Clunking on acceleration and braking..

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pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Clunking on acceleration and braking..

Post by pgunter66 »

Sorry if this has been covered before.. I have looked but not much found that can help.

Symptoms.

When pulling away in first I get a clunk sound which sounds like it is from the rear axle area.

On breaking I also get a clunk sound like something is stuck then frees itself.

I have ruled out the cv as it's not continuous, just annoying and does not seem right.

I have had the rear axle bushes replaced and a general check. The Independant BMW Bartley down in southampton want her back in so they can see what the issue might be. The prices quoted are scary lol..

The propshaft is £508.34 plus vat and five to seven days from Germany.
With the labour and vat comes to £750.00.

The differential is £1166.67 plus vat and five to seven days from Germany..
With the labour and vat comes to £1540.00.

We will need to check the noise from the rear end to find which one is at
fault.

So does anybody have any ideas ? Come across this before. ? Willing to meet up for a coffee and see what you think too..

Any help appreciated.
Brian4
Joined: Mon 19 Dec, 2011 19:02
Posts: 541

  Z3 roadster 3.0i
Location: Hinckley

Re: Clunking on acceleration and braking..

Post by Brian4 »

I thought the gearbox and axle were pretty bomb proof on these. One place to look is the centre bearing for the propshaft as these are prone or the rubber universal joint onto the diff as these can perish and start to break up.
Brian
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2000 E36/7 Z3 3.0i
2016 F31 335d
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lordhelpus
Joined: Sat 14 Sep, 2013 09:46
Posts: 128

  Z3 roadster 2.8
Location: Tax Exile

Re: Clunking on acceleration and braking..

Post by lordhelpus »

Hi, pgunter66

I would be looking at getting the rear up in the air on axle stands and would be looking at the rear pads/calipers/discs, and have the rear discs off and check the handbrake shoes for broken springs etc. Also check for bushes worn or missing on the rear shocks lower end and check upper mountings for security. also check exhaust mountings rubbers etc.

If not.........

Try this simple test

1.Apply the handbrake (pull on as much as possible) or even better wheelchock the front wheels.
2. Then start the car engage first gear/reverse gear and with the minimum of revs slowly lift and depress the clutch a number of times to see if you can recreate the noise.

if you get the noise by doing this test then I would suspect you have play (wear) in the rear transmission\propshaft.

you can pick up a rear diff on ebay for about £120 -£170.

If I was more local I would have accepted your kind offer of a coffee!
1997 2.8................ Montreal Blue
Chiefy
Joined: Tue 30 Oct, 2012 09:42
Posts: 45

  blank

Re: Clunking on acceleration and braking..

Post by Chiefy »

Have a good look at the differential rear mount flexi to boot floor and possibly boot floor itself.
pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Re: Clunking on acceleration and braking..

Post by pgunter66 »

Checked the boot floor and the welds. All good.

I think it's is either the brake pads or the rear shaft linkage somewhere. Have not worked on a car since my old Mk IV ford Zodiac days. So plenty of fun ahead.

All thoughts gratefully received.
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: Clunking on acceleration and braking..

Post by BonBon »

As Cheify said....look at the rubber differential mount - not the floor welds
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Clunking on acceleration and braking..

Post by Southernboy »

........ while you're under there. have a close look at the prop shaft center bearing and it's mounting as well as the gearbox mounting. It may also be an exhaust mounting which has broken or come unhitched. Also check for broken rear suspension spring(s). And finally, there are 2 large weighted objects housed in the left & right corners of the rear bumper which can detach and have been known to be the source of thumps.
"Normal is overrated"
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Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: Clunking on acceleration and braking..

Post by Mike Fishwick »

Check the pivoting weights inside the ends of the aluminium bumper bar - these are supposed to make the car feel more rigid, but I don't see how!

The have rubber pads to limit movement, and it is not unknown for the to fall off, making a clunk as you described. IF so, use impact adhesive to stick a rubber tap washer ontothe weight - although dealers have been known to wrap the weight in bubble wrap!
A Z3 is not just for Christmas - it's for life!
Flight
Joined: Mon 16 Sep, 2013 20:43
Posts: 97

  blank

Re: Clunking on acceleration and braking..

Post by Flight »

Hi all.
I also have this problem, but in my case I think there's to much backlash between crown wheel and pinion. Probably compounded by a little play in the drive shafts. when turning the prop shaft by hand it really feels excessive. I consider the drive shaft play to be normal, and would like to concentrate on the Crown wheel & Pinion. As the car has only covered 35000 miles, I suspect this problem to be a manufacturing glitch.
Does any one have any information regarding the set up of this arrangement? I know some diffs can have a shim adjustment to regulate backlash.
Thank you Flight
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Clunking on acceleration and braking..

Post by Southernboy »

That movement is "standard" on these cars... No matter your mileage. It's been an issue many have complained about... The rotational play in the drive shaft seems excessive, and there's not much to be done about it, short of having the diff re-engineered with less tolerant parts. If you find a "reasonable" solution to getting the crown 7 Pinion to fit even somewhat more snugly, I would be interested to hear of the solution... :wink:
"Normal is overrated"
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pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Re: Clunking on acceleration and braking..

Post by pgunter66 »

Thank you for the pointers. I have had one email via an old friend who thinks it might be the guibo rubber mount as the car is a 1999 and has never had a great deal of use. So might be the rubber has started to soften since I have done more miles in three months than its done in two years.. If I get them to have a look at this and might even replace the shaft bearing at the same time.

I will let you all know after its day in the garage on the 31st. In the mean time, it would be good to know if anybody else has had the guibo replaced and if it made a difference.
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Clunking on acceleration and braking..

Post by Southernboy »

They are pretty tough with metal sleeves for the 6 bolts that pass through, so not frequently an issue. They will tend to crack vs soften.
"Normal is overrated"
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pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Re: Clunking on acceleration and braking..

Post by pgunter66 »

Ok, she's back from Bartley BMW. Dermot the main guy / owner is puzzled as well about the 'clunk'.

Brakes check.
Handbrake checked.
Propshaft checked.
Guibo checked.
Gearbox checked.
Driveshaft checked.

Slowing down any gear.. Apply break with clutch to the floor.. Almost to a stop.. Clunk..
Slowing down any gear... Clutch still engaged... Almost to a stop.. Clunk..
Accelerating between gears 1st & 2nd... Clunk..
Bracket and welds checked.. All ok.

Most annoying... But it's got to be something... Any thoughts by anybody ?
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Mint
Joined: Tue 01 Nov, 2011 18:43
Posts: 475

  blank

Re: Clunking on acceleration and braking..

Post by Mint »

As mentioned above - what about the weights in the bumper - did they check those?
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Clunking on acceleration and braking..

Post by Southernboy »

The question is... what are you describing by the term "clunk"... is it a hard metallic sound, a dull thump, or the sound of something bumping the under body.... it's very difficult to reply to "clunk" without guessing at all the possible options. Perhaps you could try to be more precise in the description of the sound, and also try to indicate where you sense it is coming from...ie. right / left rear or front etc... it could be a can of baked beans under the passenger seat for all we can guess... :D
"Normal is overrated"
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pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Re: Clunking on acceleration and braking..

Post by pgunter66 »

It's not a can or the weights lol..

It's like something is stopping or coming to a stop against a metal object. I first thought it was a sticking brake pad .. Then the clunk as it releases. If that makes sense. I hope to be meeting up with a few z3 owners at some point.. Might even have a better idea than me..
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: Clunking on acceleration and braking..

Post by BonBon »

These two are pretty standard so I did not even list them-
On a lift:
1. Check the rubber exhaust mounts and support welds
2. Check there is no rattle on either sides of the petrol tank due to softening of the foam above the support straps
3. It can also be the engine mounts that is reflected by a knock in the rear by movement of the exhaust.
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lordhelpus
Joined: Sat 14 Sep, 2013 09:46
Posts: 128

  Z3 roadster 2.8
Location: Tax Exile

Re: Clunking on acceleration and braking..

Post by lordhelpus »

Hi, pgunter66
Where would you say this noise is coming from?....

1. front\rear of the car?
2. does it happen over bumps?
3. Is the noise inside the car?
4. outside the car \ underneath?
5. Roof up \ roof down?

Have you tried Rocking the car to see if you can get the noise????

to be honest with you it could be a hundred things from a broken front strut!... to a seat bush!. :shrug

If you can't find it then just wait..... and it (whatever it is) will break eventually......... and show itself.
anyway look at it this way "it's not a fault... it's a characteristic" of your vehicle.............. for what it's worth my money is on the rear diff.

Good luck ......let us know how you get on.
1997 2.8................ Montreal Blue
pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Clunking on acceleration and braking..

Post by pgunter66 »

Update...

Just replaced the rear bushes on the ARB.. Still clunks... Lol...

This only happens on acceleration from a start.. And when you are nearly at a stop after applying the brakes. It's from the rear. Hence replacement of bushes .. Area by area...

One thing I will be doing over the colder months is a complete strip down of the rear brakes and hand brake area. We shall see what is revealed.
rambo
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Joined: Tue 16 Aug, 2011 17:17
Posts: 83

  Z3 roadster 2.0
Location: Grimsby

Re: Clunking on acceleration and braking..

Post by rambo »

Sounds daft but I had half my 1966 MGB in bits with the same problem, took my pal out to demo and he found a U2 battery rolling around under the passenger seat.
Mind you there was no carpet under the seat!!
Best of luck.
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lightning
Joined: Tue 27 Nov, 2007 08:15
Posts: 818

  Z3 roadster 3.0i
Location: Stockport

Re: Clunking on acceleration and braking..

Post by lightning »

If there turns out to be play in the diff, you don't HAVE to change it.

It will probably go on for years like that. Have you checked the bracket that holds it to the boot floor? This can be repaired for about £300.
pgunter66
Joined: Sat 05 Jul, 2014 20:53
Posts: 28

  Z3 roadster 2.2i
Location: Colden Common, Winchester, Hampshire, UK

Re: Clunking on acceleration and braking..

Post by pgunter66 »

Thanks lightning.

I have had a preliminary look at the bracket and all seems good. If it's a play in diff, I will be living with it... But will be looking at a replacement in the coming years as I intend to keep my little Z on the road.
Flight
Joined: Mon 16 Sep, 2013 20:43
Posts: 97

  blank

Re: Clunking on acceleration and braking..

Post by Flight »

Just been looking at the Z4 forum, and couldn't see any reference to the clunking or knocking which is apparent on most Z3s. What is the difference? what has changed? are any parts common to both or is the Z4 completely different? ie gearbox differential etc.
Cheers
Flight
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