Radius Arm to frame nut size?

[Docmace]

Does anyone know what size socket I need to remove the nut on the rear of the radius arm?

Also, when I went to pull the cotter pin it was rusted and separated making it unable to be pulled completely out. If I get the bolt loosened, it should just shear the pin fragments still extending in the bolt as I turn the nut, correct?

 

[gr8scott]

1 1/8" socket, and yeah it should shear off those cotter pin fragments.

 

[Apogee]

If you're lucky, the nut comes off with some additional effort, but it would be a lot easier if you just punched the cotter pin remnants out with a drift first. If you're unlucky, with or without the cotter pin, the nut galls on the radius arm stud and you get to take it off with a torch.