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Tracking down the cause of pad wear warning, the sensor on one side is missing but the other side was just tie wrapped off the pad and it doesn't fit. The body of the sensor is too fat to fit in the pad slot, it's a double sensor and neither fit as per picture below. PET shows part number 928 612 315 02 with the correct connector but is it likely to fit? The pads were very hard to slide out of the caliper so I'm wondering if they’re the wrong pads. It's an '86 S2 Euro with 4 pot at the front.
Hi Gary it's a little hard to tell from your photo, but you are probably trying to push the wrong part of the sensor into the slot! Because it's head-on photo I can't see, but there is a smaller section behind the sensor head, with spring clip around it (can you see clip?). The clip slides in smaller slot that is kind of stepped behind the large slot in pad for sensor head.
If the pads were hard to slide out, the simpler and more likely explanation is that your four pot callipers are suffering from side plate corrosion, where the stainless steel pad support plates on each side are being pushed out by corrosion between them and the aluminium body of caliper. If you look at the sides caliber where pads fit you will see these plates, and whether they sit perfectly flush or not to caliper. If the callipers have never been referred, it is almost certain you have problem with these side plates. Some people get round this by grinding edges of pad backing, but this is a bit of a bodge and much better to attend properly to the side plates.
Thanks for the response, there's no clip on the sensor it's just a T shape. The picture below might be a bit clearer. Can't see how it would slide in any other way, the base of the T has to face the disk as far as I can tell.
The plates either side of the pads were pushed out a bit so your right about the corrosion, I'll add it to my list !
Missing the little metal spring clip that secures it in the slot. Used pads end up with lots of brake dust packing the slot. New pads have the slots packed with paint. Either way the slots need to be cleaned completely before the sensors will come out or go in intact.
02-25-2017, 11:20 AM
Pad wear sensor
