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Trying to chase down a loud popping noise in the front suspension of my 98 GS400. I have replaced close to everything up front - upper control arms, tie rod ends, lower ball joints, sway bar end links, Rearward lower control arms and it has new tein street advance coilovers. Only thing I haven’t done is the main lower control arms. But as far as I can tell they don’t seem totally shot with any noticeable play…
The noise is somewhat random. Sometimes it happens in bumps sometimes it doesn’t. I don’t hear it at all on freeway. It’s relatively loud and you can somewhat feel it in the floor when it happens. Appears to be both sides.
it is not the sway bar links binding up, I have tried driving it with the end links detached and still
got the noise. I am about to replace the main lower arms in hopes that that is the culprit, it just doesn’t seem like a control arm bushing noise to me. Everything up front is torqued to spec.
I did not have this noise before I put the coilovers on 2 months ago, and I replaced all the other suspension stuff about 6 months ago when I got the car. I also replaced the engine mounts the same time I did the coilovers, but everything is tight and torqued to spec there.
the car is about a 2” drop. The wheels are not hitting the fenders at all from what I can tell. Pretty high offset - factory is350 wheels.
any ideas here? I am at a loss at this point.
Last edited by tenac2215; 11-13-23 at 03:43 PM.
Reason: Typo
I’ve had this happen on my LS400 but sold it before I could figure it out.
doesn’t really happen exclusively when turning - it can be going straight as well. It feels very random, but it must have something to do with weight shifting
I did not have this noise before I put the coilovers on 2 months ago
Well that should be the first place to start then. Do you still have your OEM struts? If so, I'd put them back on in front and see if the noise still happens.
Well I figured it out. The coilovers were too low. I’m not sure if it was hitting the bump stop or not enough preload on the spring. Or possibly even the upper control arm contacting the body… either way I raised it like 1/2” and it’s not making the noise anymore.
Better than throwing more money at it for no reason lol
Could have been that. When you get to the point of 0 wheel gap (~3" drop), UCA clearance starts to become an issue, especially if you have pretty soft coilovers. It stands out from other suspension noises because it's quite violent and you do feel it throughout the car, so from your description it sounds plausible. Especially since raising it seems to have stopped the problem.
He should be able to put some roll center adjusters (RCA's) (known as drop spindles or spacers in other vehicles) and be able to lower again. I have a set of Megan racing ones on mine with the Tein coilovers as well.
He should be able to put some roll center adjusters (RCA's) (known as drop spindles or spacers in other vehicles) and be able to lower again. I have a set of Megan racing ones on mine with the Tein coilovers as well.
I could be picturing this wrong but I believe RCAs would reduce UCA to body clearance. Lower control arm angle is preserved with them, but they move the knuckle upwards and with it the UCA.
They're good to have for other reasons, but I don't think they solve this particular issue.
I could be picturing this wrong but I believe RCAs would reduce UCA to body clearance. Lower control arm angle is preserved with them, but they move the knuckle upwards and with it the UCA.
They're good to have for other reasons, but I don't think they solve this particular issue.
Hmm, you are probably right, I always thought that's what they were for. I actually went with them for my LS400 brake kit and tie rod end clearance. And that they aid in alignment when lowered etc. But if you think about it, that makes sense.
After already replacing everything else, you might as well replace the #1 lower control arm bushing as well. They do go bad, and if you’re feeling some wobble in the chassis, it’s probably more than just the damn sway bar end links, and yes those can be frustrating. You can buy a set of those main lower control arms, with the bushing already installed for less than $75 for the pair, just my 2cents
11-13-23, 03:28 PM
Popping noise from front suspension
