The deck has started to degrade and the wheels are supported by the sides where it's the weakest.
Step 1: Things you'll need.
Materials you'll need:
4 Brackets 2" x 2" x 1/4" angle x 3 1/2
(I got these at my local fabrication place and the cut them and cleaned them up for me)
8 bolts 1/4-20 x 3/4" (I replaced what old hardware I could)
8 nuts 1/4-20
8 washers 1/4 size i/d
Tools you'll need:
Spanners (open/closed end wrenches)
Ratcheting wrench & sockets