T1N suspension knocking sound

vzapor

New member
Hi,
I have a knocking/ clunking sound I need to identify. Sound file attached.
Recording was taken with carpet removed , close to the strut nut on the driver's side.
The speed was 20-25 m/h. There is no such sound when going over speed bumps. Strut bounces one time back, without any sounds or leaks outside
It is not a caliper. To eliminate sound coming from caliper, I was slightly holding the break pedal.
Struts installed - Red Koni. Installed 70K mi ago.
Is it a bad strut, strut mount or sway bar bushings? Thank you.
 

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veganxxx

Active member
Bad clunks are often sway bar end link bushings (just diagnosed one this weekend). Jack up one side at a time and use a bar to move the sway bar up and down. You can easily see play in the end link bushings.
 

Midwestdrifter

Engineer In Residence
How much space between your bump stop and the lower control arm? Should be around 10mm. If its significantly lower, your ride may be harsh and clunky due to bottoming out.
 

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
Then check your wheel bearings if the sway bar checks out ok.
 

vzapor

New member
Thank you all for your suggestions.
It was a worn Strut Mount Bushing. Tightening the nut 1/3 of a turn eliminated the knocking sound. I believe it is a temporary solution. Strut Mount Bushing needs to be replaced soon. Tools used: impact gun + 24mm socket.
 

vzapor

New member
Few weeks later had same problem on the passenger side. Strut nut 1/4 turn with impact gun fixed the problem. Now I wonder - is it nylon-insert lock nuts that got loose over time or strut mount bushing rubber wearing out?
 

Midwestdrifter

Engineer In Residence
The metal sleeve in the bushings bottom out on each other by design, this prevents crushing the rubber. The knocking occurs when the metal bushing has free play, and the shaft moves up and down, with metal striking metal. Likely what happened is that the nut was not tight enough to begin with.
 

autostaretx

Erratic Member
It takes amazingly little play in suspension items to cause quite an impact ...
..be it noise (the knocks/clunks)
... or handling (i once fixed a VW squareback that had a 0.008 inch difference between a front shock mounting stud's outer diameter and the shock's corresponding bushing inner diameter ... pre-fix test drives felt like it was leaving the road as it crossed paint stripes)

--dick
 

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