i am about to take the 3104 in for painting. i need to replace the bolts on my running boards. they use a somewhat special bolt available, kinda like a carraige bolt w/ a flat head ??? from vendors.
ok
i am using ''elevator bolts'' or another common name is table/ cabinet leveling bolt. it has a big flat head w/ a square shank just below the head. these are designed and used to level tables or cabinets. the square shank is to allow you to turn the bolt up/ down. they come in 1/4''x 20, perfect for our bolts running board. the flat head & square shank is like a carraige bolt but these are (i believe better). to make them fit you will have to belt sand/ grind down two straight sides off the big round head. then you can slid them in to place in the running board slots.
they fit perfectly and a set of 12 cost my $1.00.

hope this helps

Jim & Caroline
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