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Thumping Sound?
- Thread starter McMestas
- Start date
Thank you DK10438 great reference point. I hope they have the new half axles now. I don’t want the previous version to be put back on my car. It’s just a problem waiting to happen. Thanks to all for the great input. I guess this problem has been going on for a while. My S car has less than 15k miles.
I've had both left and right replaced 4 times. The first time was with the original part number. The last 3 were all the revised part number. The problem returned 3 times (twice with the revised number). It hasn't the third time but I'm sure it would if I removed my 3d printed lowering links and reinstalled the stock ones.
I wanted to follow up and report what the SC concluded as a result of my complaint of a thumping sound coming from the left suspension area. I took it in today and the technician clearly heard the thumping sound, I left it there and about an hour later they notified me that it was repaired and ready for pick up. They told me that they re-torqued the front suspension fasteners. I drove it home set on standard and drove it for more than 50 miles. Everything was back to normal.
dark cloud
Active Member
That's good news. Typically the suspension play is noticed going over bumps, and acceleration is not the trigger. At least the half shafts are not the problem but now one wonders if there is a whole batch of later model S's maybe with some suspension pieces that were not torqued to a proper value from the factory?
Did they indicate which nut? or did they just torque them all?
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They were not specific. No parts were added. The warranty invoice merely said “ re-torqued the front suspension fasteners.” So I’m assuming all. The technician did mentioned on the test drive when I initially took it in, that he could feel the vibration on his feet, when he was sitting in the front passenger seat. I hope that’s all it was.
Wow. Have problems on so many levels with that diagnosis.
First, the only "suspension fasteners" are large bolts for each of the suspension control arm bushings. The bushings of of each control arm on the frame side are held in place between two plates welded directly the frame. The bolt clams the plates tightly on the metal ring of the bushing.
Loose bolts wouldn't make the kind of sound you heard(unless they were REALLY loose...keep reading).
That said, if the were loose, then simply tightening them down is not correct as they were loose long enough for the metal part of the bushing to rotate back and fourth between the clamping plates regardless of wither it's an upper or lower control arm. The hub side of the controls arms also have their bushings clamped between two plates on various parts of the hub.
If any bolts were loose and you drove around more than a hundred miles or so, the bushing bearing nubs would have worn off. Each bushing has a metal ring with little outward dimpled numbs that prevent the center bearing from slipping in their mounts. If these numbs wear off due to a loose bolt, that control arm must be replaced.
Lastly, if the noise really was caused by a loose control arm bolt, then it means it was really loose and over time the clamping plates were bent outward at which point you'd have frame damage since the clamping plates of each frame side bushing are part of the frame.
I'd ask them to be very specific about exactly which bolts were loose for each upper or lower control arm and if it it was frame or hub side.
This scenario of frame damage is horrifying! I recently had control arms replaced in the front [and previous half shafts replaced from the rear: "REAR HALFSHAFT 36 MM, PERFORMANCE (1007719-01-B)"]. I noticed the control arms were replaced with "2nd generation":
I am wondering if this "2nd generation" will result in less control arm failure in the future?
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