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MJMarkhams70 · 08-06-2009, 10:51 AM

I posted an idea/question in our build thread in the overlander section. I have about 1/2" of frame sag in the rear half of our 27'. My plan of attack is to put jack stands under the front and rear of the frame and load the center of the frame to take the downward curve out. I am considering putting about 1/4" of upward curve to the frame. then I am going to box in the rear half to add strength and rigidity back to the rear. with the slight up curve, when the body and interior are all replaced, it is my hope that it brings everything back down to level and flat. I hope that made sense...

Thoughts/Ideas?

Michael

VIKING · 08-06-2009, 12:53 PM

It is not necessary to have a flat frame. It only needs to have the rear floor-to-shell connection built-up stronger.

Rich

PizzaChop · 08-06-2009, 02:10 PM

Michael,

To add to Rich's comment, the Airstream is built so that the shell supports holds up the frame and the frame supports the shell. There's a certain degree of flex which is inevitable and planned for.

The rear joint (shell,floor, frame-no separation) must be intact, the axles fresh, and the running gear balanced or you'll end up with the dreaded sag.

What typically happens with these older units is the plywood floor rots at or near the rear joint creates "play" between the shell and the frame. With old, stiff axles and rough ride, the joint gets slapped back and forth and at some point, something gives. (Usually the frame, then the shell.)

Just make sure your rear joint is good and tight. (see pic)

silverleeper · 08-06-2009, 02:25 PM

I did something similar to what your describing. On my 67 the frame looked slightly flexed just after the axle so to boxed in that area and the next section toward the back. I did jack up the frame a bit when I did the welding. A boxed frame is stronger but you still need the frame to flex.

Both Rich and Ron are correct about the frame. After years of wear and tear each frame seems to have it's own set of different problems. Good luck!

VIKING · 08-06-2009, 03:13 PM

mjmarkhams70, to add to my last post, when you are ready to attach the frame to the shell again you should level the frame by blocking up the back of the frame to eliminate the sag, then set the shell back onto it. If everything is done correctly the holes in the shell should line up with the holes in the C-channel again.
I reinforced my rear end(so to speak) by adding curved metal sections that wrap around the back corners from the frame rails to the last full-length outriggers. I bolted the floor to these and added two bolts through the C-channel into the frame rails, too.

Rich