This is great work, hopefully the results are good enough to eventually have a part available to buy from Roger.

Thanks for the hard work on this, great job.

Very promising, and thanks, Ken, for all this work- potential big benefit to our community.

Some summary tips:
1. Tip shape is important. Not a pyramid and not a fine point. Think "big screwdriver".
2. Apparently, the sensor does not mount perpendicular to the teeth in a Volvo, so it has a slight twist, say 15 degrees. You will have to machine that out, as you want the tip to be as close as possible to parallel to the teeth.
3. Tip to Tooth distance is important. If in doubt, machine it a bit too long, loosely test fit, gently spin the wheel and feel/listen for the vibration of contact. If you get some, grind of a hair more until no contact.
4. Be careful and use some type of a heat sink/ mechanical brace to keep the tip from getting too hot or breaking loose while you are grinding.

Wow! I'm just now seeing this thread. There has been a lot of great work done over the last 2 years. Ken, it looks like you've gotten real close with the rear sensor shape grinding. I agree with what you've discovered: It's very important for the flat on the sensor to be parallel to the teeth on the spindle. Also, I have an old ABS Service Book which states that the clearance between sensor and spindle needs should be .35mm. This seems like it would be difficult to hit with a grinding operation.

https://cimg9.ibsrv.net/gimg/rennlis...acb660aded.jpg

https://cimg6.ibsrv.net/gimg/rennlis...8f60ca8de4.jpg

https://cimg8.ibsrv.net/gimg/rennlis...372ba99e3d.jpg

Other note: The ABS control unit pin assignments in Post 43 are incorrect. At least for my 86.0. Pin 11 is not connected to the front right speed sensor. I had the correct pin assignment 2 years ago, but I can't find it now.

The front and rear sensors that I refurbished 2 years ago are still working, so it seems like the repair is robust. I also had a friend create a tool to reform the rolled edge on the sensor metal shell (the last step in my documentation that I didn't complete originally--linked in Post #1). I'd like to help out the 928 community by repairing some of the broken sensors out there. After doing this repair a few times, I can report that it is not too difficult if you have a steady hand with a dremel and soldering iron.

Bringing this back to the top.
I would love to hear more about refurbishing the existing sensors. Hitting a gap in a blind hole at exactly 0.35 mm (to what tolerance?) would be difficult. Any help with this would be greatly appreciated.

With the refurbishing procedure, there is no need to change the length of the sensor, so the .35mm gap is maintained by the original parts. The refurbishing steps are in post #4 here:
https://rennlist.com/forums/928-foru...d-sensors.html

Bump. Was wondering if we had any more news on rear '86 / S3 ABS sensors? Looks like from re-reading this thread we can use a dremel or similar tool on a Volvo unit or fix the existing one by unrolling the outer case and re-soldering the sensor wire where it broke. I looked around online today and it still looks like retailers are grouping the S3 rear sensors with the S4 units.

Thanks
Matt

My ABS was working fine until yesterday (84 Euro S with optional ABS). Suddenly the antilock warning came on and apparently, my rear right sensor is dead. I measured the resistance and I get nothing. The sensor wiring looks ok and measuring at the plug in the wheel well, same reading.

Is there any progress on commercializing the rear sensor replacement? Or is it a DIY job to tweak the volvo sensor? Does someone offer the repair of the existing sensors as a service, preferably in Europe, to keep shipping costs down?

We have the rear sensors being tested as we speak. Should be available in January.

That sounds like good news! Any idea on pricing yet?

Hi, I might be able to help you out, I'm in Belgium too. Just send me a PM.

You sir, are THE MAN. Thank You!!!

Hi Roger... did you end up managing to find a solution for the early rear ABS sensors?

Yes - A little bit more involved than the fronts but we have a solution.
Working on bringing it to market soon.