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I got my hands on a low mileage (~10k) low track use (~4 track days) set of Ohlins for my GT3 which had original shocks going on 125k miles with unknown history of shock rebuild.
The Ohlins increased cabin noise in the rear considerably and I have some serious 'clunking' going on with FR and RR that is only noticeable over low speed bumps. High speed performance is fine but that doesn't really work in the neighborhood. I also have the Tarrett links in the rear and guessing this is adding to the noise but its not acceptable 'as is'.
Is there any rubber component that mates btwn the top of the shock housing/chassis to help deaden said noise? Guessing the clunks are internal to the shock and reflect need for a rebuild though surprised this would be needed after such low mileage.
Sounds like either drop links or shock mounts. I would start by unhooking the drop links (and then going for a drive) on that side and checking torque for the shock mounts. Are the rear shock mounts aftermarket or stock?
I think I just took them off the stock shocks and transferred them to the Ohlins. Interesting causal factor...I’ve chased drop links before and don’t think that’s the cause.
Ohlin USA not answering and Bilstien in San Diego says they quit doing rebuilds on OEM components (considering tossing the factory suspension back on but really like the Ohlin spring rates).
I’ll dive under this weekend and have a peek at the shock mount.
I think I just took them off the stock shocks and transferred them to the Ohlins. Interesting causal factor...I’ve chased drop links before and don’t think that’s the cause given I didn’t disturb the rear when I swapped components.
Ohlin USA not answering and Bilstien in San Diego says they quit doing rebuilds on OEM components (considering tossing the factory suspension back on but really like the Ohlin spring rates).
I’ll dive under this weekend and have a peek at the shock mount.
Going to have to send the stock shocks off to Glen Yee (sp?) to have them rebuilt and matched to new spring rates.
Just try unhooking the end links to see if that improves the noises and check the torque on the shock mount nuts possibly?
Used parts for me have just been an absolute crapshoot. Some are a great way to save a few bucks, but most suspension related pieces I have purchased second hand have been a TOTAL bust.
Last edited by Olemiss540; 09-04-2020 at 04:58 PM.
It could be the springs. Mine does that as well (Ohlins R&T). I am thinking that when the spring gets compressed, the top and bottom of the spring twist with respect to each other.
That twisting doesn't happen smoothly. Instead, it sticks at first, then lurches when enough force is built up to overcome the static coefficient of friction.
Static friction is always higher than kinetic friction—hence the lurching and corresponding clunk.
There are thrust bearings that go over the end of the spring to fix that. Just make sure that you get the right size for your spring.
Well, I found the root of this evil. After disconnecting the drop links and heading to a local Cars&Coffee, the clunk was just getting worse.
I pulled over and removed the carpeted deck cover and leaned back and put my hand on the shock while driving. The center threaded shaft was knocking up and down; turns out the base nut was loose.
Spun home and figured out to unscrew the adjustment **** cap to reveal a slot to secure the shaft so I could tighten the nut at the base.
Well, I found the root of this evil. After disconnecting the drop links and heading to a local Cars&Coffee, the clunk was just getting worse.
I pulled over and removed the carpeted deck cover and leaned back and put my hand on the shock while driving. The center threaded shaft was knocking up and down; turns out the base nut was loose.
Spun home and figured out to unscrew the adjustment **** cap to reveal a slot to secure the shaft so I could tighten the nut at the base.
Roughly 2000km after installing my new Öhlins R&T setup my car also developed a similar sound to what TS was describing on the front left. It was especially audible on rough road surfaces like cobblestone streets. On smooth roads it was quiet and I also did not feel as if the car's handling was compromised.
I also suspected a failed top mount or maybe a nut on the suspension mounting points that worked itself loose. After a couple of hours looking for the cause we found it; my front left brake calliper was not torqued to spec, you could not move the calliper by hand but apparently when there were enough forces at play it would rattle. We tightened it up and no more noises.
I though it worth sharing as this is not the obvious place to look.
Excellent thought share, Johannvb. I have yet gotten the very slight rattle out of the FR shock...just installed a new forward link (aka 'tuning fork') thinking it was a bushing rattle but swung and missed on that one. Will check torque again on the caliper (I did R&R the fronts to install a set of Giro disc rotors...hmmmm.......).
I've been chasing down the same issue on my 997 C2S with Ohlins Road and Track coilovers. Ironically, the only one that's clunking is my right-front, just like yours. It's driving me mad. Same sound under same conditions as you describe (low speed small-medium bumps).
I've used mechanic's ears clipped all over. It really seems to be loudest when the ears are clipped to the unibody where the upper strut mount bolts to it (via the three nuts you loosen to adjust the camber). It's about equally loud when clamped to the big strut nut too. IIRC I think I even clamped one to a spring (to see if binding under compression was causing it) and it wasn't as loud, but I need to do that test again to be sure.
09-04-2020, 03:13 PM
Ohlins 'Klunk'
