[NoobCola]

Hey all, I recently installed a set of bc coilovers and after driving about 30 miles or so I began getting a clunking noise from the front. Hard to distinguish if it's the top hat or the sway bar end links. I did a quick check today once I got home from work and nothing was loose. I'm gonna perform a more thorough check on the weekend once I have more time. I've been doing some searches though and seem to be finding some mixed answers, seen somewhere that some grease between the spring and top hat might solve it. Also heard that this is just an issue with bc coilovers. All in all some pretty mixed answers and was hoping anyone with some experience with these coilovers could help me out.

*Edit*
A little more back info on this. The sound is most prominent when going over speed bumps. I softened the dampers on the suspension from 20 clicks up from soft to 14 clicks up from soft and the sound is still there but not as bad.

[Jonny3]

Did you torque everything to spec? I just installed Coilovers on my car and although everything was tight it wasn't torqued to spec so when I went on a test drive it sounded like the car was gonna fall apart. Every slight bump in the road was amplified. So I'd check that out and hopefully that helps solve that issue.

[NoobCola]

During the install I torqued everything down to spec with the exception of the sway bar end links only because my torque wrench didn't fit. But when I was tightening those nuts it felt like it had a stopper on them because once it got to a certain point I couldn't tighten it anymore without excessive force.

[cfm56d7b]

Is the sound consistently generated on both sides or only one?

[NoobCola]

Definitely the drivers side, hard to tell if it's coming from the passenger side

[cfm56d7b]

Few thoughts:

- Are the springs preloaded? 5mm is the usual target. If preload is not correct, the spring will bounce
- Is there fluid under the dust boot? Could be a bad cartridge - and it happens
- Is the top nut tightened correctly?

[Logicoeur]

Definitely get those endlinks checked. They tend to snap and you cant tell unless the suspension is unloaded.

[NoobCola]

They claim the springs came preloaded from the factory with 4mm pre load which is the minimum for this kit. I checked everything and it's tight. The kit also came with new end links and those are fine. I ended up deciding taking it into a mechanic though I don't have the energy to deal with it lol, decided to devote my time dialing in the rear ride height cause it is slammed right now but luckily for me the mechanic said he'd adjust them for free 😁
After initially talking to him it sounds like the spring is making noise on the top hat... the spring compressor I had didn't fit on the bc springs so I didn't put the dust cover between the top hat and spring and hoped for the best 😅

[obert]

Mine do it as well. I have been told it’s the top hat but I am not spending 4-500 on a set to it rid of that little rattle at low speeds. I think there is another thread on this as well.

[brigade24]

Originally Posted by cfm56d7b

Few thoughts:

- Are the springs preloaded? 5mm is the usual target. If preload is not correct, the spring will bounce
- Is there fluid under the dust boot? Could be a bad cartridge - and it happens
- Is the top nut tightened correctly?

point #1 and #3 was why my clunking noise was occurring with my BCs. my preload was set at 5mm (or the width of the supplied wrench...might be 4mm). On one occasion the collar below the spring was loose. on the other, it was the top nut.

The BCs use bilstein internals so bad cartridge is possible but unlikely...I was not given the definition on what exactly "bilstein internals" means so this might be a grain of salt type of situation. I consistently beat the daylights out of my suspension...no leaks so far.

I tightened my top nuts (lol!) and doubled the preload on both fronts springs (adding preload=tightening the collar under the spring) about a year ago...no more noise since.

[NoobCola]

Originally Posted by obert

Mine do it as well. I have been told it's the top hat but I am not spending 4-500 on a set to it rid of that little rattle at low speeds. I think there is another thread on this as well.

Yup this was the case for me, mechanic verified that the noise I was hearing due to the nature of these types of coilovers

[Z K]

Originally Posted by brigade24

point #1 and #3 was why my clunking noise was occurring with my BCs. my preload was set at 5mm (or the width of the supplied wrench...might be 4mm). On one occasion the collar below the spring was loose. on the other, it was the top nut.

The BCs use bilstein internals so bad cartridge is possible but unlikely...I was not given the definition on what exactly "bilstein internals" means so this might be a grain of salt type of situation. I consistently beat the daylights out of my suspension...no leaks so far.

I tightened my top nuts (lol!) and doubled the preload on both fronts springs (adding preload=tightening the collar under the spring) about a year ago...no more noise since.

BC definitely does not use Bilstein internals... they are BC shocks that are made in Taiwan. You can buy replacements for $100.

Clunking over bumps is most likely the top strut nut needs to be tightened. They do not come fully tightened out of the box.

[BoyOhBoyyy]

Originally Posted by Z K

BC definitely does not use Bilstein internals... they are BC shocks that are made in Taiwan. You can buy replacements for $100.

Clunking over bumps is most likely the top strut nut needs to be tightened. They do not come fully tightened out of the box.

Originally Posted by Z K

BC definitely does not use Bilstein internals... they are BC shocks that are made in Taiwan. You can buy replacements for $100.

Clunking over bumps is most likely the top strut nut needs to be tightened. They do not come fully tightened out of the box.

Had BC coilovers on the Lexus as well and this ^ was the fix. Tighten the nut and it'll fix the clunking noise

[Boostedphil698]

I've had BC's on my Civc for 3 years now and they just clunk. BC's don't ride nice. KW's are a way better choice for these cars.

[brigade24]

Originally Posted by Z K

BC definitely does not use Bilstein internals... they are BC shocks that are made in Taiwan. You can buy replacements for $100.

Clunking over bumps is most likely the top strut nut needs to be tightened. They do not come fully tightened out of the box.

while you may be right, the fact that they are made in Taiwan doesn't mean they don't use bilstein internals. Taiwan like anyone else is perfectly capable of sourcing shock internals. maybe bilstein gets its internals from Taiwan??? who knows these days. its not like bilsteins are that much more expensive than BCs...Anyways, if you would be so kind as to provide a source for the information you provided that would be wonderful because i would love to know.

[NoobCola]

Originally Posted by 435i_Phil

I've had BC's on my Civc for 3 years now and they just clunk. BC's don't ride nice. KW's are a way better choice for these cars.

I don't daily drive my car so I can live with them. All in all I am liking them so far. Low speeds is where it can get slightly uncomfortable and noisy. Riding on the freeway is smooth and less sketchy when you're going over 100 the stock suspension was too bouncy for that.

[Boostedphil698]

Originally Posted by NoobCola

I don't daily drive my car so I can live with them. All in all I am liking them so far. Low speeds is where it can get slightly uncomfortable and noisy. Riding on the freeway is smooth and less sketchy when you're going over 100 the stock suspension was too bouncy for that.

Yes BC's do make more noise at slow speeds, never understood that.

[Z K]

Originally Posted by brigade24

while you may be right, the fact that they are made in Taiwan doesn't mean they don't use bilstein internals. Taiwan like anyone else is perfectly capable of sourcing shock internals. maybe bilstein gets its internals from Taiwan??? who knows these days. its not like bilsteins are that much more expensive than BCs...Anyways, if you would be so kind as to provide a source for the information you provided that would be wonderful because i would love to know.

I'm not bashing on Taiwan made products, Taiwan makes some great stuff. But they are definitely not Bilstein internals. Anyone who tells you otherwise is BSing you.

BC - Bor Chuan makes coilovers for many manufacturers including Megan Racing, Apexi and their own coilover line up. You can contact them and ask them to make your own private label coilovers. I can contract them to make me some "Z K SUPER RACING TYPE R" coilovers if I want. Their shocks are made in house.

I went through 2 sets of BC made coilovers on my previous cars within 2 years. The shocks wore out very quickly and are shit quality. It is not worth it and their customer service is non existent. I asked about warranty replacement and they refused so I purchased another set of shocks which went bad as well. Then I threw it in the trash and bought a set of Ohlins.

[NoobCola]

Hate to revive an old dead thread but realized I never posted an update on what I found. Such a weird issue and am updating in hopes this one day helps someone else. The guide pin on the strut that goes into the knuckle broke off and caused the strut to shift ever so slightly but it was significant enough to take its toll on the end links. Replaced the bottom half of the strut and it's been good ever since and no issues.

[RbBugBitMe]

Good find and thanks for the follow up. I'm in the middle of installing my set and noticed my pin is pressed in at a slightly off angle so maybe that'll break off too.

Regarding Bilstein bits, BC does not use Bilstein anything from what I can tell. They do have plenty of dimensions that are similar enough to allow you to rebuild the BC dampers with Bilstein parts. I say parts, but it may really only be the pistons. I'm positive the adjuster bits don't transfer and I doubt the rod seal does cause I just can't imagine Bilstein uses such a shitty rod seal.