Can you post a pice of your parts? on the 280 the order is

Rear: First install bearing (correct angle orientation- smaller diameter side of inner race first) push on inner race of the bearing not the outer or you'll break it open...then rear spacer(small diameter), then turbine wheel (blade's leading edge towards the center of the axle, yes this sound obvious, but sometimes it seems it isn't...)
Insert assembly into turbine from the rear making sure that it seats all the way in.

Front: Insert washers (you need as many as there were before...) then install front bearing, again smaller diameter inner race first make sure bearing sits propery, push on the inner race of the bearing not the outer or you'll break it open...then insert compressor spacer, then compressor, then nut...