Looking through my K100RS 16v history there is mention of an ABS problem and the BMW service invoice says that they "suspect the rear modulator" as causing an ABS problem. Wondering what a modulator was I googled it and came up with pictures of what I thought was the ABS pump. Is this one and the same thing?

Looking at the manual, bleeding seems to be achieved using an adaptor that fits the cylinder and allows use of a pump to force fluid through the system. Is this the only way to be certain of cleaning old fluid out of the system.

Proudly wearing my "K" apprentice T shirt.

Dunney

The function of the modulator is to let off and then re-apply braking
pressure to keep the wheel from remaining locked up. It's controlled by the ABS "brain".

So yes, ABS pump and modulator would be the same thing.

...and I found this too. With thanks to the Motobrick Forum.

Yep it's the same thing. I use a vacuum bleeder to do my brakes.
You can buy a hand operated ones on Fleabay and pressure ones but they are a bit more like heaps more or just pump by hand which sometimes works.

If you opt to use a vacuum bleeder then apply a bead of silicone grease around the junction between the bleed nipple and the calliper or bleed nipple of the modulator body (whichever you are working on) or you will suck in air down the thread giving a steady stream of small bubbles which never stop BTDT. The grease blocks the air from going down the threads.

You may come across descriptions of arcane machines being used by dealerships as required to bleed ABS brakes but that applies to the servo assisted brakes used on some models (not our bikes).

For all practical purposes there is no difference in bleeding the ABS and non ABS K except you have a bleed nipple on each modulator to do as well. The suggestion about activating the ABS mentioned on the link is a good one as it gives the system a run, gives one experience and can't hurt.
Regards,
K-BIKE

Very helpful as ever.

Thanks

Dunney

for a view into the modulator ABS1

detailed pics:

pls look here