If you wheel a 2nd Generation Trooper with mud flaps this will happen to you sooner or later.
The Mud Flap tears off it's supporting plastic, sometimes all the way up to near the top of the flap. The attachment at the top is quite stout, so the Mud Flap can flap about quite a bit and not fall off. That can be annoying at speed, and it looks unsightly.
Here is what it looks like from underneath.
You can see that it tears right along the thin seam where the brace joins the flap.
Rather than replace the Mud Flaps with new, and just have them break the next time I go wheeling, I decided on a cheap fix. First measure about 2 1/4" in from the inside edge along the line of the brace.
Drill 2, 1/4" holes 1/2" above and below the mark.
Fabricate a tool out of wire something like this.
It's a tool to insert rubber bands into the holes.
Place the Tool with the rubber band in one of the holes and pull the rubber band partially through the hole.
Remove the Tool and insert it in the other hole and hook the other end of the rubber band, and pull it through. This leaves the open ends of the rubber bands on the brace side of the flap.
Hook one end of the rubber band over the brace.
Then the other.
Depending on the strength of the rubber bands repeat. I have used 3 here.
With the rubber bands installed, you can see how things deflect when a strain is placed on them. If I pull the flap back much more than this, the brace will bend enough for the rubber bands to come off the brace. The same thing will happen if you catch the Mud Flap when wheeling, at the end of the day just reattach the rubber bands.
Every now and then the rubber bands will have to be replaced, since they don't take weather well. The rubber bands hold the Mud Flap in the stock position quite firmly even at highway speeds.
Update, a new and improved attachment method