Pulls to the right Pulls to the left

Lyso · 05:45 AM

I just purchased (a few months ago) a 2001 996 Carrera cabriolet with 64K. I have what I think is a problem with the car pulling sharply when breaking to one side or the other. If I stop at high speed or slowing down at a light with the steering wheel straight on the car it brakes perfectly straight. (I do this with my hands off the steering wheel to test although I can feel it with hands on). If I turn the wheel slightly to the left or right and break (as if I am preparing to turn) the steering wheel and car pulls sharply to the side that the steering wheel is slightly turned toward. I have never had this problem on all my other cars where the wheel tends to pull the car straight or very little pull even with the slight wheel turned. My other cars did not have as flat of a profile or as wide a tire as the 996. Will a positive toe cause the braking to pull like this? I have tried this on different roads and it is not dependent on road profile.
The car has:
New tires and good brakes pads and rotors. I have cleaned and rebuilt the front calipers (did not seem to have any corrosion) and bled system but this did not affect the problem. The suspension seems tight and all wheels do not have any drag on them when spun by hand. I can’t feel any play in the steering rack.

I don’t want to just play the parts replacement game without some idea if this is a real problem or a characteristic of wide flat profile tires unlike what I am use to.

Some have suggested:
Wheel alignment although the old tires did not show uneven ware.
Just replace front calipers, rotors and pads and soft brake lines.
Replace powers steering pump or rack.
ABS or PSM system faulty (ABS seems to work properly when engaged) and have same problem with PSM turned off.

Am I just not use to the wide flat tires? Again if the steering wheel is straight no pull at all with your hands off the wheel with a slight bias to the wheel car pulls sharply and dramatically to the side bias to wheel direction.
Am I just chasing a normal condition of wide flat profile tires?

BYprodriver · BYprodriver's Garage

Castor is designed for directional stability. Some alignment shops do not adjust camber as a shortcut because it rarely contributes to tire wear. I believe since you have new tires & alignment there is a good chance the camber is off. I always get a before & after printout of alignment settings before & after.

Jeff Alton · 05-07-2019, 10:14 PM

I think you mean Castor. Can't be adjusted on a 996 without the purchase of aftermarket arms.

I would start with a trip to your favorite independent shop. Have a tech go for a drive with you to see and agree on the symptoms. My thoughts from reading your post is that your car needs an alignment. One other questions, does it have the same behaviour if you floor the throttle with your hands off the wheel?

Cheers

racer · 05-08-2019, 04:52 AM

I wonder if its a ball joint/control arm issue. Its an 18 year old car. Rubber parts shouldn't last that long. Toe wouldn't cause it. The larger low profile tires aren't causing it. To me, its a mechanical issue.

BYprodriver · BYprodriver's Garage

Quote:

Originally Posted by Jeff Alton;10451992[B

]I think you mean Castor.[/B] Can't be adjusted on a 996 without the purchase of aftermarket arms.

I would start with a trip to your favorite independent shop. Have a tech go for a drive with you to see and agree on the symptoms. My thoughts from reading your post is that your car needs an alignment. One other questions, does it have the same behaviour if you floor the throttle with your hands off the wheel?

Cheers

Yes I did mean Castor, thanks.

Lyso · 05-09-2019, 12:55 PM

I tried to accelerate in first and at higher speeds with no hands and it does not behave anywhere as dramatic as when you brake hard with no hands. And when the wheel is straight it goes perfectly straight. When I got the inspection we checked suspension but I will take a second look at ball joints and then try an alignment. With no hands at slow speed it spins the steering wheel to the right or left when coming to a stop but not when straight on. It is also very sensitive to road profile like road grooves.