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Hey all, I recently pulled my front end apart to change out the radius arm bushings only to snap off the bolt. I have a 2wd f250 light duty w/7/8" king pins front end. The other side is not much better from years of salty roads. I wasn't too concerned at first, now I'm having some trouble locating a new ones.
I have a big truck spring shop local to me, is this something fixable, by cutting out the old stud and welding in a new one? Going to my local junk yards would be a waste of time as most will be like what I have now.. any thoughts or input from the collective minds of the forum?
You could probably get on Car-Part.com and get a pair of radius arms from a wrecking yard in a more salt-free state.
It's hard to say for sure from just a picture but, those radius arms don't look any different from the '77 F100 radius arms that I have on my '69 F100.
The radius arms are interchangeable from one side of the truck to the other. Only the lower shock mounting bracket is side specific and it can be unbolted from the arm.
This is a '75 F100 radius arm I have that's going on a '72 F100, --just for visual comparison.
Thanks for the tip, are yours still uninstalled? A quick measurement would put my mind at ease.
From end to end, this radius arm is 28" long.
At the forward end (in between the 'tuning forks') is 3-5/16". Outside the 'tuning forks' is 4".
From the center of the large bolt hole at the front to the very tip of the threaded pin on the back end is 26-1/2".
After I've thought about this, I know the forward end of this '75 F100 radius arm is the same as an F250 because the endlink bracket for a Dentside truck that had the optional factory front swaybar from '75-'79 will fit all the radius arms on all '65-'79 F100 - F350 trucks. I have a factory front swaybar and endlink bracket on my '77 F100 I-beams/radius arms that came off of a '78 F250.
'78 F250 front swaybar and endlink C-bracket attached to the forward end of the '77 F100 disc brake I-beam/radius arm on my '69 F100.
If the F250 radius arm you have is 26-1/2" long, from the center of the large forward bolt hole to the tip of the threaded pin at the rear of the arm, then you would not be limited to donor radius arms from just the Dentside F250s. If the arm on your truck is the same length, donors could also include Dentside F100s and F150s --maybe even the F350s, if their dimensional lengths are the same as well.
This is 100% correct.. once again the forum stepped up and came through for me. It's under control now, I have a path forward...
I think I know the answer to my next question. If I have it this far down and I already have new steering linkages, the wheel bearings look like they were recently done. Should I do the king pins if they don't seem to need it ?? I'm already this far in??? The drivers side has a new caliper but it néeds a rotor.. why put new brakes on a ruined rotor??
Thanks again ultraranger
Originally Posted by ultraranger
From end to end, this radius arm is 28" long.
At the forward end (in between the 'tuning forks') is 3-5/16". Outside the 'tuning forks' is 4".
From the center of the large bolt hole at the front to the very tip of the threaded pin on the back end is 26-1/2".
After I've thought about this, I know the forward end of this '75 F100 radius arm is the same as an F250 because the endlink bracket for a Dentside truck that had the optional factory front swaybar from '75-'79 will fit all the radius arms on all '65-'79 F100 - F350 trucks. I have a factory front swaybar and endlink bracket on my '77 F100 I-beams/radius arms that came off of a '78 F250.
'78 F250 front swaybar and endlink C-bracket attached to the forward end of the '77 F100 disc brake I-beam/radius arm on my '69 F100.
If the F250 radius arm you have is 26-1/2" long, from the center of the large forward bolt hole to the tip of the threaded pin at the rear of the arm, then you would not be limited to donor radius arms from just the Dentside F250s. If the arm on your truck is the same length, donors could also include Dentside F100s and F150s --maybe even the F350s, if their dimensional lengths are the same as well.
Last edited by norvillebob; Apr 24, 2016 at 06:45 PM.
Reason: Spelling
If they are tight I wouldn't, personally. If you wait a while I should have a donor arm cheap off my 2wd f150, but I can't promise it won't be a month or so.
This is 100% correct.. once again the forum stepped up and came through for me. Its under control now. I have a path forward...
I think I know the answer to my next question. If have it this far down. I already have new steering linkages. The wheels bearing look like they were recently done. Should I do the king pins if they don't seem to need it ?? Mostly because I'm already this far in??? The divers side has a new caliper bit needs a rotor.. why put new brakes on a ruined rotor??
Thanks again ultraranger
You're welcome and I'm glad if I could help you broaden the choices of possible donor vehicles to get the replacement radius arms from.
....looks like your other radius arm wasn't too far away from giving up the ghost.
D5TZ-3A360-A .. Radius Arm / Obsolete ~ No Ford dealer or obsolete parts vendor has any NOS
1975/79 F100/150 2WD / 1975/79 F250 Regular & Crew Cab / 1975/79 F250 Super Cab with 6300/6500/6900/7500 lbs. GVW's.
If this is the case, then what I said about the interchangeability of the radius arms on the F100-F250 2WD trucks is true. --I don't know what the difference in the F350 2WD radius arm is/may be from an F100-F250 2WD radius arm(?).
I'm sure there are probably still plenty of good used radius arms available through an online wrecking yard parts locator. This is how I got the '71 F100 31-spline axles (from a '71 F100 w/9-3/8" rear end) I installed in my '69 F100 9-inch rear end. It's also how I got the '79 Bronco rear swaybar assembly to install on my '69 F100. --I went through Car-Part.com to get these items that were hard to find and weren't locally available to me.
If this is the case, then what I said about the interchangeability of the radius arms on the F100-F250 2WD trucks is true. --I don't know what the difference in the F350 2WD radius arm is/may be from an F100-F250 2WD radius arm(?).
The other 1975/79 F250 radius arm is: D5TZ-3A360-B = F250 Super Cab with 8,100 lbs. GVW; also F350.
The other 1975/79 F250 radius arm is: D5TZ-3A360-B = F250 Super Cab with 8,100 lbs. GVW; also F350.
If it doesn't list any specifics as to what the difference is in this arm compared to the others, it would seem logical to think, dimensionally, it's the same as the others. The main difference most likely is the threaded 'pin' on the tail end is probably a larger diameter.
The front end of the radius arms would have to be the same as all others, since the factory optional '75-'79 front swaybar (stabilizer bar) is interchangeable between the F100 through F350 models. In fact, the same 'C-brackets' (5C499 from the MPC diagram) for the swaybar endlinks used on the '75-'79 F100-F350 trucks were also still being used on the F350 DRW Super Duty E-350s through 1991. The swaybar endlink 'C-brackets' currently on my '69 F100 are ones I pulled off of an '87 DRW E350 Super Duty box van.
Econoline van swaybar assembly.
'75-'79 F100-F350 front swaybar assembly.
FYI, the 'C-bracket' (5C499 in diagrams) is not side specific. It will fit on either the left or right sides of the truck/van simply by flipping the bracket over.
I've done about all the sleuth work and reasoning of deduction I can do on this. If the threaded pin is 3/4"-10 on all, what is the specific (physical) construction difference in the D5TZ-3A360-A radius arm vs. the D5TZ-3A360-B radius arm?
I've done about all the sleuth work and reasoning of deduction I can do on this. If the threaded pin is 3/4"-10 on all, what is the specific (physical) construction difference in the D5TZ-3A360-A radius arm vs. the D5TZ-3A360-B radius arm?
I haven't the slightest idea, haven't seen either in person since the 1980's.
inre to post #11: D5TZ-5C499-A .. Bracket-Front Stabilizer Bar Mounting - R/L same / Obsolete
