Clanking from rear end on turning

[Nikkum]

I hear a clanking noise from the rear end when turning. Never when going in a straight line. I cant find any loose components when the car is static. How can I narrow this down?
Any help greatly appreciated,
best
Nick

[Nut124]

What kind of a noise?

Does the noise sound like it is internal to the diff? Or like a suspension clunk? In theory, the differential gears could be worn and be binding during a turn causing tire skip and/or subsequent suspension noises but this seems unlikely as the gears are stationary most of the time and rarely wear, unless one runs different size tires L/R.

I assume the panhard rod is in place properly?

[18Fiatsandcounting]

Another suggestion is to check that the rear springs are mounted correctly in their "seats", and that they're not shifting. And that the shock mounts are tight. Top and bottom on both springs and shocks.

-Bryan

[FiatRunner]

I second what Bryan is saying.

I spent weeks chasing a noise in my rear suspension after doing a rebuild, just to find that I hadn't tightened the lower shock mounts all the way.

It's always worth your time to do a simple nut and bolt check when working out a suspension issue.

[Nikkum]

Thanks guys for your advice. I don't think its the differential as its more of a clunk than a grind. Turn and a background clunk clunk clunk from the innermost rear corner until you straighten up then stops. I've also noticed today that its more noticeable after the first few turns of the day.
Great suggestions and I will look at the various bolts and the spring seatings. Ill check the panhard rod joints if I can.
many thanks
Nick

[18Fiatsandcounting]

Could also be a bad wheel bearing, although this is usually more of a grinding or clicking noise than a clunk. And, if you haven't already, check the oil level in the differential. Might not be a bad idea to drain and refill if you haven't done this in a while. Make sure to use "EP" (Extreme Pressure) rated oil, 80W-90 EP if I recall.

But, it does sound like more of a suspension issue than a differential/rear axle issue. Does the problem get worse (or better) if the car is fully loaded with a passenger and some weight in the trunk? Bag of sand, dead body, that sort of thing.

-Bryan

[Nikkum]

Thanks so much for your help guys. I may not always get the solution from the Forum (big ask when you havn't even seen the car anyway!) but 9 times out of 10 it makes me think harder and closes down on a solution.
I have found the culprit. Suspension and panhard all tight. I noticed the wheel moved slightly compared to the axle in all directions. When I jacked it up and took the wheel off moving the disc pretty much replicated the clank noise. I reviewed the various axle diagrams and realised there were no wheel/spacer locating pins present on either rear wheel hub. I wondered whether this could be the cause, but the wheel is connected to the disc and hub by its four bolts so wasnt certain. Anyhow put two new locating pins on each side and clanking resolved.
The pins obviously fix the spacer disc (as well as the wheels) in place on the later spider models and obviously if its not fixed by these it clatters a bit particularly when turning corners when presumably the wheel bolts don't fix so well.
Thought you would like to hear how it went and again, I'm v grateful for your kind advice.

[Nut124]

Glad you solved the problem but I remain a bit doubtful about the cause.

I had a strange noise in a subaru years ago that I could not figure out. The car was howling on the hwy and clicking at very low speeds. If you pushed it in neutral it would go tick or click every few feet it seemed.

It turned out being loose wheel bolts. Snug but not tight. The wheel was shifting slightly on the hub every 1/5 of a turn making the click as it shifted. The last one to have the wheel off was the local sub dealer service.

Perhaps you had something similar.

[18Fiatsandcounting]

I reviewed the various axle diagrams and realised there were no wheel/spacer locating pins present on either rear wheel hub. I wondered whether this could be the cause, but the wheel is connected to the disc and hub by its four bolts so wasnt certain. Anyhow put two new locating pins on each side and clanking resolved.

Good to know, Nikkum, and I would have thought that the 4 lug nuts (tightened sufficiently) would have been sufficient. Apparently not.

-Bryan