Irritating knocking taking the edge off enjoyment

[hut49]

A number of short runs in the 450 ('99 13,000 miles) over local roads over the past 10 days have raised my awareness of a persistent and intrusive knocking from the back of the car. It's not there at higher speeds when the suspension is under greater load but at lower speeds on uneven surfaces it's a constant knock-knock-knock. I reckon that each short journey requires a 30 mile thrash on fast roads to remind me why I'm driving a Chimaera and not a modern day car!

300 miles ago I had a full TVR service and asked for this to be rectified and the 2 rear bilstein shockers were identified as the culprits and were replaced by AVO adjustables. It seemed better for a while but now we are back to pre-service knock levels!

I've checked that there's nothing obviously lose in or around the boot, and the rear exhaust mounting is new and tight. The ARB and mountings are OK.

I know that Chimaera's are reknown for noises 'arft and I've got the car booked back in again for the problem to be diagnosed and rectified. But has anyone been through this and can tell me what is likely to be the problem?

[mark c]

My shocks have noisy valves - or so I was told during a service... Makes an irritating knocking sound over rough roads when cold. Don't think it's anything to worry about... I asked about changing them and they said the new ones could very well have the same problem.

Regards,

Mark

Edited because I can't read!

>> Edited by mark c on Tuesday 10th June 10:30

>> Edited by mark c on Tuesday 10th June 10:31

[hut49]

Not sure I understand how shocker valves make a knocking sound - any wisdom out there?

[dannyboyo]

Does it relate to acceleration/decelleration or going over bumps? Is it in any gear?

Clunking on my car turned out to by a worn UJ. Could be a loose diff to, or driveshafts i guess.

[GAZ_3884]

What you describe seems exactly the same as what my car suffers from... I took it to Offords and guess what they said..........

They all do that sir!!!

Seems the suspension needs to 'warm up' and the knocking from the rear is very common while cold. Sure enough, after 10 or 20 miles it fades away every time.

I have no idea of the technicalities of it, but in a TVR kinda way (ie parallel universe common-sense) it works. Hope yours is the same and not a more expensive problem!

[GreenV8S]

hut49 said: Not sure I understand how shocker valves make a knocking sound - any wisdom out there?

Probably caused by air locks in the damper making a knocking noise as they go through the valves, nothing to be particularly worried about I would have thought as long as you know the dampers are damping OK.

[hut49]

dannyboyo said: Does it relate to acceleration/decelleration or going over bumps? Is it in any gear?

No, the knocking (not a drivetrain clunking like a slack diff) is there all the time around 20-40mph, all gears and even coasting in neutral. Though as Gaz said, after the suspension has warmed through, it's less, as it is at higher speeds. It seems to be caused by short, undamped oscillation of the hub - nearside I think. This leads me to suspect one or more of the hub bushes.

[JonRB]

You haven't locked the wife / girlfriend in the boot by any chance? Causes an awful noise as they pound on the bulkhead pleading to be let out.

Seriously, does the noise occur at full suspension travel? Could you be hitting the bump stops?
The oil-filled dampers on my Corrado thump the bump stops on the rear quite regularly, especially when it is cold.

EDIT: Sorry, having read your previous posts more carefully I can see that it is unlikely to be the bump stops given the circumstances under which the noise occurs.

>> Edited by JonRB on Wednesday 11th June 12:56

[hut49]

One month on and still no AVOs or Bilsteins available - what the hell's going on?

[marco]

Hi

I've had a similar thing on my griff and it turned out to be the brake pads rattling in the calipers.

Does the sound stop if you pull on the handbrake whilst moving?

If so then you can take them out, clean and grease them but it makes more sense to just get some new ones at the same time.

Or it might be something else . . .


Marco

[iandbeech]

GAZ_3884 said:

What you describe seems exactly the same as what my car suffers from... I took it to Offords and guess what they said.......... They all do that sir!!! Seems the suspension needs to 'warm up' and the knocking from the rear is very common while cold. Sure enough, after 10 or 20 miles it fades away every time. I have no idea of the technicalities of it, but in a TVR kinda way (ie parallel universe common-sense) it works. Hope yours is the same and not a more expensive problem!

Didn`t you say goodbye a while back?! Couldn`t keep away then?!