Good evening,

I am a Noob to MB and have been a lurker on the site for some time. Thanks to all the knowledgeable folks who post useful info.

I have a 2007 GL320 with 44K miles. I had a right front wheel bearing that was groaning so I figured I would replace it before I take a long trip Monday. So my mechanical repair yields and electrical problem?

Last night I changed the right front wheel bearing. I followed this procedure. (If it wasn't so dark I would have taken pics for a write up to help others) Pulled the wheel, spread the caliper about .020/.030", removed the caliper bracket and hung the caliper with mechanics wire (did not open the brake system), removed the wheel speed sensor, removed the rotor, loosened the axle nut, pulled the tie rod and ball joints and removed the knuckle. I pressed out the drive flange, removed the snap ring, pressed out the bearing, pressed in the new bearing by pushing on the outer race, pressed in the drive flange by supporting the inner race and reassembled. Started the car, pumped up the brake before moving.

Everything went well until I started up the street for a test drive. I got about 500-1000 feet and got the infamous ABS, ESP unavailable then a shudder from the front end as I passed about 15 MPH (i assume it was the abs testing itself) then I got the ABS,ESP inoperative error.

Trouble shooting steps that I have taken.
- I checked the wheel speed sensor was seated properly.
- I removed and cleaned the sensor. There was a bit of never seize on it from the axle spline.
- I tried the ecu reset by disconnecting the battery for 5 minutes, turning the key to position 2 without starting the engine and rotating the steering wheel lock to lock in order to reset the ESP. No luck. I even tried it again with the vehicle running.
- I pulled the wheel speed sensors on both sides of the car and checked their resistance. They are identical at 550 ohms.
- I pulled fuses for the abs and esp. no luck resetting.

My next step is to find a star diagnostics system locally or head to the dealer.

Any help or direction someone could provide would be greatly appreciated.


Thanks
isirrug

 

Correct- read with star the esp module to obtain codes. My guess is that the system will indicate a wheel speed sensor error on the wheel you did the bearing on. Check plug, wiring harness at the wheel, check for dirt, etc obvious things. But yes- star/ das codes first.

 

I have made an appointment with the dealer, but due to scheduling conflicts and commitments I cannot get into the dealer until Monday the 24th. In the interim I am trying to resolve this issue any way that I can.

This morning I had the codes read by a local shop with an Autel DAS system. It indicated a speed sensor on the right side which is the wheel bearing that I changed. The codes were cleared. A short drive and the error returned.

I got a new sensor from autozone because Mercedes dealer is not convenient. It was not the exactly the correct sensor as the connector was a slightly different angle and the resistance on the new one was 1700 ohms vs 550 for the two old ones. I was able to put it in, but it was no different.

Tonight I pulled it all apart again to ensure I did not miss anything. One thing that I realized and question is that there is no slotted ABS ring (some call it a Tone ring or encoder ring.)

- So how does the sensor work? What does it detect for determining speed? It appears that the sensor is possibly pointing at and detecting on the face of the inner bearing race. Or is it pointing at the axle, but what is it detecting?

Is it possible that the bearing has one side that has a detection target and that it is directional? in other words, is the bearing possibly in backwards. I can detect nothing on the old bearing that indicated directionality.

Thanks

 

I remember vaguely something about the wheel bearing having a magnetic side and if installed wrong side out will cause the ABS malfunction..........

 

uh, i assumed the bearing is installed correctly- reluctor side closer to the speed sensor.

but yes, gen 1 bearings have the reluctor ring on one side inside the bearing. if you install the bearing in reverse it will not trigger the speed sensor (via hall effect)

the reluctor gear can be usually seen through the bearing seal surface. if in doubt get a paper clip and see which side of the bearing attracts it- that is the reluctor side.

but yes- if you didnt know that - you pressed the bearing the wrong way and the speed sensor is not seeing the reluctor gear

 

You reinforced what I was able to learn today. I confirmed today from the Mercedes Dealer that the bearing does go in one way. So the bearing is in the wrong way. I apparently put the Reluctor ring on the outside. New bearing in hand and I will replace it in the morning. I had to do a timing belt, water pump and oil change in my daughter's volvo tonight so she can go back to school.

Dad's work is never done.....

Thanks for the input guys.

 

thank you isirrug because i just did my wheel bearing and this info brought to my attention the bearing direction on install which i would have never checked

you saved me much time and aggravation

also thank others who participate to these issues

steve

 

I'm pretty sure that I installed the left front wheel bearing on my 2007 GL450 correctly as the side with the dark seal looking ring was facing the inside on the original bearing so I installed the new one with that same seal facing the center of the car. I get an amber alert on one of my instruments saying the ABS and ESP are not functioning. When I stomp on the brakes I would say the ABS is not working as at least one tire locks up. I started a new thread on this too but it now seems obvious I installed the bearing wrong side out or maybe not. Googling National Bearing 510097 it states that this bearing has an ABS encoder so I will remove the wheel and the ABS sensor and insert a small flat bladed screwdriver in the sensor hole the same depth as the sensor and see if I can detect any magnetic field by tilting it towards the bearing side surface.. I also ordered another 510097 bearing so I can check it for magnetism at the auto parts store

Do you have to support the inner race of the new bearing when pressing the hub into it? I didn't do that and maybe I should have.

 

Whichever race is the one that wedges that is the one you should work/ press and that one only. Common sense, but I have seen many diy attempts where the new bearing is destroyed because the wrong race was touched/ pressed

 

Yes you do have to support the inner race of the bearing when pressing the hub in. First time around I didn't and it damaged the new bearing just enough to loosen the encoder ring which didn't show up until I had driven a few miles, saw the ABS and ESP alerts and then started rethinking and reinspecting my work. By shining a flashlight into the speed sensor holes and comparing right to left I could tell that something was not right on the bearing I had replaced. Installing new bearing again now.

Done and all is well, i.e. no ABS or ESP alerts.

Thanks for all of the good comments which I wish I had paid better attention in the first place.

 

2007 w211 E350 - "ABS ESP inoperative see owners manual" message on the board came right after taking the vehicle on a test drive after changing the front right wheel bearing. So had exactly same story and it took me 4 times to do same job again and again until noticed that when i was putting that seal with the magnetic ring, i was pressing it too much inside the hub that caused the malfunction of the ABS speed sensor because the distance was too long and the sensor wouldn't catch the magnitude of the sealing ring. So all that fixed was the new sealing ring that pressed it inside just to the same level of the edge of the hub, not more.

 

i replaced the front lower control arms on my 2002 CL class, then i started getting wheel speed sensor code p0500 with ABS, BAS, ESP errors and stiff power steering

i took care to not damage the wheel speed sensors when i worked on the hubs

however i was not very gracious with the disc guard and bent it a little to remove the ball joints

i've tried OHM testing these speed sensors, they don't read any OHMS and i can't get them to trigger any readings by spinning the wheel and looking for DCv or ACv...

i tried a used wheel speed sensor in the front left because i thought that was where p0500 would be found...but now it seems p0500 can be for any of the 4 wheel sensors?

i tried tightening the bearing retainer on the front hub, it had some play. thought this would help but it didn't.

i've also turned wheel full left and full right, reset the battery and no luck

 

The wheel bearing must be installed with one side in or out and I don't remember which one. It can be installed either way but only if it's installed correctly will the speed sensor function, if I remember correctly.

 

 

 

 

..

 

To follow up

my issue just happened to be a rear wheel speed sensor that went bad when I was doing a handful of repairs to the front end

now, I have a similar issue after installing a new hub and front bearing on one side to resolve some steering wander. It seems the hub/bearing is pressed in too far because the amount of tightening I did on the axle nut seemed a bit extreme, however I cannot see how this would even sway properly without being pushed in that far? Doesn’t make sense to me

 

Yes the wheel bearings are directional.

 

I just had to figure this out for myself, when replacing a rear wheel bearing in my GL. The helpful part to know is that there is a tone wheel (encoder) built-in to the bearing seal/face on one side. You can tell which side this is (barely) by holding up to the light, and you should see what looks like a tone-wheel -grooves under the surface. I've found direct sunlight doesn't work, as the coating used on the outside of the seal bedazzles and sparkles too much in the sunlight. In the slight shadow of good light, and at the right angle, you can see the tone wheel. This side MUST face the wheel speed sensor. In the case of the GL, this is the inboard side of the vehicle. The other side of the bearing in my case (Timken) was mostly rubber, so there were no such reflections to be seen.
Here's a great video on wheel bearing installation with the builtin tone wheel/encoder. It gives a good explanation and shows what this encoder will look like on the bearing.