Rivet shank size

[Caswell]

Just started taking my car apart and I will be removing the running board brackets tomorrow or the day after, I'm going to center punch them and drill the rivet head centers, does any one know the rivet shank size, I could use different size bits until I get the right one but if somebody knows it would help, trying to not over drill bracket or frame. Pictures below of bracket type, brackets will not be reused (speedster).

[RGould1910]

1/4" shank I recall

[Aussie16]

Rather than drilling, If you have a good heavy cold Chisel, chiselling the heads off from inside the chassis rail is easy. !/4 " is correct. I but the rivets from Langs.

[Jerry VanOoteghem]

My approach would be to grind the heads flush with the running board bracket, then drive the rivet out with a punch. If they're still too tight, drill a smaller hole in the rivet, but not all the way through. Put a punch in the blind hole and drive the rivet out. The smaller blind hole allows the rivet to collapse. This way, you don't mess up the holes in either the bracket or the frame by being just a bit off with a full sized drill.

[Caswell]

Thanks all, I removed them last night, spring loaded punch, 1/8" pilot hole followed by 1/4" drill, rivet heads all fell off.

[Jerry VanOoteghem]

Thanks all, I removed them last night, spring loaded punch, 1/8" pilot hole followed by 1/4" drill, rivet heads all fell off.

That'll work too