777mech

Hey guys, I'm currently in the middle of replacing my front wheel bearings on the 2001 996 turbo. I was reading the pelican parts tech article on this and it mentions that some bearings have an abs or wheel speed sensor inside and they can only be installed one way and the only way to find out which side it is on is with a special detector card. Do I need to worry about this on my car or can I press them in either way? The bearings are worn and started getting loud up front. Thanks!

993GT

speed sensors tone rings are on the CV shafts, bearings are plain unitary rollers

z06801

One side of the bearing is magnetized, you can check with some steel to make sure the right side goes in first.

Carlo_Carrera

^ Very interesting.

z06801

Good diy here that talks about it.
http://www.pelicanparts.com/techarti...l_Bearings.htm

jpflip

Sorry never heard about the magnetized portion of a wheel bearing....Also I've check the repair manual for the installation of the rear bearing and no mention of this anywhere.....We got a dented wheel and a sensor on each wheel for the ABS... I went to check on my wheel bearings, front and rear, and there are no magnetized portion on them..... May be this is applicable on other model but not on 996 turbo....

Carlo_Carrera

Is it only the front bearings that have the magnetic sensor?

jpflip

No all four wheels for the abs system, see parts cat:

Carlo_Carrera

Sorry, I was not talking about the wheel speed sensor. I was talking about the bearing itself. Pelican is saying the front wheel bearing definitely has a magnet built into the wheel bearing. Does the rear wheel bearing have magnets too?

dprantl

It seems to me if a car had specially magnetized wheel bearings for ABS, it would also not have the toothed ABS rings. The 996TT has toothed ABS rings just like older cars. What would be the purpose of having both?

Dan

jpflip

Just found something about integrated ABS tone ring from the bearing company SKF.... Applicable on Porsche 2005-2012....

Carlo_Carrera

Got it. Not applicable for our cars. Thanks.

z06801

It was my friend that's been a long time tech at the dealership that showed me how one side was magnetic and needed to be closes to the sensor. One side was definitely magnetic and one wasn't. I'll ask him if he was mistaken on what years utilized the magnet.

jpflip

Yes please do, it is a bit confusing especially the repair manual , on the installation of the rear bearing page 771-772, does not mention anything about which side the bearing should be slide in the housing.....Thanks....

777mech

I went ahead and installed it so the bearing brand and part numbers are facing out. Like the guy in the 2nd post stated, it appears the only sensor is the toothed ring on the cv axle and the magnetic pickup right above it. I'm seeing so much conflicting info on this subject. The bearing does not appear be magnetic on either side.