Crankshaft bolt - 12.8 solidity - for beltdrive wheel. Must be repalced if engine has old type of bolt 8.8 solidity.
Please check - if 8.8 (6 side bolt) is to find at your engine it must be changed to 12.8 (12 side bolt).
Loosening the Crankwheel (because of old type of bolt) is very dangerous for the engine.