@sierrafery - Fantastic write up + 1 sir.
@Jalfrezi - The D1 ABS has great big muckle teeth in the ABS rings bolted to the back of the discs, they could almost pass for diff pinion gears. I suggest you remove the sensors and peer into the hole, if you can't get your mk1. organic forward looking optican sensor (eye) in about there, go on amazon or eBay and get a cheap plug into your phone borescope for less than a tenner.
The reason I say this is your starting point is that D1/RRC ABS discs need to have the extra 5 holes drilled into them for the ABS rings, I myself fell fowl of this and bought "non-abs" discs for my RRC a few years ago, and didn't discover the error of my ways until I had the halfshafts out and oil on the workshop floor, I suspect I won't be the only one to make this mistake. I did however, nip up the halfshafts, and order new discs, as I didn't need the vehicle on it's toes straight away. I suspect many people who daily a disco, were they to make that mistake might just wing the ABS rings and fit the new discs, and that could be the start of your problem. But if the ABS rings are there on the inside of the discs, it's most likely a wheel sensor, but they are a bit pricier than a borescope for your phone which is why I'm saying to start there.
@Jalfrezi - The D1 ABS has great big muckle teeth in the ABS rings bolted to the back of the discs, they could almost pass for diff pinion gears. I suggest you remove the sensors and peer into the hole, if you can't get your mk1. organic forward looking optican sensor (eye) in about there, go on amazon or eBay and get a cheap plug into your phone borescope for less than a tenner.
The reason I say this is your starting point is that D1/RRC ABS discs need to have the extra 5 holes drilled into them for the ABS rings, I myself fell fowl of this and bought "non-abs" discs for my RRC a few years ago, and didn't discover the error of my ways until I had the halfshafts out and oil on the workshop floor, I suspect I won't be the only one to make this mistake. I did however, nip up the halfshafts, and order new discs, as I didn't need the vehicle on it's toes straight away. I suspect many people who daily a disco, were they to make that mistake might just wing the ABS rings and fit the new discs, and that could be the start of your problem. But if the ABS rings are there on the inside of the discs, it's most likely a wheel sensor, but they are a bit pricier than a borescope for your phone which is why I'm saying to start there.
