Knocking from top of steering column - Any solution?

Guys I have a knocking noise that is coming from the top of my steering column, sounds like it's right behind the steering wheel. It happens as i turn the wheel slightly left and right from the centered position. I had a similar noise on my old 911SC and had to change the upper bushing on the column. It appears on the 996 the steering column is not serviceable? Anyone have this and is there any solution other than replacing the entire steering column with a new one? Thanks in advance.

I had a similar situation in a Boxster, you would swear the noise was coming from the column, but in my case it was the suspension arms on the front that connect to the lower control arms. When the car is on the hoist they appear to be tight because the suspension is unloaded but the play is revealed when there is weight on the wheels.

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Yeah I'd hate to do the major dash surgery to replace the column ($1200 for a new one) then find it still makes the noise. My entire front suspension is new, I replaced all bushings, new tuning fork arms, and installed coilovers w/ monoball tops this winter. I will go thru and re-torque everything. I have read about steering knocking being from the inner tie rods on the steering rack but man it sure sounds like it's coming from right behind the steering wheel.

Ok so I am still fighting this issue. I replaced the inner and outer tie rods with new TRW parts. The noise is still there. I removed the steering wheel and the bezel around the steering wheel stalk. I have hunted all over under the dash with a mechanic's stethoscope and the noise is difficult to isolate. I do think I hear it loudest near the splines by the clutch and brake pedal. It echos so much through the entire column it's tough to really nail down. It appears the remaining parts of the steering are the column and the rack and that's about it. Both are expensive (and the column looks like a nightmare to replace) so it would be nice to isolate this issue before I start buying parts. Anyone have any suggestions on what else to check or how to try and isolate the location of this?

I had a similar issue, ended up being the 'tuning fork' arms, you cant visually see any damage to them. See number 3

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Thanks for the idea, but my tuning fork arms are brand new! Right now I am thinking it's somewhere in the lower steering shaft (ironically called the "intermediate shaft" in the parts catalog), or in the rack itself. I will get the car upon the lift and explore further this weekend.

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Ahh awesome so rule that out! There are actually inner tie rod arms on the inside, perhaps it's those?

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How about your upper strut bearings? Put the stethoscope on the nut on the top of the strut and have someone make the noise. I have also seen noises when the plastic coating on the splines cracks. When turning it will stick for a split second and cause a pop but usually you cant hear that, you just feel it in the wheel when turning. The upper strut bearings make a pop sound. EDIT: Wait I just reread your post. This is probably related to your coil overs. You can try a teflon based lubricant for the monoballs on the upper strut bearing.

You might want to check out this thread. It has some information and a link to a RennTech thread on the steering column issues https://rennlist.com/forums/996-foru...ing-wheel.html

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Inner tie rods are brand new, replaced 2 weeks ago w/ the outers too. Thanks for the suggestion though. I will take a look at the monoball tops, that seems like a long way for the noise to travel but it's possible. Thanks! Thanks, good pics there. I tore apart the upper column already and did not find anything. Crazy how it sounds like it's right behind the wheel but then I can't hear it there w/ the stethoscope. Thanks for the link.

Did some more investigating with the car up on the lift and my wife in the drivers seat turning the wheel, searching around with my mechanic's stethoscope. The noise appears to be coming from the rubber coupling in the lower steering shaft. Everything looks to be intact (as in I don't think any thing is dangerous here) but the two large rivets that go through the rubber coupling appear to pop very loudly under back and forth load. There is no perceptible movement but the noise is definitely loudest there w/ the stethoscope. There is also a little noise from the steering rack itself but that is not noticeable in the passenger's compartment and I would think once it's getting hydraulic assist with the car running it may not be noticeable at all. Fortunately it appears that for a PSM equipped 2003 I can purchase the lower steering shaft as an individual part. For earlier and non-PSM cars it appears this part is only sold together with the entire steering column. Here we go!

Actually looking at it further the entire piece is available for PSM cars including the upper and lower U-joint which are both held to the steering column and the steering rack respectively with splines and a pinch bolt (#36 in the diagram below). The non-PSM cars appear to have the upper u-joint as a non-removable part of the steering column. I suppose if you had a non-PSM car and you needed to just replace the lower u-joint you could purchase the PSM part, remove the lower half of it (they are connected in the middle by sliding splines for the adjustable fore/aft steering wheel), then discard the upper part.

**PROBLEM FIXED!!!!** Hey guys just wanted to followup in case anyone else ever has this issue. I removed the steering u-joint shaft today and was able to confirm the knock was coming from the rivets at the rubber coupling (See video below). I installed a new shaft and the problem is solved!!! You Tube Here's a photo of the old and new shaft side by side:

How odd! Well done on finding it

Good catch! How much $ did that part run you?

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About $500 and had to wait for it to come from Germany b/c it's no longer stocked in Porsche's USA warehouses....which was surprising to me since it appears the same part was used on the Boxster, Cayman, and 997.

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Cool! That's not all that bad... I'm sure they can be had for a lot less from a dismantler as well

Apologies for resurrecting an old thread. Has anyone else experienced and confirmed, as this does not appear to be a common finding. If it's the rivets, can they be replaced with new rivets/fasteners/bolts ?

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great work!

Responding to an old thread, want to thank @Nickshu for excellent work and for helping me with a similar issue. I am still experiencing this "ghost knock" after replacing the lower shaft - which my Porsche-trained part time indy mechanic now hates me for (just kidding but he said he never wanted to do it again). He is also mystified and really wants to fix it but we're unsure what to try next. I took the car to another well-trusted pro Indy and he says it's in the steering column itself, and says it needs replacement. This will not be cheap, likely well over $3k (part cost is Like $2700 retail). I'm about to post an inquiry to see if any help is out there but starting here for any potential help from continuity among readers of this one. Has anyone replaced their steering column? If so I'd love to learn from your experience.

Great job and persistence in solving the problem. I thought it might have been a loose nut behind the wheel. Iol ​​​​​​​

Typical Porsche, on most cars those rivets are bolts, so you can replace the rubber in the rag joint.. for about 10 bucks.. I bet its a rubber out of a 69 VW transporter van.. LOL