ChristopherEmmanuel
Posts: 39
Joined: Mon Aug 21, 2017 10:02 am

Clunking noise when going over bumps

Wed Nov 22, 2017 6:02 am

Hi all, sorry for the long waffle ...................
But I hope this will help others as the dealers really do not have a clue. I purchased my i3 back in August 2017 and when test driving noticed a clunking noise from the nearside suspension, dealer said he would sort out before delivery.

Well several visits to the dealer resulted in them not fixing the problem and throwing many new parts to rectify the issue and they did not succeed.
After my own investigation i found that the steering column shaft was loose and the dealer fitted a new column, clunking still present the second dealer then had it in four more times to rectify the problem and could not, then told me they all do that?

I went to a third dealer who threw all new suspension parts on again in case of faulty new parts and still no joy.

I being really pissed at this stage had a look myself and found the front sub-frame bolts at least 1.5 turns loose. I tightened them up and guess what, The clunking noise stopped!

I went to the third dealership to see if the bolts were stretch bolts and they are. BMW recommends 104Nm torque setting but at this setting it still clunks a bit.

The tech told me that the 104Nm is because the bolts screw into the carbon fiber tub, but looking at the drive module chassis, it bolts directly to this so do not understand why such low torque settings.

I hope this will help someone who has this problem as it seems to be a limited problem with others I have spoke to who have a clunking noise on their car.

theothertom
Posts: 364
Joined: Mon Mar 20, 2017 6:08 am
Location: South Carolina

Re: Clunking noise when going over bumps

Wed Nov 22, 2017 7:05 am

Thanks for tracking this down and posting.

jadnashuanh
Posts: 5036
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Clunking noise when going over bumps

Wed Nov 22, 2017 9:38 am

FWIW, that's the same spec for tightening the wheels. Aluminum is probably the limiting factor. The ultimate strength can be overcome somewhat by using a larger diameter and/or longer fastener so there's more area. Overstressing could cause the aluminum threads to be damaged.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV
Soon (hopefully!) A 2021 X5 45e will replace the above

ChristopherEmmanuel
Posts: 39
Joined: Mon Aug 21, 2017 10:02 am

Re: Clunking noise when going over bumps

Wed Nov 22, 2017 2:47 pm

your welcome, and agreed, not really room for a large washer, wish there was. I am also going to check the shock absorber bolts tomorrow as I am sure these will not be tight enough also. Will post my findings as soon as I can

ChristopherEmmanuel
Posts: 39
Joined: Mon Aug 21, 2017 10:02 am

Re: Clunking noise when going over bumps

Sat Nov 25, 2017 9:51 am

Well BMW had the car in to change the bolts on the subframe as some of them were not where they are supposed to be (oops maybe i tightened them to much) and they said they had torqued them to 104Nm.

in the mornings when setting off when car was cold the clunking started again but almost went away when driving for a while.

I was not satisfied with this and was sure the bolts needed to be tighter.Mmmmmm

OK I decided that the problem had to be with the sway bar as the clunking was drop link clunking.

I found the sway bar was solid in the bushings and would not move up or down. Nailed it!

The sway bar could not move up or down with the shocks and was acting as a big torsion spring, I am surprised the drop links did not snap under the stress.

Sprayed WD40 on the bar in the bushes and the noise has disappeared completely even when cold. BMW do not sell bar separately so £200 for the privilege. No Poly bushes from Powerflex either?

So there you have it. Clunking may not be drop links check sway bar bushes first. Three dealers have thrown thousands of pounds of parts and labor and all it needed is a bit of lubrication.

Hope this helps a lot of people with this new and innovative car and the new problems we all have yet to encounter :D

theothertom
Posts: 364
Joined: Mon Mar 20, 2017 6:08 am
Location: South Carolina

Re: Clunking noise when going over bumps

Sat Nov 25, 2017 1:39 pm

In the US we have a saying for your determination....bird dogging. A bird dog focuses on the matter at hand and cannot be swayed one way or the other until the task is complete. Thanks for "bird dogging" this one!

Toalmar
Posts: 17
Joined: Sat Nov 25, 2017 3:50 pm
Location: Norway

Re: Clunking noise when going over bumps

Sat Nov 25, 2017 4:01 pm

Very good that somebody did sort this out. I've got this clunking issue since February this year. My dealer has tried every think. when they changed the shock absorber and the guide support on top of the shock absorbers the noise was gone, but just for about 1500 km.
I had my car to the dealer last no on Friday and they told it was nothing more to do. I've been looking around for this issue long time, and I'm happy to find somebody that probably sort out the problem. Please make some pictures of the bolts very you did the modification it's easier to find them then. I'm not sure what you mean with Subframe bolts since I'm from Norway and we use different names.

ChristopherEmmanuel
Posts: 39
Joined: Mon Aug 21, 2017 10:02 am

Re: Clunking noise when going over bumps

Mon Nov 27, 2017 12:01 pm

Hi Toalmar



http://www.realoem.com/bmw/enUS/showpar ... Id=31_1051


item number 2

Also check first sway bar bushes as mine were seized and would not let the bar move with the drop links,
Last edited by ChristopherEmmanuel on Mon Dec 04, 2017 5:16 am, edited 1 time in total.

Toalmar
Posts: 17
Joined: Sat Nov 25, 2017 3:50 pm
Location: Norway

Re: Clunking noise when going over bumps

Sun Dec 03, 2017 1:19 pm

When I check this little bit more I find out that the Subframe is mounted with 6 bolts, 2 in front M12 x 98mm), 2 in middle (M12 x 60mm) and 2 in rear (M12 x 98mm).
The torque for these bolts is a little different. Middle and rear 104Nm, front bolts 96Nm and then 90° rotation if I understand the document from BMW right
Last picture of this page show the bolts:
https://www.newtis.info/tisv2/a/en/i01- ... 1VnXrmLD63

On this page you see the torque for the bolts at the subframe:
https://www.newtis.info/tisv2/a/en/i01- ... 1VnXqb7ZMd

ChristopherEmmanuel
Posts: 39
Joined: Mon Aug 21, 2017 10:02 am

Re: Clunking noise when going over bumps

Mon Dec 04, 2017 5:15 am

Thanks for that,

Yes mine were very loose, and were tightened to the right torque by the dealer. I have had a fairly quiet car for a couple of weeks now since lubricating the sway bar bushes, but the odd heavy knocking when going over big pot holes. am hoping the dealer will replace the sway bar bushes to completely eliminate the knocking noise.

Return to “Problems / Troubleshooting”