You would have probably required a 3/4" or 1" socket set, and a 6ft bar on the end. They are probably only done up to 220lb/ft! And someone on the brakes to stop the shafts rotating. And even then it still wouldn't have got just your discs off!
I haven't looked at the brakes on the 145, but guessing they follow 'normal'/similar setups..
remove the calipers, then the discs should be held on by 2 (maybe 4) bolts. Then they should just fall off in your hands.
BTW - may be horribly wrong as I haven't looked at mine yet, someone better correct me, quickly, before bazza trys to take his driveshafts out.. wink
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