Drilling out Lower Control Arm U-bolt holes for 9/16" U-Bolts

[RoyL]

Passing on in case others are going to upgrade your smaller 63-66 U-bolts to 9/16" when swapping to '73-87 C10 control arms for disc brakes or whatever reason.

Get a sharp bit...
Drill from the bottom and put a tight fitting bolt in the opposite hole to keep the saddle bracket from moving.

One of mine shifted a tad when the drill bit caught the bracket as it was almost thru. Before I realized it, I drilled out more of the bracket than needed, which caused the control arm not to want to seat in the alignment pin. So I had to line up the saddle and ream it out some more so the pin would line up.

I ended up using a 5/8" bit to get the 9/16 u-bolts through.