redneck. you are correct. i was just stating that the 250s did use a TTB setup but they wont have the part he is looking for. you are correct that they use a leaf setup and no radius arm/coil...
on the other note i 100% agree with bill. the thing that makes a grade 8 bolt a grade 8 is the alloy(specifically the carbon content). Its a medium carbon alloy which gives it the ability to stretch a bit before it fails under loading. In addition it is also tempered. Ive had mechanics of deformable bodies classes and materials classes and i wont bore you will all the details but there is a lot of rearranging of the carbon inside the substructure of the metal during a temper. tempering takes place between 500-700 degrees and its kept at the temp for x-time and cooled slowly.
the important thing to note is the phase change for steel is above 725F. if you got that bolt cherry red when welding you can be sure it was over 1000degrees and not only is the temper gone but you've now made the bolt very weak because during cooling in air you allow oxygen to occupy interstitial spaces in the substructure. This is why tig welders use gas shielding and it flows for a period of time after you weld to cool the weld in an oxygen free environment. and stick welders or flux core mig welders use a flux to shield the weld. if youve use a stick welder you know you have to chip off the **** after you weld with it.
Good luck with it and i really hope it doesn't fail but if I were you I would be looking for a replacement arm to keep on hand.
If I had to fix a radius arm like this i would weld a 1/4" thick steel plate to the end of the radius arm and run a non-modified grade 8 bolt through this plate. This would only be temporary though.
