I am just in the process of repairing a fold down bollard which a delivery driver flattened for me. The plank walked past it twice and it is bright yellow but he then promptly reversed over and hooked up his van.
I have taken out the 12mm bolt on which it pivots the nut looks like a fairly normal nut but getting it off was a real PITA but it eventually unscrewed, however the threads in the nut are mangled as are the threads on the bolt where it was positioned. It was not a case of cross threading as the nut eventually unscrewed as normal off the last few threads.
Out of interest has anyone come across a nut like this and what is it called as it not something I have seen before. When I get a replacement bolt I will simply use a Nylok nut.
Richard