Metal clanking sound over bumps

[marc2092]

Been going crazy, completely emptied the boot out and the spare tyre compartment, and I'm still hearing a metal clanging/clanking sound every time I go over a bump.
It sounds almost like some metal is being launched slightly into the air and I'm hearing the noise of it coming down and hitting another piece of metal - like a metal ring on a tube.
It seems to be coming from the rear left of the car from the outside. I jacked it up on the front left and rear tyre and there was no play in either wheel, and I couldn't replicate any sort of sound either.
Pushing down on the suspension also yielded no sounds.

 

[Handy Andy]

Pull back the felt in the back trunk and boot to find the shock tower upper mount...

Might want to check the bolts - it uses two on a metal cup to hold it to the car, while another nut holds the shock to the cup that bolts the shocks "piston rod" to the mount, the other two bolts then mount this assembly to the shock tower support

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The reason this comes up is if the shock got damaged, the cup can crack and eventually fail - causing this rattle.

The Piston to nut also - that grommet can "push out" if the car got into some potholes and or rough road and heavily loaded. It can then rattle around and the upper rod can bang against the cars tower support.

You won't see any true effort unless you take the shock out and test it separately for looseness. For the piston itself tries to seat the whole affair when it's at rest - the noise can be from the extension hitting the cup or making the grommet rattle in the cup.

 

[Handy Andy]

There is also a rear upper cushion on the coil spring - at the upper wheel well crest where the springs upper mount rests.

View that product to replace the OEM one here...
https://www.powerflexsuspensionbush...2030-for-ford-fiesta-mk7-st-2013--89182-p.asp

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[scotman]

It’s also possible that the bushing pressed into the lower attachment eye of the damper has failed.
Given that the noise is isolated to the left rear corner and only occurs when the suspension compresses. That narrows down the point of origin. The only other thing that is possible is the bushing in the swing arm might be sloppy. But, it would cause some rear axle beam deflection that would give you a strange feeling in the ride immediately after the bump.

 

[marc2092]

Turned out to be two things. The heatshield at the back was clunking, making me think the metal noise was also coming from the back. In fact, after securing the heatshield, it was a piece of the coil spring that had broken off at the front left, and was knocking around in the lower mount.
Bought a compression tool off Amazon, so I'm gonna attempt to replace the coil spring some time next week. Thinking of doing both sides to keep things balanced.

 

[SyntheticAtmosphere]

...Thinking of doing both sides to keep things balanced.

This is good practice as the right spring will have had roughly the same number of cycles as the left and could be on the verge of the same fate.
If your struts are still usable, scrutinize the bearing plates while you are in there. And dont forget an alignment after. Good luck and take your time, there is a fair amount of energy in a compressed coil.

 

[scotman]

If the coil spring is broken then the damper is also probably junk. The stock O.E. dampers, especially the rear shocks, are real disappointments. They were failing and or bleeding to death from the start. The basic tuning of the part was less of an issue than the incredible rate of deterioration.
This carried through to the early FRP lowering kits. The dampers in the early kits were so messed up that it took six (6) kits to get a set of matching rate dampers.
This was based on my experience watching them on a shock dyno that measured rebound and compression in inches per second in a force vs absolute velocity curve.
As the dampers were cycled and began to warm up the values changed considerably. The guy who owned the dyno was laughing and Pointed out that we were not matching up the best shocks so much as we were trying to find a pair of random turds that smelled alike."
If you drive around in any city you will notice Fiesta’s with blown out rear shocks, if you are looking for that gently floating undulating behavior in the back end.
That we can just go online and order up a complete set of Koni STRT or Sport dampers with the H&R lowering coils in a “boxed kit” is just fantastic.
Or just as easily buy your choice of Bilstien products. Now we also have KYB Excel G dampers which are a genuinely good quality O.E. replacement that’s actually far better than the originals. For an inexpensive economy car we now have what can only be called an embarrassment of riches when it comes to a selection of suspension parts and upgrades.