steering rack
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From: The Nook
+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
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
RL Community Team
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Joined: Jul 2004
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From: Dallas, TX
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
Andy
Pro
Joined: Mar 2020
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From: London
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:
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:
Intermediate
Joined: Oct 2017
Posts: 29
Likes: 6
From: SF Bay Area
I was cleaning the cabin filters and I could see some pooled oil way down on the front underside cover. It appears that the steering rack has been leaking. Haven't taken the cover off for an inspection yet but I'm thinking that the rack is leaking......a known issue. If I have to r & r it for examination/replacement, can anybody offer some caveats to the job? Any hidden jobs?
I did a google search and have downloaded the instructions from Pelican Pars and it all looks pretty straightforward. Any and all help much appreciated.
JC 99 TT
I did a google search and have downloaded the instructions from Pelican Pars and it all looks pretty straightforward. Any and all help much appreciated.
JC 99 TT
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!
RL Community Team
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From: Dallas, TX
I would think a shop has already looked at the ball joints and the A-arm-frame but who knows.
Andy
Racer
Joined: Sep 2006
Posts: 451
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From: Indiana
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:
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:
Pro
Joined: Mar 2020
Posts: 662
Likes: 178
From: London
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.
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.
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RL Community Team
Rennlist Member
Rennlist Member
Joined: Jul 2004
Posts: 10,602
Likes: 2,049
From: Dallas, TX
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
Last edited by pp000830; Oct 2, 2020 at 01:30 PM.
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From: Minneapolis
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.
Technical Guru
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From: USVI
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...
Originally Posted by nk993
here is a slight knocking sound when initially turning the steering wheel left.
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?
Last edited by JasonAndreas; Oct 9, 2020 at 01:01 PM.