Lesson #6: Final Steps

At this point you have completed two critical tasks

• Matched the rotor to the hub by taking into account the imperfect nature of the hub and the stacked tolerances from the hub and other components, thereby eliminating a potential pulsation comeback.
• Given the braking surface a new, clean, flat finish that is nearly ready to be mated to the friction material.

The finished surface, by virtue of the off-center design of the Pro-cut adapter threaded center hole, does not require non-directional finish sanding. The design allows the cutting tips to travel in an orbital motion. This eliminates the tendency that bench lathes have to cut a record groove, or a continuous pattern into the rotor that can cause brake noise. However, if you prefer to do a light sanding to reduce the surface finish Ra even further, we suggest 150 grit sandpaper and a half arc sanding block such as the 3M pn# 9292.

Lastly, wash and dry your rotors! Use a spray bottle with warm water with a few drops of dish soap and white paper towel!

• Do not use shop rags due to safety concerns of entanglement!
• Do not use Brake Clean as it does not work as well for removal of cast iron dust.

The smoother and cleaner the surface, the less potential for a "growl" or other unwanted brake noises!

Final Notes:

• If for any reason you must remove the rotor after completing the match-machining process with the PFM lathe, be sure to match-mark the rotor to the hub with a crayon so you can replace the rotor in that same position. Failure to do this will result in a complete undoing of the LRO correction you just finished! For this reason it's always preferable to use the PFM last after all other suspension/hub/axle work is compete, and the wheels are ready to go back on the vehicle.
• The lug nuts for the wheels must be torqued to manufacturers' specifications and in a star pattern order. DO NOT use an impact gun without the proper TorqStik or a torque wrench. Uneven torque of lug nuts/bolts will cause the rotor to deflect and will actually induce LRO and cause the undoing of the nearly perfect brake job you just performed!
• Test drive the vehicle and follow brake pad manufacturer's recommendations for bed in of new friction material.