I have a 1995 4X4 f150 reg cab. just recently installed 6 inch lift and 35" tires. since then after replacing the drop brackets for IFS, coils springs, shocks and radius arm drop brackets, installed new bushings for radius arms at the time of install, the shock towers both rotted away got replaced and then a few months later pulling out of a parking lot i snapped the threads off my radius arm, changed the drivers side radius arm and drove the truck for a few more months and now snapped the same thing on the passengers side.. I haven't snapped a new radius arm yet both were the old ones and seemed to maybe have been cracked previously by the rusted area you can see where it snapped..

Has anyone else had this problem or heard of this issue? I cant seem to think what could be the issue, also when the truck goes in reverse the tires tow in tremendously and i was told thats because the way the IFS flexes and twist when in reverse, they straighten back out when going forward again.. was my nut on the radius arm not tight enough causing play, they were torqued to 200Ft. Lbs or maybe to tight..
thanks to anyone that can be of assistance

 

I could see them breaking from rusting out, if you could post a pic of the broken parts maybe we could tell. There really isnt that much stress on a radius arm during normal use.

 

you can see some of the surface area is rusted meaning its been weakened and broke for a while and the middle of the piece was the fresh broken look, i thought maybe it was because they were just old and weak.. its just weird to me both happened just turning on pavement not four wheeling the truck.

 

The torque for the nut on the threaded end of the radius
arm is 90-120 ft. lbs.