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      10-23-2017, 07:06 AM   #12
rasa bmw
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Drives: space grey 640d sport e90 330d
Join Date: Jul 2017
Location: northumberland

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Originally Posted by AndyVR View Post
Fitted a new rear sensor at the weekend.

Turns out my car has the old style reluctor rings on the driveshaft! 2010 must of been the changeover year at some point? mine was built June 2010.

Problem was obvious - reluctor ring was distorted, two high spots on the ring that have been polished by the sensor. No visible corrosion, rings were in good nick otherwise. The end of the sensor was worn.

I measured the distortion in the ring, it was about 0.75mm at worst point. The sensor was worn by about 0.5mm, so when the car was new the sensors must run very very close to the ring to start with.

Older cars I've known have had a much bigger sensor gap.

Not wanting to start removing driveshafts/new reluctor rings, I fitted the new sensor with 1.5mm hard rubber washer around the sensor body, and another one under the fixing bolt. (originally tried a metal washer just under the bolt, but figured water would get down the sensor hole and cause issues.) the sensor is now clear of the ring but hopefully close enough to give proper readings - so far the car is driving perfectly now, no warning lights.
yeh keep us updated,i get the odd flashing light,usually hwen been parked up after turning off,then starting and pulling away.usually round a rihght hand bend,very rare though,,
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