The front wheels forward and backward force is suppose to be controlled by the side support rods. Where these are attached to the axle, the bolts and axle holes become wallowed out. That stress is then transferred to the center pivot pin. My threaded area in the support (which are soft steel threaded) then become hammered out (Mine 1/8"
You can check this rocking action , by jacking up the front and putting a rod thru the vertical holes and puling forward and back.
Solution check above. Remove pins of support rod to axle Shim and replace bolts.
Results will help center pivot pin and mount failure.
I had to pound my pivot pin in 1/4" and am now thinking of tack welding it below fan area