I track my car a lot and had developed bad brake vibrations that no one could figure out until I finally replaced bearings and hubs. Now their are no vibrations or shudder and the brakes are rock solid on the track. I kept blaming rotors for the longest time and turned out to be bad bearings.

 

Wheel will fly off.........lol.......

Actually the bearing would probably blow apart and the wheel would start flopping around held in by the axel until the entire mess came apart.

The hard part is that you need to remove the brakes and unhook your axel to see/feel if they are really bad. I noticed no deflection at all in the rears, just the slightest rough feel when rotated,and yet when taken apart they were absoloute TRASH. If they are making any noise at all,change them. The new bearings had a different (maybe improved) seal. I believe the failure is mostly due to dirt/water/dust contaminating the bearing. The bearing itself is a hell for stout design, but if any crap gets in there it's going to start to go. I think I will check them every 20K from now on.

 

My 996 c4s had it at 49k miles.

 

Did you upgrade to something other than OEM bearings?

 

As far as I know there is no upgrade, just a slight change from 2001 till now, the old bearings had rubber/delrin seals. the new had a steel/rubber seal on one side,I assume to hold up better when dust,rocks etc hit it. It could also just be a manufacturing change over the years, who knows ???

 

So is there a chance any of the later model 996 TT's have the newer bearings? And has anyone checked the lifespan of the newer bearings vs the old?

And lastly, of all the 996 TT's has there ever been a catastophic bearing failure?


I think these are the most pressing questions than to have everyone running amuck looking for bad bearings.

 

How would you describe the sound that is supposedly symptomatic? I've been hearing some strange noises lately, wondering if this could be it... Hoping my ears are just playing tricks on me, though.

 

The best I can describe it is that it sounds just like tire/road noise inside the car.
Go to deserted parking lot, speed up to 30-40 or so, pop in neutral and kill the motor, do a "S" turn back and forth, if noise goes away/changes they are most likely shot. The noise should change when you load/unload the bearing.

 

Hmmm.... I've been blaming my tires (and roads, and anything else) for the deafening noise inside my cabin. I guess I'll be doing some parking lot tests now!

 

I thought my wifes brakes were bad once and started taking the thing apart. Once I got the caliper off the rotor fell on the ground because the bearing had completly fallen apart.

Even though your car only has 20k miles just remember that it is hard on moving parts to sit for extended periods of time, your car is still 6 years old.

 

What is the life expectancy range for wheel bearings on the Turbo?