Ford F350 Cracked Frame
On our last trip with our rig, I noticed one of the front bolts attaching the airbag on the right side had broken off and the mount was significantly bent. I let the air out of the bags for the trip ...
Forum Discussion
HMS Beagle wrote:I fully agree with that.
There is another engineering issue with typical air bag mounts not mentioned above. Some of these mounts cantilever out from the C channel frame (the newer ones not as much). This puts a twisting stress into the frame channel. If you look at the spring attachments, they are also cantilevered out so what's the difference? Usually there are cross members placed right behind or very nearly behind the spring mounts. These cross members resolve the twisting stress produced by the spring mounts. There are no cross members where the aftermarket bag mounts attach.
The Ford engineers aren't stupid (well generally speaking anyway :)), but they cannot engineer the frame to allow for anything some aftermarket supplier might think up. The problem is that the aftermarket suppliers very often do very little engineering at all.
On this particular F550, no air bags were being used. It was a well drilling truck, with leveling outriggers at the rear of the bed. The upward pressure of the outriggers on the tail of the frame induced a downward force farther forward on the frame, above the axle. The frame cracked at it's weakest point, where the scallop is located. The frame web height is also shortest above the axle.
