Odd knock sound from left front.

I had new Spec B tophats, Bilstein HDs, Swifts, AVO endlinks, full Whiteline LCA bushings put in, inner and the pivot one, and the Whiteline RCK installed all professionally.

 

I'm occasionally getting a knock sound from the left front corner under braking. Not much of a feel, more noise than anything. Everything checks out and nothing looks bent, misinstalled, or broken. The car drives and handles well, just the occasional knock.

 

Any ideas on what it could be?

Please post any ideas you may have.

However, there's the strut bolt that goes through the upper mount. There's supposed to be a washer under the bolt and there isn't one. I have a spare one and I'll have that put in tomorrow morning. That's the only thing different from the driver and passenger side. Hopefully that's it and it's done.

Does turning the steering wheel from lock to lock produce the sound too? You and I have different setups, but I had a knock after installing my new struts that was from one of the springs binding up. I installed a washer in the wrong spot on one side, and it caused the strut mount to lock up and not spin freely. I don't think this is your issue if you only get the sound on braking, but if turning the wheel lock to lock does it too, we're on to something.

 

Video of my sound

http://youtu.be/tGuJMVwxDxw

 

http://legacygt.com/forums/showthread.php/do-need-tighten-my-strut-mounti-232290.html?t=232290

I thought it was the spring settling or binding in some way, but it's not doing that when I turn the wheel either way. I had the washer put in, and the popping sound went away for a day and now it's back. It's only happening during braking or acceleration. It's definitely not a sticking pad or caliper. So, that idea is out.

I had all of this suspension work done so it's got to be something along those lines.

Just to put this out there it's more like a pop sound now.

Had a similar issue and my end links needed to be tightened.

I just checked and I tightened both front endlinks. It's still happening in the conditions I described earlier. Maybe it's the spring moving around, but that's the only thing I can think of. And I don't know how it could be.

Just as an update, I took my LGT to the shop eho did the suspebsion work and they found nothing after double checking everything.

I can still hear a creaking and popping noise. The CVs check out as good.

The only thing different from the passenger and driver side are the nuts inside the top mounts. The nut on the passenger side is further down the bolt than the driver's side. Could that be it? Just a spring not tightened down far enough?

I've mentioned this in other threads, but I want to throw out the disclaimer that Im still a suspension newbie.

 

With that said, tightening down the center nut on my complete strut assembly was a little uncomfortable for me.

 

I had to use a pass through socket wrench to tighten those center nuts, while holding an Allen wrench with vise grips to keep the strut shaft from twisting. I have no idea how much I torqued down that nut, I tried a few different ways to rig up my torque wrench on it, but it just wasn't gonna work. A professional shop might have a way of torquing down that nut properly, like by holding the strut shaft by hand or with a tool, and using a torque wrench on the top nut. I didn't want to mar the strut shaft with a tool, and even though I have smaller arms and hands, I don't think I could grab the shaft through the spring.

 

Either way, I tightened those nuts down until they felt pretty snug, and I haven't had any issues. But based off what I experienced, and your description of the nuts not appearing to be threaded on equally, it does sound like that could be part of the problem.

 

What I might try doing in your shoes, jacking up the driver side of the car until the front left tire is in the air, and seeing if you can twist the spring back and forth at all.

One more quick thing. I'm not sure that this is the problem, but it doesn't hurt to eliminate it as a possibility.

 

I don't have the 2006 FSM, but I have the 2005 and 2009 ones. In the 2005 and 2009 fsm's, it says the center strut nuts should be tightened down to 41 ft/lbs.

 

I went to the bilstein web site, and it looks like your front strut part numbers are probably 35-118305, and 35-118312. If so, I've attached part of the install instructions.

 

After doing some searching, I think the oem subaru strut nuts are M12. So if the bilstein struts are the same, it sounds like the nuts should be tightened down to 34 ft/lbs.

 

So to get to my point, maybe the installer thought the nuts were M10, and undertorqued them? Not sure, just tryin to throw out some ideas.

That's exactly ehat I think it is. The tophat and nut aren't as far down as they should be. I've already had the tophat replaced once. If they take the entire assembly apart and reassemble will the locknut still be good? I'm looking for a replacement, just in case but haven't found anything.

And yes I did see the part about the locking nut being only used once. Just in case could I reuse or tighten it if I can't get a replacement?