Why does ABS Wheel Speed Sensor contact Reluctor Ring?

[desertsage]

Hello! I'm in a bit of trouble about this and unable to find an answer on the forums.... My car is 1997 B5 Quattro sedan 2.8L SOHC 12V

I had destroyed my old seized in rear ABS wheel speed sensors while trying to remove them and bought 2 very expensive OEM sensors to replace them. When I pushed them in, they would not go in all of the way to the "fully seated" position. Still a fraction of on inch left of the shiny barrel exposed. I pushed and twisted for awhile and then after measuring discovered that the sensor is not able to go in further because its hitting the reluctor ring! When I spin the axle I can feel the pulses.

I bought the correct part number for my car but the sensor seems to be too long? has anyone come across this problem? I am very confused about this. I could pull the sensor back a little so that it isn't touching but how to know when it's the correct distance from the ring?

Advice to anyone else.... If you need to remove your wheel bearing housing, unplug the ABS sensor from under the back seat and leave the sensor installed, taking the wire with it.

Any thoughts are so welcome!

[Cybersombosis]

Yes they sit proud and do not bottom out against the upright. I didn’t install my sensor in far enough and was getting ABS pulsing on that wheel when coming to a stop at slow speeds. Took a mallet and tapped the sensor in until it bottomed out against the ring and the pulsing stopped. If you drive and you don’t get any pulsing I would leave them. You can try pulling them away if you are concerned about them rubbing but the abrasive nature of the ring will wear away a thin layer quickly and the rubbing should stop rather quickly.

Doug

[desertsage]

Ah, thank you so much! Makes me feel much better. I'll give it a go.

[Blazius]

The sensor itself should not come in contact with the ring, it works on the same strategy as your RPM sensor. Now that said the top layer can wear away slighlty but if it goes anything beyond that you could damage the sensor.

[desertsage]

The sensor itself should not come in contact with the ring, it works on the same strategy as your RPM sensor. Now that said the top layer can wear away slighlty but if it goes anything beyond that you could damage the sensor.

Thank you. I did pull it away from the ring, slightly. I tried to measure the distance with a scale, moving it away about 2 or 3 hundredths of an inch. The sensor is in there so tight that it's difficult to have much finesse with that. Just tried to make sure that it wasn't actually in contact by spinning the axle and feeling for that pulsing resistance. I hope that all will be well when I drive it. Getting the brakes back on today and all of the suspension components torqued after I simulate ride height.