So, for the first time in the 2+ years I've owned my car, I have an actual mechanical problem.

Today I ran an errand and noticed a clunk/thud noise coming from the right rear suspension while going over bumps, potholes, manhole covers, etc.

It's pretty loud and noticeable. And sensitive -- even going slowly, it's loud, sort of a sharp thud, if that makes any sense. I stuck my head under the car and couldn't find anything visibly wrong -- the suspension components, sway bar mounting points, collars on the coilovers, etc, all look perfect. The ride height is unchanged. I checked the engine mounts as well, which are Wevo's, and they're fine.

My car has PSS9's that the PO installed four years/25K ago. I suspect that this is a blown shock, or something like that. Anything else would be visually noticeable, right?

 

Noah,

Take a hard look and check the nuts holding the rear rubber shock mounts in the car as well as the top nut on the shock shaft. Further, check the torque on the upper and lower control arms as well as the lower shock bolts.

Providing that everything else checks out, you may need to pull that RR shock to see if its blown. If thats the case, send it to Bilstein along with a copy of the sales invoice (needed for a warranty repair) and they will rebuild/repair it for you.

 

Steve -- thanks much, will do! I'll update this thread tomorrow. I hope it's something simple.

 

Great advice from Steve as usual.

Also, check your rear ARB drop links, make sure they are tight.

 

Thanks, I'll do that too. All I did was look at everything -- no wiggling of parts involved.

 

Noah,
Unless you've already done so, get the car on stands to see everything with the suspension at full droop. By your description, it seems like something that should be easily identified.


Andreas

 

I really doubt it's a blown shock judging by the noise you described. I'd suspect a rotating drop link; very common on PSS9's. Might look ok, but you'll need to remove the wheels and look for signs of rubbing. They can rotate and hit the drive shaft, suspension arms, subframe, etc.

 

Okay, well I think I've found a major clue.

On the top of the right shock, inside the engine compartment, the big cad-plated washer that sits between the retainer nut and the rubber grommet can almost be spun 360 degrees. It's that loose.

Now this either means that this large retainer nut -- it looks like a nylock 19mm -- has somehow backed itself off, or that something else is going on. What's the protocol here? Do I just crank down on that nut and see if things tighten up, or is there a better, more precise way to figure out what's going on here?

 

Just to make things clearer, here's a pic of my car, with a big red arrow pointing to the loose washer.

Bonus question: other than the air filter cover, which I removed to gain access to the top of the shock, can anyone tell me what's strange about this picture?

 

I think that should work. I forget with PSS9s... can you hold the shaft from rotating using an allen/torx wrench on the end? Otherwise the entire shaft will spin, and you don't really want that. If no, you could use an air rachet with 90-degree fitting. Using a simple deep socket on a wrench will probably just spin the shaft.

I'd suggest getting a locknut to back up this nut. Got mine from www.boltdepot.com.

 

power steering pump is gone?

 

it will be a two handed type of tightening sequence. You have to hold the shaft and tighten the nut at the same time.

 

Is this like the Bilsteins in the old t-bar 911's, where you tighten the retainer nut while holding the shock shaft with an allen wrench (e.g. everything is done from inside the engine bay), or do I need to get the car on a lift, take the wheel off, and have one person under the car holding the shock body while I tighten the nut?

 

Noah,

There's actually a special tool that allows you to hold the shaft stationary with a hex wrench while tightening the nut... But, the backyard mechanic in me would tell you that you can get by by taking a socket of the proper size and clamping it firmly in a pair of vice grips, then reach thru the 3/8 or 1/2" square hole normally occupied by the socket wrench and tighten firmly. You may even want to grind a couple of flats on the top of the socket to allow the vice grips to really get hold. You can actually get more torque by using thehex wrench to do the tightening and just holding the nut stationary, but you don't want to spin the shaft of the strut... only use the hex wrench once you have it relatively tight by turning the nut on top.

I know that may make some of our actual mechanic members cringe, but I promise it will work. One thing to note however, my experience is that the nylon locknuts rarely loosen unless they have been removed and reused... You're only supposed to use them once then replace. So, you might consider a new nut... or at least a bit of locktite.

 

^^^^----Do like he says. It won't help to have a guy underneath trying to keep the piston from spinning, because you can't get a grip on a perfectly round oiled bar!