For 1990-2009 cars

# Info - On-Car Brake Lathe Specifications and Maintenance Requirements

Subject: | On-Car Brake Lathe Specifications and Maintenance Requirements

Models: | 2006 and Prior Passenger Cars and Trucks

| 2003-2006 HUMMER H2

| 2006 HUMMER H3

| 2005-2006 Saab 9-7X

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.