[mattmartindrift]

the exact steps:

- fabricate brackets that adapt the E60 caliper to the E39 knuckle.

- bore rotor center to 74.1mm

- install rotors/calipers

- bleed brakes


Basically, if you're asking, it's going to cost you more to have all the parts custom fabricated than it would to just buy an off-the-shelf BBK.

 

[mattmartindrift]

any machine shop that can bore the center of the rotors, should be able to make your adapter brackets. You'll just need exact measurements of the rotor offset and it's relation to the OEM mating surface for the caliper, then you'll need to do the arithmetic to calculate where to drill the E60 caliper bolt holes in relation to the OEM E39 bolt holes (on the adapter bracket).