BC Racing Coilovers - Knock?
 

Let's get a general consensus for BC Racing owners. I have talked with 3 other people who claim that their coilovers are making a knocking noise in the rear over bumps. I'm also hearing this noise. So, post if you have the problem.

If you have different coilovers and still hear the knock(kind of like a pinball noise) comment as well!

Your top bolt has simply come undone. Common. Go tighten it down.

We took out my coils and retightened every bolt..still making the noise.

i mean mine make a lil noise but its aftermarket parts its not going to feel like or sound like stock so it doesnt bother me but thats just me

BC are low rating coilovers, you get what you pay for

Mine makes a squeaky spring noise when it rains really hard

I have BC's on both my cars, can get a slight "knock" in rear only going over bumps at slower speeds, cant find anything loose. dosent bother me.

i had BC coilovers on my old car and my friend (who had an Infiniti G37x, G37s and now BMW 328i which he had BC racing on all of them) and I had slight knocking noises aswell. So i'd say its "normal"

Bcs FTW

Welp, seems like it's normal. Hahah.

+1
HSD would be my First Choice for what you pay:)

This is my first set of BCs and i have the slight noise in the rear, my friend with a Genesis coupe with BCs had the same issue and tightening the top bolt (under the dampening screw) fixed his issue. I will try this tonight and post back.

BTW my issue is only the rear driver side, so i don't believe think the noise is normal, then again if after i tighten this screw doesn't fix the issue i will try to reach out to BC for their input.

I have one of the first production kits on my car. Zero noises under any conditions and my car is autocrossed/driven hard as much as possible.

You guys with slight noises need to isolate where its coming from and contact BC about it so they can help you figure it out.

try tightning the lower bolt more (way bast the recomended torque spec)

on cars with similar lower attachment points that's usually the issue with aftermarket pieces.

do you know what the torque specs should be?

somewhere between damn-thas-tight and i'm-gonna-need-a-breaker-bar-for-this.

you see because the damper is cupped in the lower control arm, you can't rely on the torque setting accuracy because the control arm flexes, the BC unit may have the lower attachment point micro-meters thinner than it's supposed to be so you have to bend the "cup" inward to really clamp down on the unit.

Remember that the damper pivots by way of the bushing flex, it does NOT pivot on the bolt, so if its not tightned properly it will shift around and that could be the reason you get the clunks.

at least this is how it was on my VW.

thanks this sound just like my issue. I'll try this when i get home tonight and post up results. lets hope this is it :thanks:

i am going to try this now on mine i know it helped in the front when i did it i just cant figure out of the get to it without taking everything apart. is there a way to remove the dampening screw i know there was on my megan coils i had on my genesis

nice i was told that this dampening screw should be removable. Let me know how you make out!

so got my alignment yesturday, and they did a great job, they also tighten all the top bolts on all corners and no more knocking noise for me!

any one in PA or NJ that need alignment RTTuning is the way to go!

I'll contact BC over the week and see what we can figure out.

Let us know what you find!

I had that issue on my Stance Super Sports. I took out my interior and tighten the top hats problem solved.

Had the BC coilovers installed for over 5 months now. Never had the clunking issue. But after my first trackday, the front passenger side coil started clunking during steering. Stopped along the road and took a look, the top nut got loose. Tightened it up and didn't hear any noise again.

Knocking seems to be quite common for them here in Taiwan (and I believe they are made here -_-)

Is the dampening screw covering that bolt?

Yes.

so is the general solution to tighten the top hat nut underneath the damping setting?

Hi i write to you cuz i have the same issue from rear left coilover, i live in italy and i had buy my coilovers from UK...
After few controls BC decide to send to me 2 new rubber top mounts but i am afraid that not fix the problem, i have read who some people had fixed the issue with replacement of internal cartridge,do you know somebody who have fixed this problem with rubber top mounts?
Please can you sent to me any documentation or the mail received from bc racing to talk with reseller for have the same treatment.
There are some news?
I copy here what bc racing have tell to reseller:
"BC have replied to say that recently they modified the C-89 rear top mount so they will send a pair of these rubber rear top mounts for you to try to see if that eliminates the problem. They have said some people have confirmed the noise goes once replacing the .dampers with the new design. They have asked that you please try these and then confirm whether or not you still have the issue as they want to get to the bottom of it for you."

Is there a way to tighten the rear bolt without taking the coil over off of the car?

Peel back your trunk lining, take a ratchet, and tighten it down. Just remove your dampening adjustment knob (if applicable)

Air Bags For The Win

I had BC coilovers years ago on my WRX. They began knocking about three months into ownership.

Things to Check...

Tighten Strut shaft top nut.

Check the spherical strut mount bearing for wear.

Check spring preload. 5mm preload on the spring seat is a good starting point.

Check swaybar endlinks

If none of these are your problem, try to recreate the noise by bouncing the car at the corner where the noise is. I eventually tracked the clunking to the struts and it was internal clunking from the shock/struts. They got progressively worse.

In the end my BC coilover valving was shot and one more autocross finished all four struts. They ended up needing full replacement struts. I hope you guys have better luck with yours. Mine lasted about eight months. Rember this was when BC first was released in the US. I hope they have improved since then.

Thanks thats helpful actually ill set some preload I never had set any before...

Any idea if they come out of the box with any preload?

Some coilovers do, some don't. If you can spin the spring and all of the perches freely, there's no preload set, but I've heard of some manufacturers shipping their products pre-preloaded.

bc racing have send to me new top mount but the noise continue... i have a question: have somebody tried with rear lower camber arms for fixing the problem?

hey guys, so i got bc coils about a month ago, i am getting like a squeaking sound in low speeds, and a knocking from the rear left wheel. any ideas?

I have the same knocking/clunking sound and occasionally squeaking in low speeds.
Im on Megan Street series.:cry:

Yeah i have no idea why it happens