not sure about what range of years they fit, but this is who I found some thru, easy people to deal with...

Used Auto Parts Market

 

and here is why I needed to change the radius arms :-) ... got both installed this weekend, changed I beam bushings while I was at it...



Here is a test, can anyone tell which one is the bad one ? ha ha ;-)

 

Holy cow that's bad! All the ones I've ever had/seen look like the one on the right.

 

ha ha, I thought some people would appreciate that picture
;-) we have a little more rust issues up here in northern ontario than many other states would - I undercoat every year & drive infrequently in the winter, but the truck was driven full time for many many years & has paid the price !

 

Just for future reference, it is a 3/4 bolt that holds the radius arm to the I-Beam on a 79 F100, the original appears to be about 7" long, TSC has 6" or 8" seeing that the 8" had too much unthreaded portion (would have had to use spacers on underside, I tried the 6" & it left about 3/4" exposed thread once everything was tightened down, the original seemed a bit excessive (lots of exposed threads to get damaged & make changing coil springs harder) - no washers are needed, just the bolt & 2 nuts per side (as original).

 

Yes - but were any of the threads of the bolt hidden within the beam or radius arm once assembled? The reason for the longer bolt is so the load is placed on the shank/shoulder of the bolt rather than the threads. The threads are the weakest point of the bolt & where most failures occur. The original design seemed to be so all "mounting" or loaded portions of the beam & radius arm were against the shank of the bolt - not the threads.

 

Go to the want to buy thread