S2000 Under The Hood S2000 Technical and Mechanical discussions.

Front end pop/clunk when transferring load under braking

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Old May 31, 2014 | 07:53 AM
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Default Front end pop/clunk when transferring load under braking

Attempting to diagnose and fix a double pop/clunk noise from my front end (it's a quick pop pop with slightly different tone for each pop. once there were three consecutive pops).

I hear it mainly during deceleration when I step on the brakes with moderate to hard pressure at low speeds, kind of like something is shifting under load then returning to position (pop pop). I do not think it's a function of braking, but instead, a function of quickly transferring a load/inertia under braking. I do not hear it under very gradual deceleration. I *think* it's emanating from the front right, but it's difficult to tell.

Sometimes I can get it to produce the noise loudly and repeatedly. For example, I can brake medium-hard multiple times in a row during one deceleration and reproduce the noise each time. Other times (today, after one last round of checks on upper a arm mounts) I don't hear it at all.

New powerflex bushings last summer, EXCEPT sway bar bushings. New shocks and springs.

I re-torqued every bolt I can think of to no avail. No worn dust covers. I was fully expecting to see something something wrong with the sway bar or ends links, but I couldn't tell. I wiggled everything I could get my hands on and couldn't reproduce the noise.

Re-torqued:
Sway bar bushing mount bolts, and the bolts that secure the mount to the body. Bushings look ok from what I can see.
Sway bar end links (they look fine to me)
Front subframe
Shock mounts
Upper control arm
Lower compliance bushing (moved it a bit on accident.. probably altered my caster, but whatever)
Caliper mounting bolts
All bolts that mount to the hub/knuckle (ball joint mounts)
Steering rack
Engine mounts
Tranny mount

What else should I look for? Should I just replace the sway bar bushings and end links?
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Old May 31, 2014 | 08:09 AM
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Can you make a video? To me the usual suspects would be:
Compliance bushings
Sway bar end links
Wheel bearings

Where are your power flex bushings installed?

Also engine mounts you can't really tell they are completely torn unless you almost remove them




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Old May 31, 2014 | 08:23 AM
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i been dealing with similar issue. i hear it from front right most of the time. I been to a few different mechanics and asked some other people. No one seems to be able to pin point the cause.
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Old May 31, 2014 | 08:40 AM
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Originally Posted by gptoyz
Can you make a video? To me the usual suspects would be:
Compliance bushings
Sway bar end links
Wheel bearings

Where are your power flex bushings installed?

Also engine mounts you can't really tell they are completely torn unless you almost remove them
Powerflex for upper A arm, lower A arm, and compliance bushing. All installed last summer, so I wouldn't think the compliance bushing is at fault unless it is no longer torqued correctly. Sway bar, lower shock mount have original bushings (200k miles!). Original end links, ball joints. I can try to make a video, but I don't know if the noise will be audible.
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Old May 31, 2014 | 11:27 AM
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Wow incredible well I would check the following:

Regrease poly bushings.

Check torque specs.

But I'm going to guess:
1) balljoint
2) wheel bearing
3) end links
4) sway bar bushings in that order


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Old May 31, 2014 | 09:00 PM
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You need to check the passenger motor mount. Last if you can. But just check it
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Old Jun 2, 2014 | 05:28 PM
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I'm going to try to make a video after work tomorrow. The noise comes and goes with intensity, but at one point today it graduated to much worse. I could hear the pop when lighter loads were transferring without even braking, and under braking there was almost a scraping noise followed by multiple pop/knock noises. Scraping sounded like it was coming from right in front of the fire wall (as opposed to being say in front of the engine, or concentrated at one of the hub areas) and I could feel it through the pedal assembly.
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Old Jun 27, 2014 | 06:22 AM
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Can't capture it on video, and haven't had a free weekend to do any work on it. But it's progressed. Definitely coming from the front passenger hub area. I hear the pop noise on moderate left turns, when transferring softer loads than before, and I *think* over some bumps. I'm going to tripple check my upper A-arm mounting points, but I'm leaning towards a toasted end link. Thinking I'll just replace both sides and the bushings in a couple weeks.
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Old Jun 27, 2014 | 07:33 AM
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Double check compliance bushings? And what about slider pins being worn ?
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Old Jun 27, 2014 | 08:43 AM
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Compliance bushings are brand new poweflex, installed last summer. They look fine, but I will double check. I re-torqued the slider pins, but I did not remove the boots to inspect. I will perform this maintenance when I put new pads and rotors on in a couple weeks: https://www.s2ki.com/s2000/topic/921...liper-refresh/ Also I'm going to re-check passenger motor mount.
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