I think I can count myself extremely lucky where my 635 is concerned.  After over 2 yrs of storage I managed to go through an MOT with her with just 4 patches of welding required underneath, a tell-tale direction indicator and ABS indicator light on dash not working. 

The dashlights are jerry-rigged now so the ABS comes on only with the ignition light as the ABS system itself is in perfect working order, the light on the dashboard actually had no bulb holder or wiring to it.

The tester even commented that the brakes were exactly on book values when it came to the brake test, which was not only surprising when considering the car is 23 yrs old but one that has been stored too.

I can definately call myself very lucky with my car, I bought it for very little money, its one of just 4 on the Island, it has the second highest mileage but is in the best overall condition and is the oldest of the 4.

Being medically retired means I have plenty of free time on my hands so eventually she will look her best again.  Fortunately the previous owner threw huge chunks of money at the car, so all her main mechanical systems are in A1 condition.

Jonners,

     it sounds to me like a front wheel problem; either the ABS wiring might be at fault, a sensor or a wheel bearing is shot. Any could cause an erratic reading from one ABS sensor; the car will then pull to the other side on the brakes, which will  be 'pulsing' if the ABS activates.

If the ABS fuse is pulled, the system should deactivate. Under normal circumstances the car should be safe to drive like this, but have him test it off the public highway to be safe. If the fault goes away then it is almost certainly an ABS sensor problem as described above.

I hope this helps;

cheers