ABS question can the experts help?

[westaussie323i]

After fitting generic ABS sensors that I hope don't work because they are generic (waiting on some Delphi from Pelican Parts) I have noticed some very strange pulsations from the brakes at low speed especially in reverse and it almost loses all pedal feel. Is this related to the sensors or a symptom of a knackered ABS unit? Or should I be taking a few shots of whisky to prepare myself for major outlay?
I was told this unit is different as it has to the setup in my E39 M5 which I had repaired and they cant fix this one??

[Timm]

That is caused by the incompatibility of the ABS sensors and the reluctance rings - at slow speed the signal is too small and the ABS unit sees this as the wheels locking - and so starts using the ABS cycle to get them moving again. However, we sometimes see this when a bit of 'effort' is required to remove the old ABS sensors and a reluctance ring gets damaged.

[georgebest]

After fitting generic ABS sensors that I hope don't work because they are generic (waiting on some Delphi from Pelican Parts) I have noticed some very strange pulsations from the brakes at low speed especially in reverse and it almost loses all pedal feel. Is this related to the sensors or a symptom of a knackered ABS unit? Or should I be taking a few shots of whisky to prepare myself for major outlay?
I was told this unit is different as it has to the setup in my E39 M5 which I had repaired and they cant fix this one??

Likely a low quaility ABS sensor (Meyle perhaps?), you need get minimum Siemens/VDO or genuine BMW.

[westaussie323i]

OK that makes sense. The rear sensors are Meyle and I assume they worked correctly as the fronts had badly corroded wires which you would think are the culprits. Being a dry country I was lucky that my sensors just popped out without extra persuasion

[westaussie323i]

Just fitted the Delphi units from Pelican Parts so I can say categorically that the generic units were the problem....took it for a test and promptly got a speeding fine!