| Subject: | On-Car Brake Lathe Specifications and Maintenance Requirements |
| Models: | 2006 and Prior Passenger Cars and Trucks |
The purpose of this bulletin is to provide General Motors dealerships with specifications, maintenance and service requirements for on-car brake lathes.
On-Car Brake Lathe Requirements*
| • | Capable of producing rotor surfaces with less than 0.051 mm (0.002 in) assembled runout. |
| • | Capable of producing flat surfaces (no dishing). |
| • | Capable of producing rotor surfaces with less than 0.0076 mm (0.0003 in) thickness variation. |
| • | Capable of producing surface finish of 40-Ra (Roughness Average) or less (after secondary finish operation). |
| • | All adapters, vibration dampeners, hardware and cutting inserts in good condition. |
*Essential tool CH-47661 -- Pro-Cut PFM 9.2 Auto-Compensating On-Car Brake Lathe -- meets the requirements above and supports Corporate Bulletin Number 00-05-22-002E and Corporate Bulletin Number 03-05-23-005.
Key Brake Rotor Service Procedure Requirements
| • | Use secondary non-directional surface finishing tools. |
| • | Measure and document brake rotor original and refinished thickness. |
| • | Use Essential Cleaning Tools J 42450-A and J 41013 to clean rotor hat and hub surfaces before rotor machining. |
| • | Measure all brake rotors with a dial indicator and index that rotor on the hub to correct excessive lateral runout. |
| • | Use the proper Brake-Align® Correctional Plate to correct lateral runout when necessary. |
| • | Use "Torque Sticks" torque limiting sockets or torque wrenches on all wheel nuts. |
| • | Operators properly trained and ASE-certified (U.S. only) in brake service. |
On-Car Brake Lathe Maintenance and Service Requirements
On-car lathes must be properly maintained in order to deliver accurate results. General Motors requires the following maintenance service be performed by a certified on-car lathe service technician on an annual basis.
Important: Documentation of on-car brake lathe maintenance service recommended by the lathe manufacturer must be available for review upon request.
Pro-Cut PFM 9.2
| • | Gib-way cleaned and properly torqued. Never use compressed air to clean the lathe as this can force metal shavings into areas that will cause accelerated wear. |
| • | Flange inspected, cleaned and tightened. |
| • | Solenoid inspected for timing, firing strength and position. |
| • | Tool holder plate checked for damage. |
| • | Trolley inspected to ensure that there is sufficient pivot, strength and travel. |
| • | All adapters inspected for cracks or damage. |
| • | All electrical connections checked for debris or damage. |
| • | Compensation accuracy confirmed with dial indicator. |
Hunter OCL400
| • | The I-Beam Feed Guide should be lubricated with a dry graphite spray. Never use compressed air to clean the lathe as this can force metal shavings into areas that will cause accelerated wear. |
| • | Compensation plate inspected and cleaned per the supplied operator's manual. |
| • | Trolley inspected to ensure that there is sufficient pivot, strength and travel. |
| • | All adapters inspected for cracks or damage. |
| • | All electrical connections checked for debris or damage. |
| • | Compensation accuracy confirmed with dial indicator. |
