Table 1: | Ammco Brake Lathe Refinish |
Table 2: | Accu-Turn Brake Lathe (One Cut Refinish) |
You do not need to refinish the brake rotors when doing a routine brake maintenance such as replacing worn brake shoe and lining assemblies. Refinish the rotors only in the cases of brake pulsation, hot spots, or excessive scoring.
The brake rotors have a minimum thickness dimension cast into them. This dimension is the minimum wear dimension, it is not a refinish dimension. Do not use a brake rotor that will not meet the dimensions shown in the specifications chart after refinishing. Replace any rotors which are too thin as they will not have the proper heat transfer capabilities. Refinishing the composite rotors requires the use of a six lug or eight lug composite rotor adapter.
An accurate control of the rotor tolerances is necessary for the proper performance of the disc brakes. Use precision equipment for all of the machining. Service the machining equipment on a regular basis following the manufacturer's recommended maintenance procedures.
When refinishing the rotors, make sure the attaching adapters, tool holders, vibration dampeners, and tool bits are in good condition. Make sure that all cutting tools or bits are sharp and use only the replacement cutting bits recommended by the equipment manufacturer. any dull or worn tools will leave a poor surface finish that will affect the initial brake performance. Always use vibration dampening attachments when refinishing the braking surfaces. The vibration dampening attachments will eliminate tool chatter to allow for a better surface finish. Keep the vibration dampening attachments clean and free of nicks.
Following are two recommended procedures that achieve adequate results using two different off-vehicle drum/disc brake lathes, the Ammco Brake Lathe and the Accu Turn Lathe (GM dealer equipment) off-vehicle brake drum and brake rotor lathes. Follow the manufacturer's instructions and recommendations when using any other brake lathe.
The finished brake rotor surface should be as close to that of a new brake rotor as possible. Failure to obtain the best possible brake rotor finish can affect initial braking performance.
| Rough Cut | Finish Cut |
---|---|---|
Spindle Speed | 150 RPM | 150 RPM |
Depth of Cut (Per Side) | 0.127 mm (0.005 in) | 0.051 mm (0.002 in) |
Total Cross Feed (Per Revolution) | 0.152-0.254 mm (0.006-0.010 in) | 0.051 mm (0.002 in) Max. |
Vibration Damper | Yes | Yes |
Swirl Patter-120 Grit | No | Yes |
Spindle Speed | 150 RPM |
---|---|
Tool Cross Feed (Per Revolution) | 0.076 mm (0.003 in) |
Tool Bit Nose Radius | 1/64 |
Vibration Damper | Yes |
Swirl Patter-120 Grit | Yes |