C5 HDI Front suspension top mounting.

[johnsumner]

HI,
I have a 2006 C5 2.0 HDI VTR and have been plagued with a rumbling knocking sound mainly from the front offside of the car. I have changed the engine mounting anti torque bar which was worn, but the noise persists. You only here it on poor road surfaces, on smooth tarmac its silent. No knocks etc when going over speed bumps. It's not tyre noise. I have removed the under engine cover and plastic panels associated with it also the engine cover.
Could it be the suspension upper mounts and if so are there any clues as to verifying the bearing or rubber mount is failing, one thing that leans me in that direction is the fact that some days the steering feels light than on other days.
The unit is sold as complete unit as I understand it and costs around £150 so it's not just a bearing change.
Any pointers would be helpful.

Thanks

John.

[Mandrake]

Hydractive C5's don't have a bearing in the strut top like a normal coil spring suspension car - the strut top is basically just a big flexible rubber mount that allows a few degrees of tilt but no rotation. The "top" pivot is provided by the strut ram unit rotating around the stationary strut shaft which in turn is bolted into the strut top, and it's extremely unlikely for this to be causing a knock.

Does the noise still occur with the brakes lightly applied while travelling over broken surfaces ? Does it happen more often when you're turning on a tight corner than straight ahead ?

I assume obvious candidates like droplinks, lower ball joint and steering joints have been ruled out ?

[johnsumner]

Hi Simon,
I think I can cross the top mount off the list.
Drop links have been done (with Citroen drop links) I have also fitted new discs and pads both Citroen parts and its just passed it test. I did also ask them to check the engine mounts, nothing found. I have had the car for 3 years now and I have been unable to locate the noise.I am going to have a look behind the wheel arch covers to see if anything is loose.
A while ago I had the bumper off and did not notice the Bumper absorber assembly which is padding between the plastic bumper and the metal bumper behind it.
I know the car must have had a light shunt as I had to make a couple of brakes for the headlights as two of the plastic brackets were broken so perhaps that's another check to be done. Thanks John.