Frame cracks at the rear spring hanger?

[Tools R Us]

Working on DSRTRDR's '70 FJ40, the rear spring hangers did a good job of falling off. I haven't seen this before is it common?

Pictures in this thread;

https://forum.ih8mud.com/showthread.php?p=881011#post881011

 

[65swb45]

I've seen a couple of hangers crack, and a couple that bent, but not a cracked frame. IMO, there was prolly a preexisting flaw in the metal of the frame that could have been found under a thorough examination. Who the heck cares tho, as long as you fixed it better than you found it, which it more than looks like you did!

I recently reinforced my rear spring hangers both sides with a single vertical plate gusset, rather than a box like yours. I wanted the plate so that I could have abolt on anchor point for the back of my rock sliders.

I've also seen where the hanger is braced to the frame from the leading edge, with a plate extending down in such a manner that it covers the front of the hanger, acting as a cover for the spring, and a skid to help the rocks on their journey away from the frame and under the springs!

And tell Claudia to invest in some U-bolt skid plates! I might know where she can find some!

 

[DSRTRDR]

shameless self-serving plug, Mark ;p ;p ;p how about a U-bolt reversal kit rather? if only you were taking credit cards or PayPal......

I can't remember having hung up on U-bolt plates (no new bends since I got the truck) or diffentials much at all. I rather suspect it could have been from dropping down obstacles in Moab, or the whoop-de-doos caused by ATVs on some trails in AZ, which really got the truck creaking..........sort of the twists you see in the picture.

I think that material fatigue just gave in when the truck was finally wheeled some (after having mostly been towed behind a Class-A-RV to Baja to get around with a wife that didn't quite like the cruiser according to the PO). When we cleaned the frame and worked on the truck over the summer, we did not detect any indication of stress fractures, let alone cracks

I was lucky I found them while airing down before getting on the trail; just two days before, we had been out wheeling, and went back some 100 miles at 75-80 mph . I am sure there were some cracks present already then........on about three occasions I heard some strange noise I couldn't identify or deliberately reproduce. I can only imagine...........

In fact, a search here and in the FSM revealed that Toyota apparently anticipated this could happen and provided instructions on welding frame cracks; go figure.......(honestly doubt engineers in Nagoya would have known Moab trails back then.......)

This is how my year started Janaury 2.........

 

[honk]

Wow! That was close! I'm imagining the extent of damage you might have suffered if that hanger had caught on something solidly at any sort of speed. It might have ripped back, tore the axle loose, and sent you flying while the truck flipped or set down and tried to come to an instant stop.

Nice fix. It DOES look like the recommended type repairs as seen in the early FSM's.

Did you measure the thickness of the frame steel after buzzing off any surface rust? I worked on a guy's truck once, a Ford (so as not to imply any cruiser failing), that had that same sort of appearance to the frame metal. Kind of mottled brown dusty looking. It wasn't rusted through, and it didn't have any areas that I could see where the steel had flaked away in a sort of crater as I've seen on other things. But after taking it to bright steel on each side what was left measured just over 1/8" (.125) when it had originally been 1/4" (.250) That truck had long areas of both frame rails at the back that miked to only half the design gauge and still looked fairly normal. It was a truck that had spent it's twenty five years in California's central valley at Madera. Not a lot wetter than most of Arizona.......well, maybe wetter than the worst of Arizona It was a sort of slow overall even erosion, I guess.

 

[Tools R Us]

...Did you measure the thickness of the frame steel after buzzing off any surface rust? ...

The first pictures are dust stuck in a rust preventive oil. I will measure it in the morning, it isn't bad, 3/16" maybe? I don't know what the original thickness was?

 

[Mark W]

I've seen this a couple of times. Exactly the same spot and same type of crack. But in both cases we caught it long before they progressed that far.

Mark...

 

[honk]

The first pictures are dust stuck in a rust preventive oil. I will measure it in the morning, it isn't bad, 3/16" maybe? I don't know what the original thickness was?

It's 3/16" or more likely a metric size that's in that ballpark.

 

[Tools R Us]

It's 3/16" or more likely a metric size that's in that ballpark.

It's between .179 and .188" across the cleaned area, 5 mm is .197" that maybe the original thickness?