Clunking on hard cornering from front suspension
 

First, I searched and could not find anything definitive regarding this issue:

2013 FRS 30,000 miles, set up for D Street as follows: Koni Yellows, Strano front sway bar, RPF1 with Bridgestone RE71R's, crash bolts.

On my 5th and 6th runs at an autocross yesterday, I had clunking on hard cornering (and the clunk seemed to occur when turning very hard left and right). I thought it might be the clamps that retain the Strano front sway bar from sliding side-to-side, but I tightened those and the bar looks centered to me and had no effect.

Clunking seems to be best replicated by turning hard right (about 50% as hard as a hard autocross turn), and by entering a driveway ramp (uphill) at an angle turning right, so that the front right goes up first, and then when the front left wheel goes up, I get a clunk. I.e., in both instances, when the left suspension is compressed and/or when the force is pulling the left wheel away from the car i get a clunk.

Clunk feels like its at my feet and is relatively loud/very noticeable, but does not seem to upset the car very much.

Thanks for your thoughts in advance.

You have checked for the obvious, a front wheel lug nut not properly torqued? Heat cycling of the wheel/hub and brake disc can loosen a lug nut randomly and fairly commonly.

A long shot would be the steering rack moving in its bushings?

Otherwise, could be a failing shock, they tend to clunk when the internal valving starts failing. Check for oil seeping out of the left strut. They can fail without leaking. I've had konis fail internally, no leaks which I thought was due to a PO bottoming the rear suspension on a car lowered too much. I don't know that but too short springs can result in shock running out of stroke. Front struts are very robust though so this is unlikely.

LCA bushings sometimes fail but not usually at low mileage or age.

Roll bar drop links are another common source of clunks if they fail.

I assume you have jacked up each front wheel to full droop and checked the front springs are fully seated correctly. Check the bump stops are still intact.

Thank you for your thoughts. Not loose lug nuts. I doubt it's a blown shock as these are set at half turn from full soft, in the car for only three thousand miles and were not making any weird noise two days ago. Not leaking. Stock springs seated correctly, bump stops intact, and sway bar end links are good and tight.

I've checked the top strut bolts, the three top strut mounting bolts on each side, and the strut braces and all are okay. Lower strut bolts okay. Sound seems to be coming from lower than that.

I have experience with loose wheels, bad end links, binding upper strut bearings on other cars and this clunk is not like those sounds. It sounds like a loose rear control arm bolt on a miata but on the front, and those bolts are tight. It doesn't have the feel of lca bushings going bad and I can't imagine they are the problem - too new and not abused enough.

Are the steering rack bolts that come loose the two main bolts that connect the rack to the subframe?

Thank you. I am going to pick the car up for the third time today to hunt around.

Or bad front hub bearing.

Thank you. My experience with bad hub bearings is a droning noise, not a clunk. And if was at the point of clunking, the wheel would be wobbling. Wheel is very tight and both bearings sound good when I spin them by hand with the wheels on. I think the clunk must be coming from something else.

Or bad front upper mounts.
We can go down the list but there's only so many things that are mounted on the front of the car between suspension and chassis.

I saw a thread suggesting this. I've had bad upper strut mounts on other cars, but typically that has a sensation of binding up the spring, and it letting loose causing a sound. This feels different but if I cannot get the sound to go away by taking out the sway bar I will likely turn to replacing the upper strut mounts. Thanks again.

That's not the sound.

A loose or bad upper strut mount is like bad coilovers or if your shock nut was not tightened properly. It feels like someone taking a hammer and tapping your front shock as it moves up and down.

A bad stock mount can be easily seen from the engine bay, the rubber will look like it's cracked or deformed.

A bad aftermarket pillowball upper mount requires disassembly to inspect properly.

Back to the simple, the crash bolts could be shifting. Put a paint mark along the side of the suspension piece. Hard cornering will shift the mount but bolt will still seem tight, retorque it.

Yes, this does not describe the sound I am hearing and my stock upper strut mounts looked fine and felt fine a few months ago when I put the Konis in. Mine is a once-at-a-time clunk when compressing the left front suspension that feels like it's coming from a control arm or fsb. Thank you.

Have you checked for the endlinks or sway bar hitting the control arms?

90% of my suspension noises on this car have been end link related, and getting that lower nut can be a PITA, the other thing I can think of is the sway bar mount plate thingy.

Crash bolts remain tightened to 120 lbs and no sign of shifting. Fsb supports are tight. End links were not hitting control arms 3 days ago and i double checked the clamps that keep the fsb from sliding back and forth.
Sound is best described as a "knock" and occurrs at about 20% of max autocross force. My plan after driving in to work today is to double check the nuts on the top/center of the struts, and if that doesn't work, take out the end links or end link/fsb assembly entirely and see if that fixes it. Thanks again for your input.

In my experience top nut knocking occurs without any steering input, you can hear it over a bumpy road.

Best of luck.
:cheers:

I am 100% positive you are hearing a swaybar endlink. Check that out, make sure it's tight and doesn't wiggle. The endlink will not hit the control arm. The noise is coming from the ball joint inside the rubber boot of the endlink. The smallest amount of play will cause a clunk or knock, and unfortunately we can't see it since the ball joint is on the inside of the rubber boot. Even if it "looks" tight after checking every thing, replace it and see if the sound goes away they are cheap to replace anyways. I know this because I had this sound on my Celica, and fixed both links and the noise went away. I just fixed a Mustang with the same noise after some "mechanic" told the guy it was a bad wheel bearing. When he said he was still hearing noise after we replaced the "bad wheel bearing", I sat in his car, we heard the noise and told him his mechanic was wrong. I immediately knew it was the end link. turns out when we checked it out, the endlink was wiggling and loose or just straight up broken. Went to advanced auto and just bought something cheap since that's what he wanted and didn't care. Placed the new part in, all noises went away.

Check the strut nuts!! The ones that hold the strut to the top hat.

Everyone is asking about things being loose but to me it really sounds like you're describing contact. I'd take the wheel off and look at the inner edge and barrel of the wheel for evidence you're hitting something, as well as the inside sidewall and corner of the tire.

Also, swaybar end links sometimes hit the body of the car at steering lock with coilovers... Havent heard of Konis but perhaps the end link is hitting with steering in which case you may need to swap the end link to the other side of the tab on the strut.

Depending on size of the RE71Rs, if wide enough, may even be hitting somewhere on the fender liner or inner body.

The only loose suspension I've ever heard that was a definite knock is, as has been said before, a loose endlink so do check those.

I'm going with swaybar endlinks too

Since I fitted a Whiteline bar to the front of my car with the very nice urethane bushes and proper robust and adjustable drop links Whiteline supplies with their bars I will always try to fit proper drop links and bushes in any future roll bar install. Reducing the lost motion you get from stock type soft rubber bushes and flimsy drop link ends significantly improves the feel of the front roll bar. It is also a real improvement in performance. The lost motion reduces the effective rate of the bar.

Seems like something I am experiencing. I have noticed in for at least a year. I hear it coming in or out of driveways. When on track, and sometimes during autox(don't pay as much attention). I get a solid 1 "click/clunk". Was not thrilled when It happened this weekend after all the suspension work.

I found that my one set of wheels did rub, added spacers to prevent that issue. Noise still happened.



I found my sway bar hit the the control arms. Added shorted endlinks to correct that. Noise still happens.

I also have replaced LCA bushings, and added aftermarket camber plates to my coil-overs. Noise still happens. While this was happening, I checked most of my suspension.

I do have an aftermarket steering rack lockdown kit, I am wondering if that is related. Going to try and confirm my recent alignment as well as check all the bolts again this week.

Did you tighten the endlinks down with the car in the air or with weight on the wheels?

all suspension parts were torqued with the car at static ride height with weight on all for wheels. Thank God for drive on lifts.

I'm having the exact same issue after installing Konis and a Strano front bar. I installed new OEM links in the front, and am starting to think that replacing them with Whiteline links might resolve the issue. Seems like people with the Whiteline endlinks don't have this issue, at least not as much as people with stock links.

I have same problem during low speed turning (Megan coilovers and stock end links). I have a pair of Whiteline end links waiting to go in and will update everyone if that solved the issue.

It is possible to have the Strano bar with Konis and stock end links be completely quiet. I would double check to see if the sway bar is centered (which you can do by eyballing it) and the two clamps that keep it from sliding laterally are tight enough. I understand that if it is not centered, the end of the sway bar can come into contact with the lower control arm during travel.


For me (the OP), I bought two new end links and installed them which took care of the problem completely. Thanks to pgranberg11 for confidently pointing me in that direction. It finally began to sound like an end link in "my mind's eye" after reading your post.


Embarrassingly, it turns out that one of the nuts had come loose on one of the end links, and it is likely that had I more carefully checked them I could have saved myself from replacing the end links.

Always check for loose nuts. They can be dangerous.