Put nut washer and shim on a long plastic zip tie, push through the hole and pull up tight. Reach underneath and hold everything in position, let zip tie fall out, insert bolt and start form the top.

you're welcome. I realize this thread is older but this is a difficult thing to do.
__________________
Bill Woods
RV 8 QB
IO360A1B
Hartzell CS BA
RV8 sold

180 hrs. of pure joy

(Nov 2018) Bought 7A Tip up
project, converting to tailwheel
slider (just because)