alsamrob4

+1
love reading Andy's blog. It reinforces and makes me feel so much better about paying the mechanic for work I wish I could do, but don't have the skill to do. Makes me a much more knowledgeable consumer. Never noticed the donate button

pp000830

Be aware the later 993 rack is unique in its function and internal parts. Other racks may look similar or even fit in the application but do not perform in exactly the same way. This is why one should always record the serial number on their rack and send theirs in for a rebuild, not a swop. Also, a rack made from a substandard core will result in a rack with a short service life. 993 cores are a bit of unobtanium for rack builders as they are unique to a 993 and most 993 are still on the road so the quality of the cores can be varied at times. These are the reasons why I would never swap racks with on in a rebuilder's inventory.
Andy

nk993

While we are on the subject of steering racks, I have a slight issue with mine that nobody has been able to diagnose/fix. There is a slight knocking sound when initially turning the steering wheel left. When I hear that knocking sound I also feel a small knock underneath my left foot. (I am a RHD car, so my left foot would be close to the gearbox tunnel). I had the suspension checked over and there was no interference anywhere. While recreating that sound, they did say they can see the power steering line in the central tunnel (underneath my foot) move a bit when the knocking sound is made.

I had another shop strap the line down, allegedly. The knock and the bump underneath my foot are still there (although i can feel a bit less with my foot, presumably because the line is moving less). So I assume the line movement is just a symptom and not the issue. Any ideas what could be causing it? I flushed the power steering fluid, but it had no effect. Also the old fluid was not that dirty/black.

Here is a video of the sound:

PorschePeter

I attempted to re-build my rack with a new seal kit, but at the very last step I ended up stripping the nut that compresses the spring to the shaft. After a long cussing session and throwing tools across the garage, I ended up sending it out to Advantage Steering in Indio,CA. Well worth the 650 bucks to get it cleaned, re-sealed, rack shaft polished, and tested. Cost also includes two way shipping depending on where you're located. Highly recommended them to save you time and any headaches that you may encounter. Especially that darn C-clip to remove the shaft.

Although a great learning experience to rebuild the rack, if I had to do it again, I'd send it out for refurb in a heartbeat. Good luck!

pp000830

Worn or loose joint, worn bushing or bad strut or strut hat. Park the car on level ground grasp each front tire and jerk it left and right and see if it moves or makes a noise. Have someone listen under the car using a short length of garden hose as a stethoscope as you move the steering wheel to the left and right triggering the sound to localize the sound source.

I would think a shop has already looked at the ball joints and the A-arm-frame but who knows.
Andy

drodg

I have a very similar noise but it is at low speeds on small dips in the road or uneven road services. I was told by one shop the gas tank can start making noise as the mounts etc on the tank start eroding with age? So weird never heard that before.

nk993

thanks Andy. One of the best suspension tuners in the UK spent around an hour underneath the car to try to diagnose the issue and they found nothing. All the joints are new too. I was with them underneath car, couldn’t see anything either. But who knows. The hydraulic line jerking does make it sound like the steering is hitting something and the pressure is going up.

that’s very interesting. Your description is mine exactly (low speeds and dips). I’m not sure why the gas tank would cause the power steering hydraulic line to jerk though.

JasonAndreas

This problem has absolutely nothing to do with your suspension... What model year do you have? And what size are your tires?

nk993

1997 C2S. 235/40R18 and 285/30R18. Cup 2s

pp000830

Hi Jason,
Are you thinking the bushing in the steering column? My previous 930 had this issue as the plastic bushing failed. I replaced it with the metal one with a 928 part number to resolve the issue.

Or the reinforcing strut upgrade for the rack mount when going to larger rims?

Enquiring minds want to know.

Andy

nk993

Hi Jason. Any update on what you think this is?

PRSWILL

Another KUDO for Andy- never met the guy, but he definitely knows what's going on with 993's. I've read and taken a TON of advice from him. never seen the blog- so i've never donated- but I think there's at least a few people here that would be happy to contribute to Andy to keep the knowledge faucet wide open.

JasonAndreas

Quote:

Originally Posted by nk993

they did say they can see the power steering line in the central tunnel (underneath my foot) move a bit when the knocking sound is made

Did they replace those mounts?

The conversation over here was going down the blackhole path of "its the suspension" guesswork, so I was hoping to knudge you back out. There's no magic bullet for power steering issues, you have to trouble-shoot them on the spot. That said, if the problem just recently started to occur without any additional work having been performed on the car, then it could be the rubber (964-347-137-07) under the holding clamps. If the rack moves even tiny infinitesimal amount, the lines can move. The problem could also be made worse by having 18" wheels and not having the steering rack cross strut (993.347.131.02) installed. Preventing the rack from moving/twisting and the lines from knocking was its sole purpose. It had nothing to do with "improving steering feeling". Porsche tried everything to resolve steering noises, including switching from a piston to a rotary valve rack and they still couldn't fix it. Until they cheated with the brace.

If the lines weren't knocking, I would have suggested looking at the ball bearings at the base of the steering tube (not the shaft)

The problem is, we are guessing...


Does it make the same clicking sound as in the video with engine RPMs at 2K? If you hold the wheel all the way to the right or left for 10 seconds with the engine at idle, does it click?