My FJ60 has a fully boxed frame, PO replaced the C frame with fully boxed.

[hickuptruck]

I've had this FJ60 for more than a year and a half now. I bought it like this, and it has always been a salt belt and Northeast Cruiser, meaning salt. What do you guys think? I think PO had an ARB rear bumper, but sold the bumper to fund the rear C to be replaced with a fully boxed section due to rust. Another clue is that is that I think it has OME heavy leaf springs. I think the C part of the frame started rotting out on the PO.

So what's your opinion on Fj60s with replaced fully boxed rears? Does it ruin the ride because there is less frame flex? Does it look to be a job done well? Looking to add a rear bumper in the future, so what are my options? I would prefer a bolt on bumper but that probably wouldn't be feasible since I wouldn't be able to weld a capture nut right?

 

[MarkBC]

I hope there are drain holes in that box...

Looks like the rear tire carrier cross piece was removed? That will remove some stiffness. It will also be hard to put it back on since the box will prevent you from using the nuts and bolts.

Also it looks like the rearmost frame cross section that the stock bumper bolts to is removed. That will also remove stiffness.

Unless the bumper you are planning to put on has a lot of stiffness it looks like you will lose some strength there; somewhat made up by the box frame instead of C frame.

Maybe it's just me but I don't want my frame to flex since that will flex the body too. IMO the suspension should absorb the flex. But I'm no expert on that, esspecially with leaf springs.

 

[sedonut]

I would think it would change both the flex and the strength of the frame. As you have already bought it I would just go with the frame is probably stronger and enjoy your truck.

Would I spend a fortune restoring it , no. But it is a north eastern truck. Don't over think it.

 

[GarrettS]

Honestly, it’s probably super good enough and not worth overthinking as @sedonut said, but you may want to look into installing a replacement rear cross piece or fab something to replace the rear cross piece that @MarkBC pointed out.
Maybe just a cut of C channel bolted and/or welded between the frame rails?

Maybe the box accounts for the stiffness/sturdiness the rear cross piece provides, but I would think you would still want something sturdy joining both sides of the frame there in the back of the truck.

 

[GLTHFJ60]

I boxed mine in 12 years ago. It's great

 

[open country]

All else equal, boxing would add strength over c-channel. I would find a way to make sure there's not rot within the c-channel behind the new plates, as in the previous owner didn't just cover up the classic rear frame rot, if not then seems great to me.

 

[SteveH]

Boxed frames are ok until/unless they get full of dirt, water, and salt. I would squirt some oil or 90wt. inside that boxed frame and let it run out (preferably not over your paved driveway). You might put it on a lift so you can see better, and perhaps use Fluid Film or a non-runny grease and do it that way, too. As long as they did a decent welding job and there is no significant corrosion, you should be fine.