997 C4S front wheel shake at 3 & 9 o'clock
08-09-2021, 10:53 AM
#1
Rennlist Member
Thread Starter
997 C4S front wheel shake at 3 & 9 o'clock
I have an 09 C4S with ~60K miles. I recently noticed the front end occasionally "grabbing" seems in the road and assertively drifting. Now that is compounded by a front end shake when braking. I jacked up the front end for inspection:
1. No visible issues, although there is some fluid film in the vicinity of the steering rack (10+ year old car)
2. No play in the wheel when grabbed at 12-6 o'clock.
3. 1/4" or more play when grabbed at 3-9 o'clock, with audible click/knocking.
4. I swapped out both full tie rods (inner/outer, both sides)
5. Still have the lateral play at 3-9 o'clock.
6. No wheel spacers, OEM wheels (have rotated orientation, swapped sides, etc.), almost new brakes.
So, I'm going to lift the front end and get underneath to watch while a buddy grabs and moves the wheels to induce the play.
1. What should I be looking at to find the culprit?
2. What are the other likely culprits?
Thanks,
Purple
1. No visible issues, although there is some fluid film in the vicinity of the steering rack (10+ year old car)
2. No play in the wheel when grabbed at 12-6 o'clock.
3. 1/4" or more play when grabbed at 3-9 o'clock, with audible click/knocking.
4. I swapped out both full tie rods (inner/outer, both sides)
5. Still have the lateral play at 3-9 o'clock.
6. No wheel spacers, OEM wheels (have rotated orientation, swapped sides, etc.), almost new brakes.
So, I'm going to lift the front end and get underneath to watch while a buddy grabs and moves the wheels to induce the play.
1. What should I be looking at to find the culprit?
2. What are the other likely culprits?
Thanks,
Purple
08-09-2021, 11:03 AM
#2
Rennlist Member
1/4" or more play when grabbed at 3-9 o'clock, with audible click/knocking. ... which wheel
Wheel bearings would be at the top of my list if it is one side
Steering linkages (track rod (tie rods that you replaced), loose or worn joint on the intermediate steering shaft) if both sides feel the same.
Wheel bearings would be at the top of my list if it is one side
Steering linkages (track rod (tie rods that you replaced), loose or worn joint on the intermediate steering shaft) if both sides feel the same.
Last edited by CAVU; 08-09-2021 at 11:13 AM.
08-09-2021, 11:07 AM
#3
Rennlist Member
Front differential possibly?
08-09-2021, 11:38 AM
#4
Racer
Join Date: Jun 2018
Location: Cairns, North Queensland, Australia
Posts: 426
Received 181 Likes
on
105 Posts
As in something has failed inside front diff and momentarily locking the front axle, this side or that, random and unexpectedly?
Could be a thing, I had a Dana diff fail (in a different beast altogether), the lock for the star gear shafts allowed the star gear shafts drift in and out of the diff centre, they would touch the housing or something. I got to experience a huge clunk/clank, then it would be OK for a few more miles.
Could be a thing, I had a Dana diff fail (in a different beast altogether), the lock for the star gear shafts allowed the star gear shafts drift in and out of the diff centre, they would touch the housing or something. I got to experience a huge clunk/clank, then it would be OK for a few more miles.
08-09-2021, 12:17 PM
#5
Rennlist Member
I had bearing failing inside my 996 4s front differential.. Mechanic noticed a small leak after I complained of vibrations and whining sounds when off throttle. Just throwing out the idea, not sure of all the possible ways a failing diff will present itself.
08-09-2021, 07:23 PM
#6
Rennlist Member
Failing wheel bearings should cause s-s and t-b movement not just s-s and they would be noisy as hell if they were that far gone. I would have someone look at the other wheel when you move one to see if it's just one side or just one side moves at a time. If both sides move together, it could be the steering rack or rack mounting bushings if Porsche uses those. 1/4" is a lot of movement. All that said, if you're not going to wrench on it yourself, just take it to an alignment shop.
