C5 X7 suspension jerky movement

[daveB69]

Hi,

I just replaced the left front suspension strut on my 2008 C5 Tourer as it started leaking badly, everything went fine and when I test drove the car it was smoother than ever, no problems. However today, 2 days later, the front of the car now doesn't rise and fall smoothly when the height is changed, instead it goes up in jerks, as if it's sticking.

What could cause this? The fluid level seems ok.

Dave.

[Stickyfinger]

Did you bleed the system correctly after fitting the strut ?

[daveB69]

I did the procedure of raising and lowering the car and then turning the steering from lock to lock several times - I'm not sure if I need to do more than that for a strut replacement?

[Kees]

From where did you buy the strut?
Some buy Chinese imitation from ebay and some of them gives problems.

[Stickyfinger]

I did the procedure of raising and lowering the car and then turning the steering from lock to lock several times - I'm not sure if I need to do more than that for a strut replacement?

Worth doing it some more....it can do no harm.

Have you got access to a Lexi/Diabox system to see what the height controller is doing ?....on C5X7 these are potentiometers and can fail in similar ways........

[Kees]

@Stickyfinger: No these are not potentiometers, they are hall sensors, so there are no parts inside that make physical contact.

[Stickyfinger]

@Stickyfinger: No these are not potentiometers, they are hall sensors, so there are no parts inside that make physical contact.

Correct,,,,my bad.....they still can fail/be intermittent/covered in crap etc.....

[daveB69]

Thanks for the suggestions.

I will try the bleed procedure some more, and check the fluid level again. I was left with the feeling that more fluid came out when I depressurised it via the front nipple, and from replacing the strut, than went in when I topped it up. But I didn't measure it so can't be sure.

The new strut was from an ebay seller I'd used before, not sure of the origin. I went mid-price, rather than absolute cheapest,on the basis that low cost is unlikely to equal high quality! Seemed well made.

I don't have access to Lexia/Diagbox, I borrowed my neighbours Topdon 600S which I was surprised to find allowed me to depressurise the suspension and set the reference values for the suspension height, but I'm not sure what else. I've still got it so I'll plug it in and have another look.

I wouldn't be surprised if there was a problem with the height sensor as the front suspension has never behaved quite right since I got the car in March, it sat too high at the front until I managed to adjust it, and it only goes to 3 different heights at the front whereas the back end has 4 positions. It was always smooth though.

Dave

[Kees]

I think it's still better to focus at the strut, as I say before, there are other people here on the forum with problems when they replaced the struts from E-bay, maybe it's better to become one from Poland.
I think the problem is the materials they used for the seal inside, maybe this one becomes thicker by the lds fluid and is responsible for the sticky movement.

[Stickyfinger]

Personally I would rule out an air lock/faulty height sensor before removing and exchanging a full strut .......choices egh

[Kees]

So, gif an explanation, that the suspension works fine for 2 days after repair, and then suddenly is there air in the system/ height sensor problem.
Look at a simple way to just one strut, there's a piston inside, above this a column lds fluid and above this a sphere.
The piston moves up/down from the road conditions, so if there's a problem with the suspension after 2 days
You can make yourself difficult to look in a different direction, but 99,9 % the strut is faulty!

[daveB69]

Well, over the last couple of days of driving the jerky movement seems to have reduced, and today I'm not sure it did it at all. Something just bedding in?

I'll keep an eye on it, I'm not going to pull the strut out again without hard evidence that there's something wrong with it. It was an awkward time-consuming job that I don't want to repeat until the other side needs doing!

[PaulC5]

I do not know if this would help but on our C5 I used to grease the height sensor pivot ball joints to keep the suspension moving smoothly.

[daveB69]

It's worth a try, I'm thinking of replacing the height sensor anyway.