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Annoying rear knocking noise. E86

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Antonyt94
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Annoying rear knocking noise. E86

Post by Antonyt94 » Thu Jan 05, 2023 7:28 pm

Hi all, I have had a very annoying knocking noise coming from the rear of my coupe for months and can't pin point it. At first I thought it was my exhaust heat sheild because it was loose but I had this secured and the noise remains...

From reading other posts it could well be the rear top mounts? Just wondering if anything else could be causing the issue from anyone else's experience.

07 E86 Si Sport.

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enuff_zed
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Annoying rear knocking noise. E86

Post by enuff_zed » Thu Jan 05, 2023 7:40 pm

Do you have any receipts for rear suspension work? If they are Meyle HD top mounts they will be the culprit.
Fitted them on the wife's car and they knocked like mad.
I removed them and discovered that the metal sleeve in the middle is able to fit right up to the cup washers, with no gap. The wear after less than 1500 miles was shocking and of course metal on metal is never good.
I went back to Lemforder and everything is peaceful again.
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Annoying rear knocking noise. E86

Post by bigwinn » Thu Jan 05, 2023 7:44 pm

I advise you to look at the clearance on the anti roll bar and the mounts it sits on

Especially if you have had bushes/drop links done
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Antonyt94
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Annoying rear knocking noise. E86

Post by Antonyt94 » Thu Jan 05, 2023 10:28 pm

bigwinn wrote: ↑Thu Jan 05, 2023 7:44 pm I advise you to look at the clearance on the anti roll bar and the mounts it sits on

Especially if you have had bushes/drop links done
Hi, I do believe that the bushes were changed to poly ones by one of the prev owners... I'm not too great at DIY mechanics, would this be an easy task?

Thanks for the reply btw.

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Annoying rear knocking noise. E86

Post by enuff_zed » Thu Jan 05, 2023 10:38 pm

Antonyt94 wrote: ↑Thu Jan 05, 2023 10:28 pm
bigwinn wrote: ↑Thu Jan 05, 2023 7:44 pm I advise you to look at the clearance on the anti roll bar and the mounts it sits on

Especially if you have had bushes/drop links done
Hi, I do believe that the bushes were changed to poly ones by one of the prev owners... I'm not too great at DIY mechanics, would this be an easy task?

Thanks for the reply btw.
Very easy. Start the car, point it towards Lincoln and look for Bigwinn 🀣
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Annoying rear knocking noise. E86

Post by bigwinn » Thu Jan 05, 2023 10:51 pm

enuff_zed wrote: ↑Thu Jan 05, 2023 10:38 pm
Antonyt94 wrote: ↑Thu Jan 05, 2023 10:28 pm
bigwinn wrote: ↑Thu Jan 05, 2023 7:44 pm I advise you to look at the clearance on the anti roll bar and the mounts it sits on

Especially if you have had bushes/drop links done
Hi, I do believe that the bushes were changed to poly ones by one of the prev owners... I'm not too great at DIY mechanics, would this be an easy task?

Thanks for the reply btw.
Very easy. Start the car, point it towards Lincoln and look for Bigwinn 🀣
:rofl:

It’s a fairly easy job with the tools and knowledge- it’s a case of slackening the retaining bolts then moving the bar sideways to prevent the fouling on the metalwork

But as Martin says happy to help if I can
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Antonyt94
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Annoying rear knocking noise. E86

Post by Antonyt94 » Fri Jan 06, 2023 10:46 am

enuff_zed wrote: ↑Thu Jan 05, 2023 7:40 pm Do you have any receipts for rear suspension work? If they are Meyle HD top mounts they will be the culprit.
Fitted them on the wife's car and they knocked like mad.
I removed them and discovered that the metal sleeve in the middle is able to fit right up to the cup washers, with no gap. The wear after less than 1500 miles was shocking and of course metal on metal is never good.
I went back to Lemforder and everything is peaceful again.
Hi, tbh I'm not too sure, I'll have a rout through some paperwork and see if I can find anything. Iv had the car a year and a half now and there's quite a bit of paperwork. Is it just a case of swapping them out and placing the lemforder ones in then from the boot? Or is it a full shock removal job?

Thanks for reply.

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Annoying rear knocking noise. E86

Post by enuff_zed » Fri Jan 06, 2023 10:49 am

Antonyt94 wrote: ↑Fri Jan 06, 2023 10:46 am
enuff_zed wrote: ↑Thu Jan 05, 2023 7:40 pm Do you have any receipts for rear suspension work? If they are Meyle HD top mounts they will be the culprit.
Fitted them on the wife's car and they knocked like mad.
I removed them and discovered that the metal sleeve in the middle is able to fit right up to the cup washers, with no gap. The wear after less than 1500 miles was shocking and of course metal on metal is never good.
I went back to Lemforder and everything is peaceful again.
Hi, tbh I'm not too sure, I'll have a rout through some paperwork and see if I can find anything. Iv had the car a year and a half now and there's quite a bit of paperwork. Is it just a case of swapping them out and placing the lemforder ones in then from the boot? Or is it a full shock removal job?

Thanks for reply.
Shock removal. And I believe it's a bit more difficult to access the mounting bolts in the boot of an E86.
Possibly check out Stuart's suggestion first.
HQ of 'Norfolk Zed Rescue'.
Always happy to help if I can.

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Secondtothird
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Annoying rear knocking noise. E86

Post by Secondtothird » Fri Jan 06, 2023 11:55 am

When does it knock? If it's more noticeable at low speeds over broken roads, it definitely sounds like rear top mounts. I had this last year, went to Lemforder, all is well in the world again.

Owen

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Annoying rear knocking noise. E86

Post by Antonyt94 » Fri Jan 06, 2023 2:56 pm

Secondtothird wrote: ↑Fri Jan 06, 2023 11:55 am When does it knock? If it's more noticeable at low speeds over broken roads, it definitely sounds like rear top mounts. I had this last year, went to Lemforder, all is well in the world again.

Owen
Yes, very noticeable at lower speeds (10-30 mph on most surfaces. From watching some YouTube vids I am thinking it's the top mounts due to the noise sounding very familiar.

Where did you take your to have the problem fixed?

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Annoying rear knocking noise. E86

Post by Antonyt94 » Fri Jan 06, 2023 2:56 pm

Antonyt94 wrote: ↑Fri Jan 06, 2023 2:56 pm
Secondtothird wrote: ↑Fri Jan 06, 2023 11:55 am When does it knock? If it's more noticeable at low speeds over broken roads, it definitely sounds like rear top mounts. I had this last year, went to Lemforder, all is well in the world again.

Owen
Yes, very noticeable at lower speeds (10-30) mph on most surfaces. From watching some YouTube vids I am thinking it's the top mounts due to the noise sounding very familiar.

Where did you take yours to have the problem fixed?

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Annoying rear knocking noise. E86

Post by Secondtothird » Fri Jan 06, 2023 3:16 pm

Hello

I took mine to Autoworks, the BMW specialist, near Swindon. I'm sure any garage competent in taking all the rear plastics apart to get to the rear strut tops could do it though.

Definitely rear top mounts though, get some Lemforder ones, they're not too bad price wise and very good quality.

Owen

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Annoying rear knocking noise. E86

Post by Antonyt94 » Sat Jan 07, 2023 4:14 pm

Secondtothird wrote: ↑Fri Jan 06, 2023 3:16 pm Hello

I took mine to Autoworks, the BMW specialist, near Swindon. I'm sure any garage competent in taking all the rear plastics apart to get to the rear strut tops could do it though.

Definitely rear top mounts though, get some Lemforder ones, they're not too bad price wise and very good quality.

Owen
Ahh right ok, I'm up in Wigan. I'll take it to my local zed man and have him fit the new lemforder mounts I bought see if it fixes the problem.

Cheers for the reply.

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Annoying rear knocking noise. E86

Post by Secondtothird » Sat Jan 07, 2023 8:27 pm

No probs at all, best of luck.

Owen

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