924Board.org

[canyonblaster]

931 Gents:

while under load during left hand cornering, car makes an erie clunking/scraping sound. seems to come from right side of car. it has done this ever since i bought the car and my mechanic can't seem to find the issue. he has replaced both right side wheel bearings (F & R), and can't find anything via physical inspection up on a lift. The sound is kind of like something is rubbing or scrapng. Only does it if driving the car a bit sporting, backroad rippin', etc. Doesn't do it if just tip toeing around town.

Otherwise car feels ok. the sound is the issue, doesn't seem to actually affect the cars handling, feels tight and solid, even when pushed a bit...

Any ideas? Thanks!
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PCA Licensed Club Racer & Driving Instructor Current P cars: 1981 931
Past P cars, 1985 944, 1987 951, 1990 911 C4, 2002 Boxster S, 2005 996 GT3, 2013 911 C2S
Daily Driver P cars: 2008 Cayenne GTS, 2013 Cayenne GTS

[emlynbeagler]

Mine has done this for several years. It sounds to me as though the noise comes from somewhere in the torque tube. It has baffled several specialist garages and now I just put up with it.

If anyone has any fresh ideas (not wheel bearings, exhaust, gearbox mounts, engine mounts, seats, any suspension component at all), do let us know.
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1984 924 Turbo
2017 Alfa Romeo Giulia Quadrifoglio
2017 Isuzu D-Max
1974 Moto Guzzi 850T

[ideola]

Right side front or rear?

If the upper strut mount bushings haven't been replaced, they are almost certainly beyond their life expectancy. I have measured several mm of difference between new and old versions of these bushings; as the rubber ages, it loses its ability to rebound from compression, and the bushing goes flat. You can't see this from visual inspection alone, you have to compare it to a new bushing (which again would explain why the shop may have difficulty isolating it). The old compressed bushings introduce slop into the strut assembly. The spring might be rotating in the seats, or you might be getting other anomalous related behavior.

Here is a pic from a related thread that illustrates the difference between old (collapsed) and new bushings:

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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

Is it a rotational noise, or a clunk from compressed suspension? What size tires are you running, and on which wheels? Condition of the calipers (are they clean and properly lubricated)?
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[!tom]

Check for:
Brake line rubbing (front, against tire)
Brake line rubbing (rear, against fender)
Sway bar (both front and rear)
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78 924 NA
5-lug

[Paul]

Check your engine mounts, I've seen this cause the waste gate to hit the frame.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[GeorgeV]

Just like Dan, I had the exact same problem and it was the upper strut mount bushings on one side. I figured it out by comparing the height on one side to the other side; if they had both been stuffed it would have been harder to tell.
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1981 932 with mods:
http://www.924board.org/viewtopic.php?t=37921

[canyonblaster]

[leadfoot]

put your car up on jacks and take the load off the wheels, and lock the rack in position with a conical bolt.
get in there and shake the crap out of all all the parts starting with the wheels to test the bearings and the ball joints.
Then remove the wheels and test the struts, sway bars, hubs and tie rods etc... and inspect all the bolts on the struts,calipers (bolts/spring clips) and sway bars for tightness. Check your right side mount, the one with the spring, these rust, break and fall to bits.
You'll soon find where the movements coming from (up down/side to side), somethings worn and you just need to pinpoint it.
with the load off the parts it should be easy enough to move.

when things do move clunks are heard through either parts contacting, manifold downpipes, heat shields, dust shields etc, look for these fresh contacts and signs of scraping or rubbing paint or fresh metal swarf.
Stu
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

[Mark d]

Sit on the front wing where the noise is coming from with the engine running!
I had a similar noise and only by chance noticed the noise when i sat on wing!
It was a collapsed engine mount which led the steering shaft to touch the engine whilst suspension loaded on cornering!!
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1980 924 Turbo S1 - Monaco Blue