'18 tS front pop/clunk/knock fix - strut bars
 

The Symptom
Right off the lot (first heard it on the drive home from the dealer) my tS would make a loud pop/clunk/knock noise occasionally going over bumps in the road while driving. The noise was much more consistent when driving the car over speed bumps at an angle and seemed to happen when the first wheel would hit the apex of the speed bump.

I drove around for a bit just listening to see if it was some kind of new car adjustments working themselves out. On my drive I have a set of speed bumps that I go over regularly and after many repeated drives over them hearing the same noise I concluded that this was not going to just work itself out.

The Fix
Going off a hunch of where the sound was coming from, how it sounded, what was triggering it, and the fact that my previous '15 BRZ didn't make the noise, I figured it was related to something specific with the tS so I started with the front strut bars.

Grabbing the longer part of the STI strut bar I gave it a good tug up and down and could feel a bit of play on the passenger side. Not anything crazy, but it did move a little more than I thought the pillow joint should allow.

Next, with a deepish socket and extension I tightened all the mounting bolts/nuts in the attached image. Not crazy tight but a good solid turn with a ratchet on each. Be careful with the ones closest to the firewall, they're not studs and are bolts that go into a thin piece of sheet metal so don't overdue it with those and strip out the sheet metal. I think they were all 14mm. I should also add that none of them felt like they were overtly loose, it was just possible to tighten them down a bit more than they already were. After tightening them all down I did the same tug up and down on each strut bar and it felt a lot more solid than before.

The Results
Noise is gone. Been driving over the same speed bumps as before multiple times since I tightened everything up and the car no longer makes a noise going over them. Gone over some bumpy roads that would have probably made the noise before and it's all good, no noise.

Hope this helps!

I’m glad I wasn’t going crazy and someone else was hearing something similar. Going to go tighten this right away. Thanks!!

I tightened mine. They were already pretty snug. I turned it about 2mm. Didn't want to risk snapping the stud.

Grab the bars with your hand and shake them to see if there's any slop. Mine still clunked, but I think it was due to shaking the bars but went away after a mile or two of bumps. I think the bars just have to settle back into their joints.

I did this on mine after initially being able to replicate the noise on the right bar by shaking it, tightening it worked for a few days but unfortunately the noise has returned. It happens a lot during the first 5 minutes of driving then goes away for the most part unless I hit a big bump or something. When I bring it in for service I guess I'll just have to mention it, annoying issue to have in a new car.

Yes this is exactly the same as my TS V bars (I have 13 BRZ). Pulling out my garage the front suspension goes pop pop pop but after driving a bit it all goes away.

You might try some loctite on the threads. :iono:


humfrz

Dang, sorry to hear it came back. I'll keep my ear open to see if mine returns as well. I was going to mention it when I take it in for it's first service. Could be the draw stiffeners http://www.seriouswheels.com/2014/r-...2560x1600.html

Funny thing is that these v-bars were installed from factory to increase driver confidence and now these sounds ...

Mine also is making this noise, going to check this out right now...

Had the noise come back on my ride home from work today. Went over some manhole covers under the left front wheel and each time it made the knock. Later in the drive I went over some more manhole covers and the noise was gone. Really seems like when the car sits there's something going on with the v-brace that works itself out with a "clunk" when you start driving again and flex the chassis...then it goes away for the rest of the drive.

If definitely does it a lot less after I tightened the braces down compared to before but it's still around.

Found an old thread with what sounds like the same issue but with the stock v-bars.

https://www.ft86club.com/forums/showthread.php?t=72378

Yep, this issue is not just tS specific, it happens on regular FR-S/BRZ V-bars as well. I re-torque mine every now and then; spec is 12 ft-lbs (not sure if it's different for the tS bars). In my experience, it's usually the ones near the firewall that come loose. The ones by the top mounts are usually fine.

Ok guys, I brought my car in early for an oil change (after run-in). I also had them look into some clunking sounds that were coming from the rear (another thread running on that). Well they worked on that issue. After leaving the dealership I started getting the clunking on the front. Got home, opened the hood and sure enough one of the V-bars has movement in it. Wonderful. Right now the car is cooling down so I will investigate further. I think mine are on the top mounts.

There should have been no changes in the condition of the vehicle, the only difference that I would think there is that the car has been lifted up. Could this have contributed to the V-bar(s) loosening? Body flex? Something to think about.

Sounds like the STi V bar bolts are coming from the factory looser than they should be.

I also noticed that my flexible V bars clunk like crazy when I preload pressure on the ball joints (pull two sides of the bar together to put pressure on joint) before tightening down.

I recently loosened all the bolts and just let the flexible V bars lay there without any pressure before tightening down. The bars stiffened up and I have a dramatic drop in noise, even though its there for 1 or 2 clunks in the morning.