Gap size between rear ABS sensors and sensor rotor teeth (1 Viewer)

[interactivebagel]

Just did my rear wheel hubs: bearings, seals, races, etc. and I noticed that the DS hub went on much easier than the PS hub. On the passenger side I really had to force the hub to the back of the spindle and tighten the bearing lock nut. The oil seals at the inner bearings were identical. Anyway, the gap between the ABS sensor and the sensor rotor teeth on the PS is 1/8". I felt like the the DS was more snug, although I didn't measure that gap before I buttoned it up.

Now, braking at stop signs I'm feeling a vibration in the pedal like the ABS is coming on and low whining noise that sounds like it's coming from somewhere near where the brake pedal attaches. Could the 1/8" gap be the culprit? Is 1/8" too large of a gap? There is no mention of spacing in the FSM.

 

[beachboyy]

I have my rear apart right now and mine is way closer fit than that. I am not saying that is what is causing your vibration but you definitely have a bigger gap than I do.

 

[MoCoNative]

Revival time, I'm having a similar problem. Re-did the rear end of the 80, new bearings, races, seals. Even replaced all the suspension bushings front and rear, did the front axle as well the week before. I only broke the 12ton harbor freight press twice while doing the bushings.

The front end all went good, brakes have been better than ever, turned the rotors, new pads, new bearings, new spindles, and a new master, finally the 80 will stop and the pedal does not fall to the floor like it was.

Wanted to do new bearings on the rear, calipers and pads were newer back there already. I knew the bearings were worn, thought freeplay in them was affecting the brakes, but they were still good and tight. Either way it is all refreshed now. Got it all buttoned Sunday evening, take off and I'm getting the ABS actuation when rolling to a stop and the speedometer drops to and below 10 MPH. ABS light flashed one time Sunday, I think, light never came on or stayed on while driving. Decided it had to be a rear sensor issue as it showed up after the rear end work and was not pulling to either side as others had noted if a front sensor was out. Pulled the ABS codes last night and I get a code 33, which is "Right rear wheel speed sensor signal malfunction."

Oddly, I stretched the left side loom kind of roughly to get the lateral control rod out, figured that was the side that would be screwed up. I did spray down the e-brakes and backing plates with a small battery powered pressure washer, so it was nothing traumatic, but I did introduce water to the area. My first guess was maybe a wheel sensor was damp and would dry out, but it has not. Pulled both sensors out the backing plate late Sunday evening, nothing was stuck to them, I cleaned them well prior in the day wiped them off again.

I did wonder about the gap/depth that the hub slid on, seemed to not go on far enough, but I wiggled it and stabbed it a couple times and it seemed to seat properly. I'm sure my inner race was seated. I thought about it some, but decided that the caliper went on flawlessly, so if the hub was not seated properly I would have a problem with brake rotor alignment, but I did not. I know I had one little stringer of wheel grease on that sensor rotor, between two teeth, that I don't think I wiped off, I can't imagine that would throw it off considering the fine crap that accumulates on the sensors from the brake dust.

I'm going to check the wiring and sensor, but I am curious what the gap should be. I'll also pull the wheel/rotor and see if that little dab of grease is the issue. I see on RockAuto there are sensors available with different lengths, they only differ by 0.5mm, so that is not much of an adjustment, when the gap seems pretty large anyways. Just curious what it should be, I can't find a spec anywhere either.

 

[MoCoNative]

Well to recap, the space from the sensor to the rotor should only be about a millimeter. I checked all the wiring, and sensors. Pulled the right wheel and rotor off, had the large gap like original poster shows. Sensor and wires checked out, but it would not generate an AC current when spinning the wheel. Broke down and took the left wheel apart, sure enough, very thin gap and it would make AC current easily on the sensor.

So, I pulled the axle and pulled the hub off, guess what stayed behind on the spindle in the new grease. The spring from the wheel seal. About 1/8+" thick, had the hub spaced out too far. Amazingly the wheel bearings torqued down properly on top of it and felt fine. Fixed the seal with a spring from one of the old seals still laying on the bench, as the new one was kind of mangled, and it all went back together as it should and the the sensor made AC current readily and the ABS actutation at low speeds is gone. I've never had the spring come out like that, not sure why it did, maybe I dislodged it putting in the seal, or too much grease caused a burp that pushed it out, either way I got it fixed. Glad I didn't have to fork over the ridiculous money for some wire and a simple magnetic sensor. That is just plain robbery what the ABS wheel sensors cost to replace.

 

[interactivebagel]

So, I pulled the axle and pulled the hub off, guess what stayed behind on the spindle in the new grease. The spring from the wheel seal.

Pretty sure this happened to me too. Eventually I got it on snug with the ABS sensor about 1mm from the teeth. Glad you worked it out!