- Track down new bearing cap bolts
First stop was to check out Ottawa Fastener Supply. With the assistance of the guys there, we concluded that these are not common bolts but specific parts for the OM660.
They are RIBE (Richard Bergner) Aluform Bolts, M9, 100mm (currently 104, most likely due to the TTY application), with some sort of dry lubricant on them.
Next stop is eBay and other European stores to try and track down new ones. Worst case I'll have to go against my own words and use them again if I can't find a suitable replacement.