I has some positive, but not conclusive results. The sensor I got that looks the sames as Roger had for a Volvo:
https://cimg9.ibsrv.net/gimg/rennlis...ccc496ddf7.jpg

Looks to be very, very close dimensional to the FRONT ABS sensor:

https://cimg0.ibsrv.net/gimg/rennlis...aa966b0c98.jpg
https://cimg2.ibsrv.net/gimg/rennlis...1545fd1b8e.jpg
https://cimg4.ibsrv.net/gimg/rennlis...a8cfcc40e5.jpg
https://cimg5.ibsrv.net/gimg/rennlis...0d3f4cff8a.jpg


I did not get a change to do any actual installation, as I had to get everything buttoned up for track event next weekend and did not want to start anything I could not finish, or that would be an unknown variable on the track.

So, no actual testing until next week, but will post results as I gather them.

Related note: since the original connectors are crumbling, I have been using connectors like these as replacements. Good enough, or is there a better alternative?:
https://cimg8.ibsrv.net/gimg/rennlis...065fe2d607.jpg

I have good news. The Volvo style sensor :Manufacturer Part NumberABS193 3515092
ALS554Found here on Amazon:
Work as front sensors, with the following caveats (none of which are a shock):
1. You need to replace the connectors
2. The grommets don't match up perfectly
3. They do not have the "barrell grommets" that clip into the OE wire holder clips. Barrell Grommits is my term, don't know what they are really called. If somebody can tell me the right term, I can search for a source.

But the head fits perfectly in the spindle, and it delivers the required signal pulse. Testing show no errors, and thanks to heavy rains today, I was able to confirm that ABS worked as expected when the brake pedal is mashed .
https://cimg6.ibsrv.net/gimg/rennlis...40f9fdcdfb.jpg
https://cimg2.ibsrv.net/gimg/rennlis...39e1662206.jpg
https://cimg3.ibsrv.net/gimg/rennlis...73825c9ab0.jpg

If this was going to be offered as kit, I would expect:
1. The connector already installed on the sensor and, plus one to replace the harness end. Challenge is that crimping these is done best with the correct style crimper, something many will not have. Alternative to pre-assembly is to include a correct style crimper in kit ( or as option) and detailed instructions.
2. A nice grommet for the pass through of this wiring, the brake fluid line and the brake pad sensors. Mine is a bit of a hack job, and I DEFINITELY did not want to disconnect the brake line for this. I basically have three grommets that sort of fit, held in place with black silicone. Functional, but ugly.
3. "Barrell Grommets" on the wire that allow use of existing OE wire clips. I used wire ties, which are functional, but ugly.

The bad news: This still did not solve my issue, in that firm bump puts the system into fail mode. I have replaced:
1. All four sensors
2. All relays
3. ABS ECU
Only things not swapped so far:
1. ABS Pump
2. ABS Harness
:mad:

Back to more good news:
I may have a sensor that DOES fit rear perfectly ( except for electrical connector, as expected). Since I don't think I am having issues with my rears, this is a lower priority for me.

Great progress, Ken- thanks for taking on this project!

Hey Ken, question about the front connectors...how are you getting to those? I have early '86 and those things are way down there! Just curious did you go through the wheel/fender, or down from the top in some way?

Thanks!

This is awesome Ken thanks so much...so basically I fish the wire upwards so we can make the connector change ..you're basically behind the shock tower but in front of the brake master cylinder...a tough fit but if you can make it so can others. I'll be so glad not to have to hit the trouble light dismissal button every time I start out!.

Amazon Link for what I am going to try:

Doesn't take a sharp eye to note the above does not look like the OE. Comparison:
https://cimg2.ibsrv.net/gimg/rennlis...738935c37c.jpg
https://cimg3.ibsrv.net/gimg/rennlis...4f58ebb4a9.jpg

But, it looks to have all the same critical physical dimensions: Length, Diameter and mounting hole placement.
Electrically, it shows about 1,000 Ohms resistance, which is in the range we want.
So, assuming it does fit, all it needs to do is generate a pulse that the ABS ECU recognizes, which I am 75% certain it will do.

BONUS: Comes with two sensors, cheap. I would recommend you replace both

I will probably test out this weekend, but if you get a jump on it, please post results.