Checking Grey Cast-Iron Brake Discs - Evaluating Cracks Information

Crack assessment: 

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Perforation crack length is small (less than 5 mm)

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Perforation crack length is too big (greater than 5 mm)

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Friction plate rim damaged

• Perforation crack length is small (less than 5 mm): No replacement necessary (the maximum permitted perforation crack length is 5 mm)  > Perforation crack length is small (less than 5 mm) 
• Some perforation cracks are over 7 mm long: Brake disc must be replaced.  > Perforation crack length is too big (greater than 5 mm) 
• Brake disc with cracked friction plate rim: Brake disc must be replaced!  > Friction plate rim damaged 

1. Perform visual inspection and measure crack length using a suitable tool if necessary.