Knocking sound from rear of car

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evoke
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Knocking sound from rear of car

Post by evoke » 23 Apr 2013, 13:01

I'm trying to trace the source of a knocking sound that I sometimes get when I drive on a rough road or go around a corner. The car has been checked by a Citroen dealer and an independent workshop who changed some bits on the front suspension/steering to eliminate a knocking sound from the front of the car.

So, assuming that the rear suspension components are okay, where else could that knocking sound be coming from? Maybe the rear seats aren't locked down properly? Or maybe the rear suspension components need to be checked again?

411514
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Re: Knocking sound from rear of car

Post by 411514 » 23 Apr 2013, 13:06

First place to check is probably spare wheel well, look for unsecured jack or loose wheel nut, then exhaust backbox heat shield.

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Mandrake
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Re: Knocking sound from rear of car

Post by Mandrake » 23 Apr 2013, 13:37

Check the rear seat back rests are clicked in to the latch at the top, I've fallen for that a few times myself... :)

Other than that or the spare wheel/jack it could be the exhaust touching on the body somewhere as the exhaust flexes on its mountings, particularly around the rear muffler area.

If you have a rubber mallet try banging on the exhaust, suspension chassis and body under the rear, that can sometimes provoke a noise like that without having to drive the car, making it much easier to find.

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Xaccers
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Re: Knocking sound from rear of car

Post by Xaccers » 23 Apr 2013, 14:19

You've not left the mother in law in the boot again have you?

evoke
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Re: Knocking sound from rear of car

Post by evoke » 23 Apr 2013, 15:41

Thanks for all the suggestions, guys. I'll go through them one by one.

However, I may have found the issue. I, too, thought that rear seat backs might not be latched properly. I actually started reading the owner's manual and noticed that the seat bench (rear seat bases) can also be lifted out to create a much longer boot load area. I tried lifting up each seat squab and it required no effort at all. I played around with the seat bases and found that they do clip into place. It's not a strong latching mechanism but enough to stop them rattling.

I'll drive the car a bit more to see if this has fixed the issue but the rear seat squabs were definitely loose.

boristhespie
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Re: Knocking sound from rear of car

Post by boristhespie » 23 Apr 2013, 23:38

Maybe rear trailing arm bearing if not?

I was told sound could travel. Also very hard to diagnose.
Last edited by boristhespie on 27 Apr 2013, 23:39, edited 1 time in total.

evoke
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Re: Knocking sound from rear of car

Post by evoke » 24 Apr 2013, 10:46

So far so good. I'll need a few more drives to be 100% sure.

evoke
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Re: Knocking sound from rear of car

Post by evoke » 25 Apr 2013, 12:02

Hmm...just went out to try out my new extending wheel brace and found that the locking wheel nuts on two of the wheels were loose, so i've tightened them up. I don't think they were loose enough to cause an issue. Still, not good.

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Mandrake
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Re: Knocking sound from rear of car

Post by Mandrake » 25 Apr 2013, 14:35

Loose wheel bolts can cause a clicking sound particularly when cornering slightly. Either way its good you found them and tightened them. :shock: