the tubing is 3/4in and get two 3 foot ones or 1 4 foot 1
for the back axle u get a 4.5 in long bolt and its 5/16ths
the back axle will go all the way through so put back wheel spacers in the boxes so the bolt goes through them and it wont bend
for the front bolts use 1/4 in bolts and bolt it all the way through remember to use the holes already in the deck
for the brake u can do the same as the front but u have to drill your deck and brake to 1/4
but if you want to do it normaly just cut a hole where the bolt is like a querter inch on the top and side
hope i helpedddd =]