Front Suspension Noise Over Bumps

tyro · 06-06-2012, 07:57 AM

Picked up a set of Bilstein HD inserts for my Boge housings last year. Ever since the replacement of the Koni reds which were installed, I get a nice clunk/clank over sharp bumps in the road surface on the passenger side of the car.

I have checked into the following:

-The gland nut is as tight as I could get it with a couple of 10" pipe wrenches.

-The ball joint is good, cannot get movement with a set of channel locks.

-The strut top nut is tight.

-Last night I removed the metal "dust cover" as it seemed that it was possible that it could make the noise, no dice.

-The rubber ARB bushings on that side look like they could be replaced, but don't seem to be the culprit.

-I've also thought that maybe the a-arm bushings are toast - difficult to tell but the front of the a-arm bushing is centered.

-I have not replaced the rubber shock mount on either side of the car.

What are the chances that I have a bad strut cartridge? I'm probably going to put the Konis back in tonight because the noise is a bit annoying - and it will be a good test.

Any thoughts suggestions ideas are welcome, thanks.

bkreigsr · 06-06-2012, 08:20 AM

Did you check the extended length side-by-side HD vs Koni. If they sent you Sports by mistake, they are shorter and could be bottoming (topping) out internally when you go over a bump. Bill K

tyro · 06-06-2012, 09:02 AM

I'll check, but the noise is only apparent on the passenger side of the car.

Next plan is to swap left and right side inserts. Might get to that tonight.

Thanks!

Bob Kontak · Bob Kontak's Garage

You probably did this but jack up the car and get the wheel off the ground and reef by hand on the tire to try to replicate the noise.

Chuck Moreland · 06-06-2012, 07:44 PM

For some boge struts, the bilstein inserts require a spacer to be installed in the base of the strut housing. In the absence of the spacer, the insert is a bit too short to be pinched down by the gland nut.

If you need the spacer and omit it, the insert can move up and down inside the struts perhaps .25 inches. The solution is to add a spacer to the base of the strut.

targa44 · 06-06-2012, 11:59 PM

One other thought that's probably too convenient for coincidence - that the old right side shock was toast and the new one created tension in the drop links rod ends...

.... maybe you can test by pushing up on the right side A/R bar and get the link to "pop"?

porterdog · 06-07-2012, 05:23 AM

I had a set of Bilsteins on a VW once that had a similar sounding issue and it *was* a bad insert...

gregwils · gregwils's Garage

Quote:

Originally Posted by Chuck Moreland

For some boge struts, the bilstein inserts require a spacer to be installed in the base of the strut housing. In the absence of the spacer, the insert is a bit too short to be pinched down by the gland nut.

If you need the spacer and omit it, the insert can move up and down inside the struts perhaps .25 inches. The solution is to add a spacer to the base of the strut.

+1. I actually had this issue with a boge insert in a boge strut, you could see side to side movement of the insert inside the strut. Had something similar with an old Audi 5000TQ, inserts actually came with spacers. The movement is probably side to side or vertical - up/down.

tyro · 07-02-2012, 07:43 AM

Back again, had some time to work on the car over the past couple of weeks.

I have replaced the shock mounts and the front/rear ARB bushings.

I have not swapped the shocks from side to side.

The inserts are in the housings nice and tight, no play at all.

Still a clank over the "sharp" bumps but I'm not sure where it's coming from now. Sounds like down low in the center of the car. Starting to wonder if I should empty out the front of the car and look for a large wrench hidden in there..

Just curious - what do bad a-arm bushings sound like? Do they have a sound?

Thanks.

bkreigsr · 07-02-2012, 08:11 AM

You can do a visual on the a arm bushings.
When new, there is an equal amount of space around the circumference of the races and retainers.
If it looks like there is contact on the upper surface - (no visible space/gap) it's time for replacement.
Still, even if they are rubbing metal-to-metal, it's usually not the 'klunking' sound you describe. - I'd keep looking at the struts.
Bill K

roger's 2937 · 07-02-2012, 08:44 AM

Do the roll pins in the bottom of the assembly have a good tight fit??

aj88cab · aj88cab's Garage

Lot's of good ideas above...I'll add one more. Did you lower your car? When was the last time you had the corner balance checked? Did you check the CB after changing the shocks. If the height adjusting bolt has backed out or was not adjusted correctly the passenger suspension could be "light" and the adjusting bolt will bounce off the bracket over bumps and clunk. It was the issue with a similar clunking noise I had.

ant7 · ant7's Garage

Quote:

Originally Posted by tyro

Back again, had some time to work on the car over the past couple of weeks.

I have replaced the shock mounts and the front/rear ARB bushings.

I have not swapped the shocks from side to side.

The inserts are in the housings nice and tight, no play at all.

Still a clank over the "sharp" bumps but I'm not sure where it's coming from now. Sounds like down low in the center of the car. Starting to wonder if I should empty out the front of the car and look for a large wrench hidden in there..

Just curious - what do bad a-arm bushings sound like? Do they have a sound?

Thanks.

hi Jess,
i had a similar noise on my previous 911, i found that when the car was on its wheels, if you shook the car side to side [holding onto the gutter rail] you could feel play in the front suspension, however, when it was jacked up there was no play to be found in anything.
Worth a try.

Anthony.

Joeaksa · 01-26-2013, 08:20 AM

Quote:

Originally Posted by Chuck Moreland

For some boge struts, the bilstein inserts require a spacer to be installed in the base of the strut housing. In the absence of the spacer, the insert is a bit too short to be pinched down by the gland nut.

If you need the spacer and omit it, the insert can move up and down inside the struts perhaps .25 inches. The solution is to add a spacer to the base of the strut.

Chuck is spot on here. I have put up with this for over 10 years from when I replaced the stock shocks with Bilsteins. Love the shocks but always getting some noise from the front end on bumps.

Just overhauled the entire suspension this past week and found about a 2mm gap in the shocks in the strut housing. One small washer in the bottom cured this and now the front suspension is tight and quiet!

Thanks Chuck!