C5 suspension fault

[philcat44]

Hi Marc

Followed information in the link above, no bubbles or rising or lowering of fluid. Car still wont rise from its lowest setting. I have tried applying a bit of air pressure to the top of tank as suggested but still no luck. pulling my hair out and I haven't got much left. Any other ideas?

[GiveMeABreak]

I suggest you leave the engine running and allow enough time for the system to pressurise. Replace the LDS cap when the engine is running and make sure the suspension is set to normal position for the moment. If you can hear the pump running it is at least operating - but can take some time to pressurise. If it is still not rising after 5 minutes or so and the pump is still trying to run, then it needs some pressure in the system to prime it.

However if the car is still not rising after 5 minutes, I would be careful that the pump doesn't overheat. It shouldn't ever need to operate for very long under normal operating conditions - only for height adjustment and height correction.

[philcat44]

Thank you again for your help and suggestions away from home today but will try that tomorrow and let you know how I get on.

[James6677]

Hi! How is the leakage ?
I have the same problem with my C5(2004,3.0,V6). There was a leakage from a nut of a high pressure pipe which leaked off almost all the LDS in the system . I fastened it and the leakage disappeared, but the suspension didn't react after the refilling of LDS . I'm waiting for your result. Good luck!

[GiveMeABreak]

If the LDS has been almost entirely lost then the circuit which is pressurised needs to have some pressure applied at the tank neck in order to help prime the system. Once it gets going the pump will be able to do its job. It will need bleeding too, otherwise there will be air in the system.

There is a tool that is used to do this, but what many do is use a piece of inner tube with the valve on from a bike, cover the LDS filler neck and use a bicycle pump. Pressure needs to be 0.5 Bar or about 7 PSI to start it off with the engine running and suspension on normal height.

The reason why some people need to do this and others don't will depend on how much air is in the system and how much fluid was removed....

[James6677]

Great thanks Marc ! I will try it. Btw, I can here the pump hissing for a while after I switch off the motor. Is this normal? Does this mean that the pump is still good?

[GiveMeABreak]

Hmmm.... Have you double checked all the pipes are clamped ok - and more importantly was the system ever de-pressurised using the bleed screw on either the Front or Rear Axles? There are 2 choices when the system is going to be de-pressurised. You can use Lexia / Diagbox to electronically handle the process automatically, which fully de-pressurises, or you can opt to de-pressurise either the front or rear axles using the bleed screw on the front or rear hydraulic blocks. If this was done and either of the screws were not fully tightened afterwards, then the car will never be able to be pressurised again.

Whatever you do, don't get underneath the car without it being supported independently as with this sort of issue the car could come crashing down all of a sudden and crush you.

[philcat44]

Marc
Thanks it was still suffering from an air lock. Whilst a bicycle pump did not deliver enough pressure I can across another article about the tank being split by the car being jacked and dropped down without the capped being removed. As a result we jacked up the front and back to get the car to dropped its wheels hoping to release the pressure in the system. The level of the Hydraulic oil remained the same. So we gave the bicycle pump another go and when we dropped the car slowly this time the oil started to drop. It required a further 1/2 litre to bring it up to the correct level. Then success it all worked fine. thank you for all the help

[GiveMeABreak]

Ok, good. Bear that in mind when getting tyres changed in future - always raise suspension to high first and remove LDS tank cap if raising with wheels off the ground and hanging freely.