LW2 V6-3.0L VIN R (2000)
Brake Rotor/Disc: Service and Repair
Refinishing Rotors
Accurate control of the rotor tolerances is necessary for proper performance of the disc brakes. Machining of the rotor should be done only with
precision equipment.
All brake rotors have a minimum thickness dimension cast into them. This dimension is the minimum wear dimension and not a refinish dimension.
Do not use a brake rotor that does not meet specifications.
If rotors are removed, remove rust and scale from the rotor/hub and rotor/wheel mating surfaces. Failure to do so can cause excessive lateral runout
when the rotor is mounted on the brake lathe or when the rotor is installed to the hub.
IMPORTANT: When refinishing rotors, always use sharp cutting inserts (bits, tips). Dull or worn inserts leave a poor surface finish which will affect
braking performance.
Make sure brake lathe is clean and free of debris before turning rotors. Remove metal filings from the mating surface between the lathe and the cutting
assembly. Remove filings from behind the tool bit holders.
Some brake lathes (Accu-turn or equivalent) can refinish a rotor's surface with one cut, regardless of the depth. HOWEVER, ROTOR MUST NOT
VIBRATE DURING REFINISHING OPERATION. Use the vibration dampening devices provided with the lathe.
Manufacturers of brake lathes that cannot control rotor vibration during deep cuts recommend several cuts to achieve desired finish. Following the
instructions provided with the lathe will help ensure high-quality machining. Again, always use the vibration dampening devices provided of lathe.
Regardless of brake lathe used, a shallow finish cut will not yield best surface finish. A shallow cut of 0.051 mm (0.002 inch) "smears" the rotor's
surface, creating a rougher-than-desired finish. Cutting at least 0.127 mm (0.005 inch) (per side) will leave a smoother surface, resulting in better
brake performance.
IMPORTANT: Make sure to use the proper cutting inserts. Use the cutting inserts recommended by the brake lathe's manufacturer.
Check the cutting inserts' condition regularly. Replace them at the first sign of inferior refinishing. FOLLOWING ALL THE LATHE'S MACHINING
INSTRUCTIONS WILL FACILITATE ACQUIRING THE DESIRED SURFACE FINISH.
All brake lathes use a single-point cutting tool. THIS TOOL WILL NOT YIELD THE NECESSARY SURFACE FINISH. A SECONDARY
FINISHING OPERATION MUST BE PERFORMED. To obtain the necessary finish, follow this procedure: With the rotor turning on brake lathe,
sand each side of rotor for a minimum of 90 seconds with 150 grade sandpaper mounted on a sanding block. Use moderate pressure. After sanding,
clean rotor THOROUGHLY. Use Saturn Brake Cleaner P/N 21007432 (or equivalent).
THE SURFACE FINISH QUALITY OF A MACHINED ROTOR SHOULD BE AS HIGH AS A NEW ROTOR. FAILURE TO OBTAIN THIS
BEST POSSIBLE ROTOR SURFACE FINISH WILL NEGATIVELY AFFECT BRAKING PERFORMANCE.
ROTORS OR DRUMS SHOULD ALWAYS BE REPLACED IF MACHINING RESULTS IN A ROTOR OR DRUM THAT DOES NOT MEET
THE SPECIFICATIONS FOR MINIMUM ROTOR THICKNESS OR MAXIMUM DRUM DIAMETER.
