BB, to set the scene for this, the pictures you intend to post of your mower and the cracked rails will be very important. We have had plenty of reports of SB45s cracking the front edge of the deck at the inboard engine mounting point, but I don't recall any previous report of a twin rail machine cracking both rails. It would improve our archives to see it in detail. Presumably if someone kept operating the machine after the front rail had more or less broken in half, the rear rail would then fail as well, but it would be useful to see the detail and try to work out what had happened. A key point: did this machine have the captive-cotter style of engine-side clutch half? So far the cracked rail reports I have seen may have been confined to captive-cotter machines, as have the reports of loose engine-side clutch halves causing clutch malfunction and machine vibration.
With regard to repair technique, you might take a look at this thread:
https://www.outdoorking-forum.com.au/forum/u...mp;Words=crack&Search=true#Post33516
