Jedi767

I've got a 2003 996TT that is so incredibly sorted it's insane. Everything about how this car drives is perfect except a high speed wheel shake / wobble (really feel it at 75mph and it increases as I speed up - gets pretty severe).

I can't be positive, but it's definitely felt in the steering wheel and the front floor. This shake makes me pretty depressed about the car and honestly stops me from driving it as much as I'd like. It's been to 3 different shops since exhibiting the wobble, all the shops say everything is perfect.

I've recently moved into a home (finally) and have a jack so I can take a look myself, though I'd need to know exactly what I'm looking for since I'm not very mechanically inclined. Any help is seriously appreciated here.

HERE is what has been done on the car that would effect (or eliminate) the possibility of front wheel shake:

• H&R Front & Rear Sways + End-Links (came on car when purchased 2 years ago)
• Bilstein PSS10s (came on car when purchased 2 years ago)
• Rear Wheel Drive Conversion
• Front Brake Discs + Pads
• Front Wheel Bearings
• New Porsche Sport Techno OEM Wheels (shook before this, still shakes with new perfect wheels + tires)
• Semi-Solid Engine Mounts - Tarrett (1 shop said thats why the car feels rough at high speed, I don't buy it)
• Front Monoball Camber Plates - Tarrett
• GT3 Front Lower Control Arms
• GMG Thrust Arm Bushings
• Outer Tie Rod Ends
• Several sets of new tires (currently on Yokohama A052s), many rebalancing services, alignments, etc - never fixing the issue.

My current alignment:

2fcknfst

Bent wheel, out of balance wheel, or bearing on its way is my bet.

Jedi767

Wheels are new, bearings are new, and the balance has been done multiple times.

Wobble was there before & after all ^.

2fcknfst

Then you have to go deeper - was the car ever in an accident?

2fcknfst

Could also be a rubber bushing that has given up, but looks ok from the outside.

Jedi767

Perfect CarFax, and never any signs of damage or accident in all the extensive work we've done.

blockhed

Just because Carfax is clean means nothing. I'd start checking all the control arms, links and bushings at 75 it's suspension and car ain't happy.

Jedi767

Multiple reputable shops have 'gone through everything' looking for the cause of this issue / replacing the parts I listed out. GMG, Pacific German, Stuttcar, MiniCorsa, etc.

Considering the only parts that have been on the car since I bought it are the PSS10s + H&R Sways, is it possible something there is off (and going to be visible to a normie like me if I pull a wheel off)?

s65e90

Check nut behind wheel

Carlo_Carrera

You say the car has been converted to rear wheel drive, correct?

If that is so check the stub axles or whatever was use to replace the front drive shafts. Your wobble is probably from those parts.

2fcknfst

This, for sure - anything could have happened and been repaired without insurance.

This is an interesting idea, does the hub spin?

Looking at the rennlline stubs, my thought is no, but the possibility of a weight imbalance, and then a problem with a shock could most certainly induce a vibration.

Jedi767

Yes RWD conversion (as all Turbos should be IMO). No additional parts were added as they are not needed.

Regardless - the wobble was there before the RWD conversion.

Jedi767

I could get it up on jack stands now and investigate / take images - but I'd need some guidance as to what I'm looking for.

Carlo_Carrera

If that is the case the only thing I think of is that the steering rack is shot/damaged.

Jedi767

Ooooh - interesting idea.

Is there anything I can do at-home to check its condition?