It's possible to convert a non-ABS car to ABS, but you will need more than the ABS module itself. You will need wheel speed sensors, wiring, more and different hard lines than what's on there now, etc.

IMO, it's not worth the effort to convert when you can just learn threshold braking, especially if the ABS system in question is going to be of questionable quality, as a homemade one probably will. Drive an early 90's ABS equipped Cadillac to get an idea of what I'm talking about by "questionable ABS".

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.