Kenworth Frame bending

You don't have the end piece at the end of the frame rails, might be why it looks like your missing a crossmember?

 

I've looked at this thread a few times. Call me blind but I'm not seeing anything seriously wrong with the frame rails. Could just be because I'm viewing the photos on my phone. The only thing I see is the rust jacking along the 5th wheel which isn't a super huge deal. Knock the bolts off, clean off the rust and bolt it together with new grade 8 fine thread hardware.

 

That end piece is not standard equipment on a Kenworth. We have a whole yard of KWs without that piece. It's not really structural.

 

No it's not structural, but it creates an illusion. That's all I'm referring to.

 

This layer of rust from the 5th wheel mounting frame was strong enough to stretch bolts to the breaking point. You will find it has the power of hydraulics. And as @NorthernMechanic said I can't see what is flexing or bending. But it will be interesting what you do find, sometimes we learn from each other.

 

I know this is an old post, but looking at the pics, I did not see any spacers between the freightliner hangers and the frame. We have installed freightliner suspension under several trucks, but ALL of them I have messed with have had 34 1/2 in frames instead of the 34 in frames on any paccar truck, we just use 1/4 in steel for spacers. That is for later model freight liners frames, the older ones like mine has 33 1/2 in frames, so I have 1/4 inspacers on it to use the pete air leaf. I am not sure if they made any in between that had the 34 in frames, I have never seen one.
I could see a problem if one just installed it and scrunched it down, something would have to give.