Slight clonk from back of car

Technical advice Q&A

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Robbiee
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Location: Derbyshire

#1 Slight clonk from back of car

Post by Robbiee » Fri Jul 05, 2019 11:03 am

Hi all
I get a slight clonk/knock when clutch engaged and drive is going to prop shaft pulling away in 1st and occasionally when I engage second I also get it.
It seems to happen when I stop and engage reverse too
It appears to be from the rear of the car
No clutch slip, gears engage easily, car drives well, no wobbles, prop shaft rear bolts to diff all tight, no rear brake noise, drive shafts bolted tight, wheels firmly knocked on
Any ideas??
Robbie
Robbie 1962 3.8 Coupe OSG 1962 OTS ODG

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politeperson
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#2 Re: Slight clonk from back of car

Post by politeperson » Fri Jul 05, 2019 11:09 am

Radius arm bushes(on the cups).

Pretty easy to do. The new cheap ones are crap!.

James
Its true, but Enzo never said it
Too many E types
XK120 SUs

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Robbiee
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Location: Derbyshire

#3 Re: Slight clonk from back of car

Post by Robbiee » Fri Jul 05, 2019 11:12 am

Interesting
I’ll check
The off side(right) just behind me has certainly been a little clonky since fitting!
Robbie
Robbie 1962 3.8 Coupe OSG 1962 OTS ODG

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Moeregaard
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#4 Re: Slight clonk from back of car

Post by Moeregaard » Fri Jul 05, 2019 4:41 pm

As James mentioned, it's probably radius-arm bushings, but I would raise the rear of the car and look, wiggle and poke at everything. I once experienced some intermittent clunking in the rear of my '65, and it turned out to be a half-shaft U-joint bearing breaking up. I would have expected more drama from this, but it was just the occasional clunk.
Mark (Moe) Shipley
Former owner '66FHC, #1E32208
Former owner '65FHC, #1E30036

Planning on getting E-Type No. 3 as soon as possible....

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Robbiee
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Location: Derbyshire

#5 Re: Slight clonk from back of car

Post by Robbiee » Fri Jul 05, 2019 5:42 pm

Hi Moe
Thanks
I’ll have a good wiggle
It does sound a bit more like some slack is being taken up when I pull away from stationary either in forward or reverse
Robbie
Robbie 1962 3.8 Coupe OSG 1962 OTS ODG

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madjack4
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#6 Re: Slight clonk from back of car

Post by madjack4 » Sat Jul 06, 2019 9:22 pm

Hi i had the same problem it ended up being one of the driveshaft UJs no play could be found but when i dismantled the shafts i found the right hand inner joint had one cup that had collapsed no play could be felt on shaft when on the bench i had decided to replace them even though they were new when i bought the car 5 years ago
Regards Rob
Rob 1972 s3 roadster
Aston Martin DB9 Volante

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