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Old 23rd July 2019, 22:09   #1
T16
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Default Very specific front end clunk diagnosis

I am having some difficulty in diagnosing a front end clunk!
Here are the facts...

1) replaced lower tie mount as old one was split
2) Drivers side top mount makes a bit of a creaking at a specific angle coming off a driveway
3) Lower rear wishbone bushes look mint
4) Drop links are "new"
5) The sound ONLY happens when I am in 1st gear and I aggressively lift off the throttle and the front end pitch changes.
6) No big rattles over cobbles, bumps, potholes/general use.
7) ARB Bushes look fine

The top mounts are pretty corroded underneath, and for the life of me I cannot get any noise or movement to happen no matter how much force I put on the wheels with the car jacked and the wheels off the ground, in any direction, on any piece of the suspension.

It mainly seems to happen when the pitch of the car changes, rather than the yaw.

Sound familiar to anyone? I think my gut says topmount, and it loves a good creak when at a steep angle off the drive, but even perishing rubber in the mount shouldnt clunk so bad as its sandwiched between two large washers!

I remember previously on a previous car I had a front end rattle which happened over cobbles etc, and that was jsut a case of tightening up the lower arm to hub pinchbolt, this noise definitely seems different.
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Old 24th July 2019, 00:26   #2
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Lower Engine Mount maybe



Paul.
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Old 24th July 2019, 06:07   #3
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My cars use to make a clock on take off which progressed to a clonk feom 1st to 2nd and when putting in gear. It was the lower engine mount both times.
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Old 24th July 2019, 07:06   #4
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Quote:
Originally Posted by Dawn View Post
My cars use to make a clock on take off which progressed to a clonk feom 1st to 2nd and when putting in gear. It was the lower engine mount both times.
You mean the lower tie bar or a different engine mount like the hydramount?
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Old 24th July 2019, 07:36   #5
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Default Knocking noise when accelerating

I had this - it turned out to be an engine mount - try some silicone oil - lubricatation some times work!
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Old 24th July 2019, 07:54   #6
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Which mount? The way it sounds its like its the steering rack area.

Of course its almost impossible to tell inside the car.
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Old 24th July 2019, 09:41   #7
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First check for me would be to inspect the lower engine mount bushes and check fixings are not slack, classic symptoms. Hope that helps.
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Old 24th July 2019, 09:46   #8
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It sounds like a typical wishbone bush wearing clunk to me.

Get someone to look outside the car and see if the wheel is moving backwards or forwards when that happens.
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Old 24th July 2019, 10:00   #9
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Quote:
Originally Posted by hortonds View Post
It sounds like a typical wishbone bush wearing clunk to me.

Get someone to look outside the car and see if the wheel is moving backwards or forwards when that happens.
It could be lower wishbone bushes, but wear bad enough to cause a clonk would also cause a notable shift of geometry of the front end under heavy /sudden braking, ie whilst braking the car would tend to tramline or feel slightly unstable ( in my experience ).
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Old 24th July 2019, 12:56   #10
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Quote:
Originally Posted by T16 View Post
Which mount? The way it sounds its like its the steering rack area.

Of course its almost impossible to tell inside the car.
May find this thread useful.
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