AVSRacing

OK so I finally had the chance to take off my rear wheels and check out my suspension today.

I've been having clunks from the rear suspension since day 1 after installed BC racings. At first I thought it would be tires, but its not. Some members suggested looking at the pre load. And after finally getting the chance to take a look today, I don't think its the pre load as I could not turn the springs by hand. Also I've checked the 3 bolts holding the shock and those are all tight too.

any suggestions what It could be? I've only had these on since like October.

BayAreaLex

Check the torque on the top nut.

And you aren't the only one. There are tons of people with various C/O brands that complain about clunking and rattling.

I thought my rear rattling was attributed to the pillow ball wearing out in the top hats but replacing the rear hats didn't fix the issue. It wasn't the top nut being loose, spring perches being loose, nor preload. I'm now replacing the shock itself to see if it makes a difference.

Can you be more descriptive about your clunk and when it occurs?

AVSRacing

I've actually pmed circuit motor sport today, I bought mine from them. They told me to check preload, top nut, and lower bolts.

I've actually checked the 17mm top nut today and it seems tight. Does any one know how many pounds it should be torqued to? I torqued it to 30 pounds with my torque wrench and the whole center shock part was spinning with it. Then I tired a 5mm hex in the adjustment **** and spanner wrench and it was tight, I couldn't tighten the spanner. But the clunk/ slapping noise is still there. It's weird cuz it mainly occurs when there's very small imperfections in the road, but its very loud, considering how well insulated the GS is. Just sounds like something is loose and is clunking, slapping around. This is from very slow speeds too, like up from 5mph rolling, and just gets worse if you go faster.

The noise only occurs in smaller residential streets where there's lots of very small uneven cracks, unevenly paved sections from repaving water pipes from new houses. On main roads its fine.

BayAreaLex

What you are describing is exactly what many people are complaining about in the rear...

Over large imperfections, it's fine. But over really small imperfections the faint clunk (more like popcorn popping) can be heard. It can't be heard over big bumps or at high speed. Really weird.

The 17mm nut takes about 40-60 ft-lbs. I can't seem to get there without breaking the 5mm hex, so I just hit it with a small impact and call it good.

But ya, I haven't been able to figure mine out yet. It may be the shock itself. I haven't been pleased with coilovers in general due to annoying rattles and faint clunks that weren't there before the coilovers.

AVSRacing

Ya its exactly what's happening. So weird. It's quite loud over small bumps but fine over bigger ones so it doesn't make sense. There's no way I can torque it to 40 by hand with wrench and hold the 5mm hex

FrankT

You need to use an impact wrench to get it snug.
I believe that's what I did. I know that if the shock is not tight w/ the upper mount it will knock and bang.

It happened to me on a Supra I refurbished, I had to remove all the trim and molding again just to tighten the top bolt on the rear shock both side because of the knocking and banging in the rear suspension.

Good luck...

BayAreaLex

Ya, you can't really torque to 40ft-lbs using the 5mm hex without breaking it off in the strut (ask me how I know).

Most people hit it with an impact. Either a small impact or a normal impact with a lower air pressure setting. What you can do is take your impact (assuming you have one) and experiment with how much torque is applied at different air compressor air pressures, i.e. 60psi, 70psi, 80psi, etc. Verify the torque with your torque wrench at each air pressure (using one of your wheel lugs) and find that 60ft-lb sweet spot for your 17mm nut.

But I don't think that's your problem. If that 17mm nut is loose, it will bang over all bumps at all speeds. This faint popcorn popping we are having is not 17mm nut related...

1sWt2GS

iTrader: (6)

I have some very faint noises but have just learned to deal with them. And you talking about the 3 17mm bolts?

AVSRacing

^^ no the center one, on the bottom of the adjustment ****

BayAreaLex

The 3 nuts are not 17mm, the center one on the strut shaft is.

AVS, keep us updated on your progress. I've swapped the sway bar bushings, sway bar end-links, Megan coilover top-hats, and made sure the coilover rings are tight and the preload is set correctly.

AVSRacing

Well my cars going in for brake job this weekend so I'll get my mechanic to take a look and double check everything to see if he can find anything.

BayAreaLex

There's evidence suggesting possible issues with BC and older generation Megan coilover lower mount bushings. That might be worth a look... sounds possible to what we are experiencing.

https://www.clublexus.com/forums/gs-...ks-due-to.html

Let's keep each other in the loop on this one. I'm confident we can solve this.

Evlc36

Hmm, this interests me, as I have HSD coilovers and experience the exact same annoying rattle over minor imperfections on the road from the rear - only on one side though!

BayAreaLex

Ya, mine is coming from the passenger side rear primarily. I'm going to focus on that lower mount first.

I called Megan racing for replacement bushings but they said you have to buy the whole lower mount for $65. F that.

I'm sure I can figure out another solution once I have the dimensions of that eyelid diameter on the lower mount.

For the record, I've also replaced the sway bar bushings and end-links in the rear which didn't help.

1sWt2GS

iTrader: (6)

same here, i'll try tightening the middle 17mm nut, im afraid to break the adjuster though.