Originally Posted by otr
I am finding some rust in areas behind the rear wheel wells, I would like to add mud flaps so that rain water is not thrown up into the various crevasses. The ones I see online look like they are for stock Dodge vans and the various RT fiberglass body parts will prevent mounting.
I prefer the universal fit rubber style flaps that are pretty commonly sold for pickups. They are flexible and and can easily be shaped and cut if needed, plus they seem to last a long time. We have had them on our 07 C190P Roadtrek for 10 years. Ours are sheet metal screwed to the fiberglass.
If you are showing rust at or near the bottom of the rear quarter panels, you may want to do a bit of further investigating and mitigation. Some vehicles, have a tendency to trap dirt and water inside the bottom of the panels at the bottom between the inner and outer panels. They also normally have drains to let any water out that gets in there. The drains often plug and hold water causing the very common bottom rust. Take a good look at the area for drains to make sure they are clean, and that the rust is not coming from inside and is truly just from rock chips on the bottom outsides.
In areas that get rock chips from the wheels, I have gravitated to using brush on pickup truck bed liner (I use Herculiner) on the areas. If properly cleaned up and prepared I have found it to be very durable for life and chipping. You might want to consider doing the bottom couple of inches where the damage your seeing is, even with the flaps.