Help diagnosing an ABS fault on my Dad's old Rover 75

[FrenchMike]

Originally Posted by WayneH

Spent some more time trying to diagnose the ABS fault today. Having confirmed that the OSR is at fault, I removed the hub so that I could look at the end of the sensor and the hub itself. The photos below show the sensor, the backplate and the rear of the hub:





I gave the end of the sensor and the pick up area on the back of the hub a good clean:





I then refitted the hub and the hub nut, securing it to the correct torque and retested. Unfortunately, the problem was not fixed. The clean up did make a small difference, as I was getting one or two voltage changes from 1.60v to 0.64v per revolution of the hub but nothing like what I was getting when I tested the NSR.

So, what do you recommend I do next? Should I replace the hub or is it possible that the backplate is the issue, as it does have some corrosion? If I replace the hub, I was thinking about trying a second hand one, in case it turns out not to fix it - however, if I decide to get a new one, what makes should I avoid - or can anyone recommend how much I should spent to get a decent replacement?

Thank you

Well done,if you have noted some changes from 1.60 to 0.6 ,then your sensor
is correct .

Rests magnetic ring and gap (as small as possible )

[WayneH]

Originally Posted by FrenchMike

Well done,if you have noted some changes from 1.60 to 0.6 ,then your sensor
is correct .

Rest magnetic ring and gap

Thank you for the reply, Mike. Sorry, what did the last sentence mean? Are you suggesting the gap between the sensor and the ring could be too big? If so, what should I do next, try moving the sensor closer, replace the backplate or something else?

Thank you

[FrenchMike]

Originally Posted by WayneH

Thank you for the reply, Mike. Sorry, what did the last sentence mean? Are you suggesting the gap between the sensor and the ring could be too big? If so, what should I do next, try moving the sensor closer, replace the backplate or something else?

Thank you

Basically ,the sensor detects the small magnetic field changes (48 per turn)

remove all rust particles and try to check the gap (must be as thin as possible)

[WayneH]

Originally Posted by FrenchMike

Basically ,the sensor detects the small magnetic field changes (48 per turn)

remove all rust particles and try to check the gap (must be as thin as possible)

Thanks Mike, I was away of this as I have done a lot of reading on here before getting my socket set out.

I am just thinking, should I have cleaned up that circle of corrosion on the backplate, around the axle. Would that have made any difference?

[FrenchMike]

Originally Posted by WayneH

Thanks Mike, I was away of this as I have done a lot of reading on here before getting my socket set out.

I am just thinking, should I have cleaned up that circle of corrosion on the backplate, around the axle. Would that have made any difference?

I can't say but it's better get rid of rust (which is magnetic material).

mind you,the magnet track is fragile

Mike