ABS gone crazy after wheel bearing replace

[barryb97]

2001 115k miles. I replaced the left front wheel bearing and while I was in I replaced fwd control arms, ball joints and brake lines. I cleaned everything up bleed the brakes and off I go on my merry way. After a short drive all of a sudden I get ABS and brake lights on the dash but it seems to drive fine. After stopping and restarting the ABS or DCS system kicks in and is trying to brake and cut the throttle. I did some searching on the forums and I figure it must be the ABS pulse generator that I removed and reinstalled. I replace that and it does the same thing! I pulled fuse 51 and it seems like it is now at least drivable.

After more forum searching it sounds like it could be:
- ABS modulator. But what does that have to do with changing a wheel bearing?
- Steering angle sensor.
- Alignment. I didn't touch the tie rod ends and it dives true and straight.

What do I do now? I hate taking my car to the shop but I don't have any way to diagnose this one.

Any suggestions from you with more experience?

Thanks

[nas517]

The wheel bearing has a sensor on it. Did u use a original or oem quality wheel bearing.
It's not really a sensor but it what tells the speed sensor how fast ur wheels is going.
Who pressed in ur wheel bearing. They could have damaged the round black thing with notches that sends the wheel sensor ur speed. I am a hundrend percent positive that's whats wrong. Alot of people think that it's is on the axles as in most cars it is. So u need another wheel bearing and make sure it's not damaged when it pressed in. Or it could be a wheel sensor that went bad. Or damaged. I had the same issue an I replace alot of parts and figured that out the hard way.

[barryb97]

All BMW OEM parts. I pressed the bearing in myself. I know it is in the correct direction. But it took a huge amount of force to get it installed. I already replaced the sensor. I pulled the fuse so it is at least drivable. Before I throw more parts at it I think I'll take it to a shop that has a tool that can read the ABS codes and make sure what the problem is.

Thanks for the input.

[barryb97]

UPDATE. nas517 you were exactly right. I took it to a reputable independent mechanic and they confirmed that the bearing was damaged. I talked to the mechanic and he said it is very critical that when you press in the bearing that you only apply pressure on the outer race. They gave me a good deal so I'm having them install the new bearing rather than hassle with it again.

[JCL]

Glad you found it. And it is great that you posted again and updated what it was, to help the next person.

[nas517]

Yea I had a pretty good feeling thats what it was wrong. It has to be pressed exactly on the putter edge and can not touch the black ridged part or it will damage it. It's kind of like a sensor that spins with the wheel to tell the speed/abs sensor how fast that wheels is turning. If it is pressed wrong it can damage it and not spin on the wheel bearing which will give no reading to the sensor causing a failure to the abs Dsc 4x4 and brake module. They all work together. I had the same issue with mine and I found the info on alldata. The part should be no more the $100 (around $90) and about a hour and a half labor for the wheel bearing labor ( according to alldata): glad u fixed it. Alot smoother too now huh?

[nas517]

I hate this iPhone auto spell. (outer edge)