Author Topic: Klonk  (Read 4922 times)

Alf

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Klonk
« on: May 30, 2013, 07:33:00 »
Starting to notice an audible 'klonk' when the powertrain takes up drive from rest that I'm sure wasn't there before. Seems a little louder if i wind on a bit of steering lock as i pull away. Strange thing is sometimes it sounds like its coming from near the auto 'box and sometimes further back near the axle. Taking it to the mechanic tomorrow, but any ideas?
Alf
'69 280SL. Silver (180 G) with black hardtop

WRe

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Klonk from rear axle rubber mount
« Reply #1 on: May 30, 2013, 08:36:10 »
Hi,
A typical Klonk comes from the rear axle rubber mount.
Test: Accelerate hard, stop acceleration immediately, if there is a Klonk it's from there.
...WRe
« Last Edit: May 30, 2013, 11:05:06 by WRe »

mbzse

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Re: Klonk from rear axle rubber mount
« Reply #2 on: May 30, 2013, 10:34:13 »
Quote from: WRe
A typical Klonk comes from the rear axle rubber mount

To further illustrate what WRe means, look at 1:58 into the video in this Forum posting:
http://www.sl113.org/forums/index.php?topic=17887.msg124672#msg124672

/Hans in Sweden
.
/Hans S

Alf

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Re: Klonk
« Reply #3 on: May 31, 2013, 07:48:20 »
Thanks for the replies. I tried the accelerate /decelerate test but no klonk. I get my klonk when the weight gets transferred suddenly to the back. Ev: when launching from rest
Alf
'69 280SL. Silver (180 G) with black hardtop

Larry & Norma

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Re: Klonk
« Reply #4 on: May 31, 2013, 08:16:54 »
Could it be the flexi disc on the prop shaft?
Larry Hall (Gnuface)
2023 Ioniq6
2005 C230
1970 280SL

WRe

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Re: Klonk
« Reply #5 on: May 31, 2013, 09:33:13 »
Hi,
nevertheless I would check the rear axle rubber mount, it's quite easy, see here http://www.beetle.homepage.t-online.de/Gummilager%20Hinterachse%20Pagode%20MB%20W113.htm.
If you support the rear axle you can remove this mounting in the trunk.
....WRe

ja17

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Re: Klonk
« Reply #6 on: May 31, 2013, 13:59:03 »
Yes the rear trunk mount is a good possibility.  Also check the mounting points of the two trailing arms on each side of the car where they attach to the chassis.  When the rubber mount goes bad a clunk noise can start happening. If this is the case you will see signs of metal to metal contact between the end of the trailing arm and the "cup shaped" support bracket.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
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Alf

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Re: Klonk
« Reply #7 on: May 31, 2013, 16:49:34 »
OK. Just back from the mechanics and if course tbd car refused to 'Klonk' on demand. Anyway, checked all the mountings and all OK. BUT the flexi disc was missing 2 bolts. These have now been replaced and so far so good. So Larry, you could have nailed it. Fingers crossed. Once again thanks for all the suggestions
Alf
'69 280SL. Silver (180 G) with black hardtop

stickandrudderman

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Re: Klonk
« Reply #8 on: May 31, 2013, 17:01:39 »
With two missing bolts from the flex disc you would certainly have had a vibration at speed.