Airbagit Tow Kit 2008-2012 Ford Super Duty Dual Rear Wheel 4 Link - Manual (Page 4)

11. The inside of the frame needs a little bit of trimming before the upper bag mounts
can be put on. Use a cut off wheel or a plasma cutter to cut a straight line. Trim the
inside lip of the frame so the bag mount will fit flush against the bottom of the
frame
12. Align the 3/8” diameter hole on the bag mount with the with the original bump stop
mounting hole on the frame. Not all frames are the same and there are 2 different
holes on the bracket to choose from. Make sure that the bracket sits directly over
the centerline of the axle. Mark and drill the remaining holes and attach the upper
bag mount. The pan hard mount on the driver’s side of the truck utilizes many of
the same mounting holes so be sure to install that before all of the hardware is
tightened.