C5 X7 Hydraulics

[milleplod]

More reading -

http://www.citroen-owners-club.co.uk/ci ... ion-issue/

Regarding drop links, its not them causing it on mine - 100% certain!

Pete

[Xantippa]

Clonking saund in the front is normal feature on C5 X7. It's caused by too short suspension travel.

[Stickyfinger]

If this is correct, why does/has mine never done this ?

I have and do drive it over bumps, road humps, speed bumps, I have even had the front wheels off the ground over a humpback bridge. I also carry a LOT of weight in the car so it gets a good work-out.

[Xantippa]

You don't drive fast enough.

Sticky, have you ever changed front struts on X7, or has there been leakage?

[xantia_v6]

This is a fascinating topic.

I can't contribute any C5 X7 experience, but I had a jag with a terrible rear suspension thump when coming off a speed bump at speed. The rear suspension had been rebuilt with all new bushings and bearings, and a set of adjustable gas shock absorbers, but no amount of adjustment of the shocks made any difference to the thump.

Eventually I bought a set of genuine Jaguar shock absorbers (which should have been inferior), and the thump completely vanished.

My belief is that the issue on the Jag (and I suspect on the C5 X7) was that the damper blow-off valve - in the rebound direction - was set to too high a pressure, so that on sudden extension, the rebound valve was not opening enough, and the shock absorber was holding the wheels off the ground momentarily.

On HA3+ there are 2 sets of dampers involved (firm and soft mode), I would expect that either damper should be designed to allow enough flow to keep the tyre on the road, but maybe the manufacturing tolerances are a bit fine.

Note that the mass of the wheel and tyre are relevant to this, so if the cars were fitted with heavier wheels than the suspension was tuned for, it could cause this sort of issue.

[bobins]

The trouble with the drop links is that they never really look or feel worn when you inspect them The best way to diagnose them is to have someone in the car with you who knows what duff ones sound like, or to replace them with quality new ones. I've had a genuine parts one start clonking after about 20k, but that was because I had to remove it to do a broken spring - disturbing it was enough to cause it to start clonking.
If I had a front suspension clonk (after going over speed bunmps, etc) and I wanted to sort it out, I'd be tempted to just replace the front drop links as they are (relatively) cheap and easy to do. It may not be an ideal solution i.e. replace and pray, but unless you've got someone very experienced with the challenges of Citroen suspension sitting in the car with you, confirming the drop links be an easy one to cross off the list... or not !!

[milleplod]

My droplinks have been done - the noise stayed exactly the same, under exactly the same driving conditions. Replacement might sort it on some cars, but it didn't on mine.

Pete

[EDC5]

In this thread I was advised it was the FRIP joints:
viewtopic.php?f=3&t=58511

But I've since had the wheel off (and strut) and there was no play in anything, I really did try to find the cause of the creak but nothing is obvious. As I said before I'm tempted just to replace the ARB especially seeing as they've been disturbed changing the strut.

Since failure of the hydractive suspension is rare I'm not sure if the clunk noise is a sign of anything being worn and it may just be characteristic.

It is a bit embarrassing when you've got passengers in the car who've had to put up with you waxing lyrical about the hydractive suspension only to hear a loud bang going over a minor speed bump

[Stickyfinger]

You don't drive fast enough.

Sticky, have you ever changed front struts on X7, or has there been leakage?

No

and yes I do (ever "jumped an X7 ? )

[Stickyfinger]

In this thread I was advised it was the FRIP joints:
viewtopic.php?f=3&t=58511

But I've since had the wheel off (and strut) and there was no play in anything, I really did try to find the cause of the creak but nothing is obvious.

Without using a large leaver bar you cannot tell if the FRIP joint is worn, it would be very hard to make the joint move even when worn with just hand pressure on the wheels.

[EDC5]

In this thread I was advised it was the FRIP joints:
viewtopic.php?f=3&t=58511

But I've since had the wheel off (and strut) and there was no play in anything, I really did try to find the cause of the creak but nothing is obvious.

Without using a large leaver bar you cannot tell if the FRIP joint is worn, it would be very hard to make the joint move even when worn with just hand pressure on the wheels.

Fair enough, I'll have to add FRIP joint to the list of things to replace then.



Looks like a good guide for replacing that and the ARB.

[Paul-R]

Just watched the video and I must say I'm not looking forward to having to replace the FRIP joint sitting on the ground. I just so miss the use of a four (or even two) post ramp. BTW I was particularly impressed by the levering device he had.

Actually seeing the suspension in action I am really struggling to understand why PSA have designed such a system. The separate FRIP joint and lower rubber bush decouple the steering movement from the suspension movement but I have to ask -why? What possible benefit is there over a simple bottom ball joint? Can anyone enlighten me?

[xantia_v6]

Actually seeing the suspension in action I am really struggling to understand why PSA have designed such a system. The separate FRIP joint and lower rubber bush decouple the steering movement from the suspension movement but I have to ask -why? What possible benefit is there over a simple bottom ball joint? Can anyone enlighten me?

With a ball joint, the pivot point of the suspension and the pivot point of the steering are forced to be coincident, the FRIP joint gives the designer freedom to optimise the geometry independently in 2 planes.

[xantia_v6]

The more I think about it, the more I am sure that the persistent problem with speed bumps is due to inappropriate (or at least marginal) damper settings in the corner spheres.

It may be possible to test the theory relatively easily by finding a car with the symptoms, and change the front spheres (at least temporarily) for some with softer rebound settings. The trick would be in identifying such spheres. Where does Sticky park his car? I actually suspect that HA3 (not HA3+) spheres would have the softer rebound damping required for this test.

[bobins]

Anyone know where I can get hold of one of the impact guns that he uses that automatically torque up the nuts, bolts and screws to their correct torque settings ?