kurtwz

Guys, just replaced my front wheel bearings. Swap went well. Got everything back together fine. When I took car for test drive, tho, the ESP was pretty much constantly activating anytime speed was over a walking pace. I felt the car slow down as the ESP activated. I turned ESP off so I could drive around a little and the triangle was blinking the whole time cus the car thought that I was doing donuts or something :-P Also the speedometer was at 0 the whole time.

Here's what I've done to fix: detached battery and waited several minutes. Also tried to turn wheel all the way to left, then all the way to right with the car running. Neither of those things fixed it. Have done three test drives now. WHAT GIVES???

****EDIT****
Few things I forgot to mention:
Right side of car: as I was trying to take the top brake pin out (thing that holds the pads in place), I didn't notice that the bracket for the brake wear sensor needed to be removed and gave the pin a few light hits with a hammer as it was touching the bracket. Might have damaged it, but they were pretty light taps, so probably not. Anyway, might be relevant to the discussion.

Left side: As I was pulling the probe out for the brake pad wear sensor the plastic piece that was SUPPOSED to be attached to the prode came off just fine. Probe did not come with it, tho. DOH! :-P Don't think that would cause malfunction for ESP, but thought I'd mention.

whipplem104

One or both of the front wheel speed sensors is not working.

kurtwz

Are you sure it's not a reset procedure that needs to be done? Is that an educated guess or have you had this problem? That would make sense, but I just need to think of all possibilities before I narrow in on one.

groove66

when you did the wheel bearing did you
1. unplug the wheel speed sensor?
2. if you did, did you happen to turn the ignition on.

If it was fine before, I would say it has to be on install. double check everything

whipplem104

I am a tech. There is no reset for the speed sensors. Either you damaged a sensor or the magnetic ring for the sensor. I cannot remember exactly what is on the front of a E55 but most of the newer cars have a magnetic ring in the grease seal if it does not have teeth on the hub. It is fragile. The rear wheel bearings have this magnetic ring in the seal on the caged double roller and it has to be installed the right direction. One way only. But if memory serves me it is in the inner grease seal on the front. I do not have that access at home to double check. A quick call to your local dealer should be able to tell you.

kurtwz

Thanks for info, guys. Pls notice additional info included above post #1 at "****EDIT****"

No, I didn't. I don't think that would be necessary, would it? It wasn't obstructing the work, so I left it. Where is it anyway? Is it attached to the black plastic cord that goes to the center of the hub? I'm pretty sure i assembled everything fine on both sides b/c i was slow and deliberate. Just took stuff off on the right side to doublecheck, tho. Things look good. No signs of assembly issues.

Oh scheisse! Just found the root cause. When I took the old seal off i noticed a black rubbery ring just on the inside of the bearing seal. I thought it was part of the seal that had become detached. Turns out on closer inspection it was a metal finely wound coil in the shape of a ring, as I'm sure you know, whipplem104 (just mentioning for others' sake). Is this the piece you're referring to? I take it that a magnet in the sensor that's mounted on the spindle behind the brake dust cover uses this metal coil to determine how quickly the wheel is turning? Is that not part of the new seal? If not, looks like I'll need two new seals and two new sensor rings :-(

Is it safe to drive the car with the ESP off? Just in terms of not damaging the car, that is? I realize that I won't have the benefit of stability control if i drive with it off.

groove66

no need to unplug.. I was talking about why esp light was on. sometimes when you have a sensor disconnected and turn ignition on it will throw a code. that is usually the reason a error message shows. that is when you would need to clear codes.

Although now you will have to clear the codes since it has sensed a malfunction

i.e. If you are doing a window regulator and don't have the airbag hooked up and have to turn the ignition on to move the regulator into position. it will throw a SRS light.

kurtwz

OK here's the update. I finally got the Mercedes grease seals and they have the speed sensor coil ring thingy as part of the seals, so I was all set to slap those puppies on last night and **hopefully** have working ESP again. Much to my chagrin i pulled everything apart and found out that the Beck/Arnley seals I used actually DO have the speed sensor coil included. So since it was ALREADY on the car and the ESP wasn't working, that can't be the root cause of the problem. That is, unless there's something weird about the design of it like it's not big enough for the magnet in the sensor to detect it or maybe it's positioned too close to the center of the hub to be properly aligned, etc.. Those possibilities are improbable, tho.

So you guys have any other ideas as to what the problem could be? I’m at a loss. My current plan is that I’m going to take the hubs apart to replace the Beck/Arnley seals with the genuine Mercedes ones on the chance that something is amiss with the B/A ones. Don’t think that’ll solve the issue, tho.