Bill- Yes, lot's of front brake center bolts have been bent. The typical cause is from a fall over that allows the ft. wheel to swing around far enough so the brake caliper arm (that the cable adjuster threads through) strikes the down tube and bends. Often a mark on the frame is left (including small dents) and the brake arm can also bend or twist. Your description sounds like something else impacted the brake. Perhaps the bike was assembled with a bent center bolt. The classic boxed bike (Back in the Day) would have had the Ft caliper in a parts box with pedals and such.
Either way, you're trying to repair the lesser bent bolt is a good one. The key is trying to isolate the correcting bend to the same spot as the damaging one. Most all the bolts that I've seen have the bend right up against the back/frame side of the big diameter spring holder/frame face. You could clamp the long portion of the bolt in your vice (with thread protection) and whack the large diameter piece with a wooden drift punch (dowel)(to not mar the chrome). A hammer and anvil might not offer the control to avoid scars and get the bolt looking straight. Function does not require a super straight bolt and you won't see it, in the crown and all. But one does try to do good looking work when possible.
Settling into winter, I am cleaning and rebuilding components on recent eBay rescues, while watching bad TV shows. I disassembled a Nuovo Record front brake from a 1973 original equipment Bottecchia. When I got down to the center bolt (Part No. 2012) I found the thing to be bent. The long end of the bolt, that goes through the crown, is pretty badly bent, with the worst part of the bend at the front end. If you look at the bolt from the front of the bike, the bolt is bent up and to the right side of the bike, kind of toward the 10 o'clock position. I ask myself: How does this happen? I am confident this is original equipment on this low mileage bike, which shows no damage to the bike or to the brake assembly, other than this bend to the bolt.
This is the second one like this I have encountered. The other is in my parts bucket since a couple years ago. Same problem, but not so severe a bend. I will probably use a hammer and anvil on this bolt to see if I can salvage it.
I can't imagine what kind of stresses on the brake could cause this bend. Anyone else ever see this problem?
Bill Kloos Eugene, OR 97401 Phone: (541) 343-8596 e-mail: firstname.lastname@example.org **************
Andrew R Stewart