Plastic

[Gubs]

Anyone else have problems with the fenders breaking around the screws? I’ve got fenders coming off since the screws are breaking through. I’ve tried to reinforce with metal washers but that just made the holes bigger!

[Foldbak]

Fender skirts have always been a problem on every brand.

[mtheo]

I have had a few break, put washer on and then made sure to silicone the fender on. The silicone will holder even when the screws back out, at least for a little while. I check them almost every morning on long trips.

[mlh]

What I’m wondering is, could the tires be out of balance causing the camper to vibrate and breaking the plastic. People do have problems with the fenders but not like this. What I would try is balancing the tires if you haven’t already then putting small bolts and nuts with washers on both sides. Use nylock nuts and don’t tighten them too tight. You might try as someone suggested putting some silicon under the fender.
Lynwood

[DutchmenSport]

I encased mine with clear silicon for the same reason. It's packed full under the fender against the wall. Also, I used larger washers, and I also had to put some kind of backer on the screws that screwed just into the metal J-panel.

About why this happens? I don't think it's trailer vibration. No matter what you do, your trailer is going to bounce when going down the road. What causes this is the wind blowing against them. They hang down, the wind makes them wiggle back and forth. In time, the metal wears thing (think of bending a wire over and over again until it breaks) and then the plastic or vinal simply gives way. Add heat, cold, and sunlight (UV rays) attacking those plastic things, and it's a wonder they hold up as long as they do.

Any "plastics" on your camper will simply give way after some time. It just can't hold up to the UV rays. Look at the vents and vent covers on your roof. In time, they loose their color, get spotted with grey, and eventually crack and fail too.

No, I disagree.... it's not because of the tires.

[Daryles]

Stainless steel washers under the screw head.
Dab of silicon over hole.
Put the screw in, not too tight.
Dab of silicon on the screw threads sticking through the inside of the skirt to prevent them from backing out.
Silicone the joint seam to thr skirt.

[Lee-CI]

Saw a video a couple of months back very much along the lines of Daryl's post. Now I can't find the darn thing. Been intending to do this as a preemptive strike. Should probably bump this up to the top of my to-do list

[432bartman]

Yeah I went through that and replaced everything with SS bolts and nylon lock nuts. You just can't over torque them.

[John and Barbara]

Rubber base board material like you see at bottom of wall in hospitals and offices. Material can be purchased at Home Depot or Lowes. Cut small pieces and drill hole and use as spacer between side wall and fender. Learned this from a RV mechanic years ago when I was buying replacement fenders for a 2007 Grand junction. Worked great so I did same with our 2019 3121 and not one crack. I also used black stainless 10-32 screws with aircraft lock nuts. Do not over tighten.