FJ Rocks pointed out some slight bulging on mine when we were getting ready to run Behind the Rocks in Moab. That was July 15, 2007. I did not check it after the next 2 days of wheeling, but there was very little bouncing/hopping. There was in fact lots of flexing.
Since then I did a run at Tellico (August 11/12) which provided lots more flexing and a little banging around, but nothing hard. When I saw this thread yesterday (Aug 13) I went to check my engine bay area again.
I now have CRACKS on both sides. They are breaks in the surface but not gaping cracks and run only on the vertical portion. Pics soon.
__________________ Rick C ~ ~ I aim to misbehave. 2007 GSJ15//Ti Ag//4WD AT All-Pro bumper, IFS skid, Extreme LCA links, LCA skids & Bandi mount Bud Built trans skid/crossmember/gas skid Metal-Tech step sliders OME 886/895 Total Chaos UCAs & spindle gussets Super Swamper 34" LTBs Warn 9.5xp/synth Demello rear bumper ACC Toyota Custom Tube Fenders Where Do You Want to Take Your Truck?
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I did some flex testing. You will have to excuse my garage tools. I hope this help shed a little light on the issue. I looked at the front body mount for compression and also setup a gauge mounted on one side of the body and used it to measure any deflection on the other side. Note that this test was done in a static environment. If you add dynamic forces the frame will most likely flex even more.
The test showed no flex in the body but 1/4" compression of the right bushing. this was with the FJ lifted 17" on the left front. I did not get the left rear tire off the ground which was my original intention but it was just to height to go with the high lift.
With additional lift of the left front to the point the where all weight is removed from the left rear may show additional bushing compression (there is not much left) and then start transferring the flex to the body.
The following picture show what I did.
Pre flex gauge
Pre flex left bushing
Pre test right bushing
First test at about 12"
Gauge
Left
Right
For the second test I loosened the bottom bushing on the right side to see if that would allow any more movement in the top. No additional space was noted.
Left
Right
For test 3 I took the right side up to 17"
Gauge
Left
Right
Jack Height
FJ From front
Left bottom bushing
Left right bushing
Summary:
This test shows torsion flex in the frame under static load. I did not even get maximum lift on the left hand side. With the rear tire totally unloaded and dynamic forces added there will be additional flex in the frame. The bushings will reach maximum compression and the forces will then be applied to the body.
This photo was taken on 5-14-07 when I posted up pics of my winch bumper install and was showing the solenoid box in the engine compartment.
And, this was discovered a few days ago when bernd contacted me and suggested that I check my FJ.
So, sometime after my winch bumper install and/or during my 5700 mile roundtrip to Ouray (and some other mild off-roading while out west), I ended up with the cracks.
But, who knows what specifically brought it about. The winch bumper? The long cross-country drive? A rut at Engineers Pass? A speed bump at Arby's? Or, maybe like others have already implied . . . . just good old fashioned repetitive flexing of paper-thin sheet metal.
These pictures should be at the Front Home page instead of the red 2008!!
How about picture of the month September Theme FJ Crack's
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