I think there are more first gen cars with ABS than 1985, but they are hard to find. I know I have seen some earlier models with it. I dont know about the interchangeability of them as my SD does not have it. I remember there being only three sensors. Cleaning seems like a good idea. I remember a plastic bag got caught up in my rear end and cut the sensor wiring on the diff of the 420 once. I used butt splices to crimp it back together and it worked. They are pretty reliable even though they are exposed to everything.

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1984 300SD Orient Red/ Palomino
1989 560SEC
2016 Mazda 6 6 speed manual
1995 Ford F-150 reg cab 4.9 5speed manual