radius arm question

[dotcentral]

Can I use my 71 radius arms with my 79 I-beams? I have the rad arms from the 79, but not sure if they are the early or late 79 rad arms. I'll look again at the disc swap tutorial, but didn't notice it last time through the article.

[1970F250]

i think they are the same. but the 79 are stamped and the 41 are forged.
theres something on it in this

[FORDification]

Yes, they're the same dimensionally....they will bolt in just fine. However, if you go with the '73-up radius arm, keep in mind that to use the '72-older spring with the '73-up radius arm you'll have to do some minor modifications to the lower spring pad, as I did on my truck on Page 30.

However, some '73-up radius arms have the little notch in the end necessary for the factory swaybar bracket. If you ever intend to add such a setup, and your '79 radius arms have the notch, you might want to consider using those instead. Here's a comparison picture. The one on the right is on my truck now. I have the factory swaybar setup but haven't installed it yet:



I don't have a decent picture of the installed setup on a truck (mines not installed yet), but here's one on a Ford van, the swaybar bracket is the same:

[bwc302]

On the radius arm bolt that goes through the frame mount, what is considered a "safe" thickness for it to be used?

I got mine off a 76 donor 2w and the passenger side bolt looks 75% -95% in tact and the drives side more in the 35% - 60% (it has a sway back horse look going on one side).

Thanks,

Bobby

[FORDification]

Considering how plentiful those things are, why risk your life with rusty arms? Replace them both. Personally, I wouldn't use one that had ANY rust on it aside from surface rust.....nothing that had actually eaten away at the metal enough to cause pits.

[1970F250]

there are piles of them at junk yards.

[bwc302]

Then I guess what you are seeing on the parts trucks and donor's have the full thickness on the bolts?

I am/was somewhat concerned that what I have is the norm and that it might be difficult to find some that are pristine.

Thanks,

Bobby