolt, to remove the Coil Spring Compressers, get a jack under the spring seat and compress the spring further and you can pop them off, again make sure nothing is clashing while you do this.

alias no.9

shietpilot wrote: »

My friend had a Citroen XM and it used to drop down when the engine was off as well! It wouldn't be a good getaway car anyway, 2 minutes for the car just to get to normal height :pac:

First rule of getaway cars is keep the engine running...

shietpilot

alias no.9 wrote: »

First rule of getaway cars is keep the engine running...

Something Gareth Hutch's assassins failed to do I think :rolleyes: