Help diagnosing a suspension clonk

[jonno1]

Despite my 66 911 having had:

- new bilsteins all round
- rebuilt steering rack
- new wheel bearings
- new suspension bushes

...and there being no free play anywhere and it driving very well etc it still makes a god awful clonk At the front (mainly driver side (LHD car)) over small bumps, shallow potholes. Obviously as there is quick unloading and reloading something is hitting something.

I am wondering if its front torsion bars. We replaced them with slightly larger diameter ones as its a fast road car intended for some mild track use.

With the car at a purposeful ride height (ie one finger ish between tyre and arch) there is a wobble in the torsion end caps when the car is jacked up. If I take that out by tightening the bolt then when I lower the car the ride height is too high. I havent been able to test whether this has stopped it but I somehow fear it wont....

Any thoughts appreciated. Am a bit stuck and a bit daft

[911hillclimber]

My experience is only 73 911 but when you jack the front up there is a clearance between the torsion bar ride height adjusting bolt and the crossmember tube.
The lower the car, the greater the gap. Always thought there should be a locking nut tightened when height is set, but not so.

As to the clunk: are the inserts correctly pinned-into the struts?
Obviously, are the rack fasteners tight esp the one in the smugglers box? (shaft from rack with the needle bearing that locates to the shell via a saddle strap)
Drop link bushes and bolts snug fit to the lower arms and the bushes etc on the anti-roll bar arm ends tight?

[jonno1]

Thanks for the reply

The inserts are all fine and were triple checked. And the bushes are all new and fitted correctly. I will check the rack.

The car was fully spanner checked by a good garage, they even went out in the car down a lane with a chap sat in the front with the bonnet up with a stethoscope! They were at their wits end and then lock down came in so we left it for another day....

[PeterK]

Probably not, but always worth checking for loose battery, something else in the froot


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[rhd racer]

+1 for ARB drop links

[hot66]

What kind of a arm bushes ?

[jonno1]

Elephant racing

[911hillclimber]

Are those the bronze ones?

I had nylon in my 911 for my hill climb years and had to very regularly WD40 them to stop creeking etc, took them out and replaced with rubber in the end. Never noticed any difference in the car.
Hot66 may have put his finger on your issue, lubrication or true alignment.

[KS]

El Chucho had exactly the same problem - tried everything. Even though I had fitted new rose-joints on the A/R drop links, it was only when we drove the car with them disconnected, the noise went away. But changing the drop links did nothing to improve things! Never did sort it out...

[jonno1]

They are not bronze. They do bronze one though.

We used these:

https://www.elephantracing.com/porsche/ ... -bushings/

[hot66]

Just checking because I’ve had elephant poly bronze for maybe 14 years .. last year I got clunking and it was one of the front a arm polybronze bushes. Stripped it and repacked with grease and the clunk has now gone.

With your rubber ones I suppose we have to assume it can’t be that.

Can you replicate the noise in the garage by maybe rolling the wheel back and forth up against something like a brick to try and rock the wishbone ? Is the noise from suspension compression or from lateral movement in the components

[jonno1]

Its hard to replicate it as seems to be only when quick unload-load - wont do it over a speedbump for example.

Its infuriating!

No freeplay anywhere. On smooth roads it handles beautifully. And then clonk. And my fillings fall out my head.

http://forums.pelicanparts.com/porsche- ... clunk.html

Interesting read - I have larger torsion bars.

[hot66]

have you got a pic of youre endcaps & adjuster screws both with jacked up & sat on its weight ?

[jonno1]

I dont but will do.

[jb]

A long time ago I had a clunk like you describe and so took it to Tuthill’s who fixed it for me
Probably not the same but maybe the lock ring?
This is from the invoice


PS Sorry about the image size
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