Argeo

As mentioned, i have this annoying knock in the front left that happens usually after I’ve driven for 1/2 hr or so and after being parked.
The knock is noticeable when I’m starting to move from stand still and over bumps at low speed.
I brought to two shops. 1st said control arm and from differential (C4S) after not being able to find the 1st visit. They had also mentioned before that sometime with aftermarket parts, these knocks happen. They mentioned something about grinding something to fix. Next I took to second shop and they said everything looked good and mentioned aftermarket parts causing the issue. Said besides an annoyance, fine to drive. Both shops are Porsche Indies. Would a dealership be better at analyzing. Maybe they have a special tool others don’t?
Regarding the car, I replaced the front with h&r lowering springs, bilstein b8’s and new mounts. What part of the three would usually be the issue? Also, what parts in the front typically age and need replacing? I’m getting to the point that I just want this fixed and say replace everything which I know is not smart. When I sell this thing, I’d rather have fully sorted then with a unknown noise.

De Jeeper

https://www.fcpeuro.com/products/por...0aAvHyEALw_wcB


This, a set of drop links and replace the top mounts. This will be all the rubber in the front. Its all old and should be replaced. Aftermarket parts should not clunk. Old parts that have been removed for the new parts and put back in r probably causing the issue.

Argeo

Sorry, I forgot to mention I replaced the drop link in the spring. I had similar noise with Boxster and the drop link fixed. Not so lucky this time. Thanks for responding.
I also noticed when I Jack the car up and tire is off, I can spin the spring on its perch. I’m talking a very tiny amount but it does move. Should it?

De Jeeper

I dont know my bilstien numbers but are the b8s meant for lowering springs?

Basically at full extention u r loosing preload on the spring because of the shock length. No issue here unless u r jumping the car dukes of hazzard style.

Bottom line is if u replace all the rubber, torque all fasteners correctly and get an alignment it should be smooth and feel great. Its also a good selling point.

Argeo

Maybe I just just buy the misc pieces including and new mount for left side and have it reinstalled. I replaced the mount, some bearing and the bump stops on both sides.

Argeo

Also, would a control arm always make a noise or could it be after driving for a while and something warms up?

Corso

I have the B8/H&R combo on my C2 with no adverse noises, so the "with aftermarket parts, these knocks happen" theory can be tossed out the window.

@De Jeeper B8s are intended for use with lowering springs.

Argeo

I told the guy buying the car about the noise and what the shops said, He called his mechanic to confirm which the mechanic did.
That discussion happened before he actually tried to buy. Not sure why that underlined. Nor trying to express anything.

Argeo

Regarding my question about a control arm warming up and then making a noise, how about a strut mount? Thanks

De Jeeper

It could be any of the components. The answer is to replace all the old rubber. U may get lucky replacing one thing at a time or even find a bad part during dissasembly. Imho spend a few bucks to refresh the suspension or disclose the issue like u did and move on.

Its like replacing brake pads or a head light on one side only. It has all worn out at the same rate and it all needs refreshed.

Argeo

I wonder if it’s the steering rack. I made appointment for next week and thought maybe I could point tech in the right direction.
Anyhow, of course I drove around for a bit and was unable to hear. I went over bumps with power and just rolling, nothing.
I did notice that when I turn the wheel stopped all the way either way, I get a similar knock.
Not having anything to compare to is tough. Maybe they all knock.

hardtailer

It's generally difficult to identify the components that cause the noise. It's either through direct experience when someone recognises the noise and knows what it is caused by because he remembers it being gone after replacement of the offending part or through using diagnostic equipment like piezo transducers that are stuck to parts that possibly cause the noise and then listen to each channel/transducer at a time and pinpoint the offending part by means of it causing the loudest signal.