Class C Mudflap Replacement

[Chateau_Nomad]

Evidently Thor didn't tighten the bolt/nut holding the driver's side rear (front of tire) mudflap very securely. At some point the bolt fell out and allowed the flap to be sucked back in contact with the dually tires. This flap protects the propane bay from debris thrown up by the rear tires.
It didn't harm the tire, but the polymer mudflap didn't fare too well...


I found a suitable replacement on Amazon (2 for $20) which was actually a little thicker. However, the replacement was too wide... but scoring and snapping it with a utility knife was easy... just like a piece of gypsum board!




Of course the holes didn't match... that was as simple as matching up from the holes on the old one and drilling new ones.
A trip to the hardware to get new self-tapping screws, fender washers, lock washers, bolts and nuts. The original install didn't have the fender washers or lock washers... but I thought that was a good idea.


Actually there are only two self-tapping screws holding the top corners... I show 3 in the pic.
Drill the holes...


Then install using a 3/8" socket & adjustable wrench to tighten.

[waynetaylor55]

Nice work!

[jabrabu]

What is the bottom edge of the flap secured to?

[Bob Denman]

https://www.thorforums.com/forums/at...1&d=1625658515

[Chateau_Nomad]

Originally Posted by jabrabu

What is the bottom edge of the flap secured to?

The lower bolt, down about midway and slightly off center attaches to a couple "cross braces" behind the flap. I'm pointing to the hole I drilled for it in one of the pics. They aren't as sturdy as I'd like, but they seem to do the job.

The flap is a stiff polymer material, not flexible rubber. So it doesn't wag the way a rubber one would. Probably best too... I'd rather sacrifice it than a tire... as shown in the pics.

[jabrabu]

Originally Posted by Chateau_Nomad

The lower bolt, down about midway and slightly off center attaches to a couple "cross braces" behind the flap. I'm pointing to the hole I drilled for it in one of the pics. They aren't as sturdy as I'd like, but they seem to do the job.

That's where mine failed -- at the lower brace. Mine just had the horizontal brace, not the vertical brace, and that brace is just screwed into the inner wall of the coach with a couple of sheet metal screws. Those screws rip out and the flap then rubs on the tires. I ended up using wire and zip ties to attach the bottom of the flap to the chassis frame. I have owned two Chateaus, and they both had this same issue. It is a poor design.

[Chateau_Nomad]

Originally Posted by jabrabu

That's where mine failed -- at the lower brace. Mine just had the horizontal brace, not the vertical brace, and that brace is just screwed into the inner wall of the coach with a couple of sheet metal screws. Those screws rip out and the flap then rubs on the tires. I ended up using wire and zip ties to attach the bottom of the flap to the chassis frame. I have owned two Chateaus, and they both had this same issue. It is a poor design.

Agree with the poor design... looks like an afterthought! I think a couple sturdier vertical braces forming a box shape would make a more durable support.

I replaced that bolt assembly on the passenger side too. I added decent sized fender washers front and back of the flap, and also added a lock washer to hold the nut tight.

Hmmm... maybe I'll give both a little dab of blue Loctite - because that nut falling off was where mine failed.

[Elite Washington]

Mine did the same thing, need to still replace them

[Pete'sMH]

Mine did it and I emailed a photo to Thor and they sent me a complete set of replacements without any fuss. They got to my house before we got home from a trip. I made a few modifications to the mounting engineering and never had another problem.

[Chateau_Nomad]

Originally Posted by Pete'sMH

Mine did it and I emailed a photo to Thor and they sent me a complete set of replacements without any fuss. They got to my house before we got home from a trip. I made a few modifications to the mounting engineering and never had another problem.

How old was your rig when it failed? Silly me... I just ASSumed since it was out of warranty that it was my responsibility.

[Wiley1]

Mine did the exact same thing. But my propane tank is in the front, nowhere near the dualies. I was able to fix it by drilling a new hole and using a stainless steel sheet metal screw.

[Connieb]

Mine did it too, but it was under warranty. Dealer just put a new bolt in. I found another dealer.

[bry899]

Mine failed the first trip we took. We smelled a burning smell, pulled over and removed that half worn mud flap. Never replaced it as it appeared to serve no purpose. My propane tank is not that close to be protected by it. 15,000 miles with out it. No issues. My propane tank is closer to the road then the tire.

[plastrd]

I tried to patch mine up a couple weeks ago but they already broke free again. You can see the original hole the self-tapping screw into the side wall went into was worn into a slot and eventually broke through into the wheel well. The second screw apparently fell out some time ago.

I tried pulling it forward and putting the screw into some fresher sheet metal but it broke out of the new hole within about 2 weeks. It's actually pulling the horizontal cross brace into the tire since it's mounted on that side of the flap and the friction has sharped the inside end of the brace into a sharp edge! The outboard part of the flap has a hole worn through where it contacted the tire.

I think I need to replace the whole thing and rig up the extra vertical brace in the second set of pictures.

Do you happen to have a link to the 2/$20 mud flaps you used for this project?
This listing looks pretty similar but they come in a few sizes so I'd like to start with the same ones.
Buyers Products Polymer Semi-Truck Mud Flaps - Pair, 24in.W x 18in.L, Black, Model Number RC18PPB

[Chateau_Nomad]

Here's an Amazon link to what I purchased. You only need to cut one edge... actually score it with a utility knife, then snap it off.
Buyers Products Polymer Semi-Truck Mud Flaps - Pair, 24in.W x 18in.L, Black, Model Number RC18PPB

Let me know if you need any more detailed pics... I'll do my best.

[bry899]

There is a reason why you don't see mud flaps in front of tires and trucks.

[plastrd]

Ordered up those 24x18 mud flaps and cut them down to the same width as the originals by scoring and snapping.
This is on the passenger side since the driver side one is still holding up for now. I wasn't quite sure how I wanted to handle bracing so it wouldn't just get blown back into the tire again. The side wall is all rusted and destroyed from the original cross brace having been screwed into it and pulling out a couple times.

The original flap had only an inch of overlap with the vertical wall it was screwed into and with the screws so close to the edge, it was basically just a hinge that let the flap.. well, flap. Keeping the screws in the same place but adding 4" of overlap by sliding it up allows the flap to help brace itself and I turned the cross brace vertical for extra rigidity and put a third screw through it into the wall.

With it all reattached it feels much more solid and difficult to pull back toward the tire. It ends now at the bottom edge of the wall instead of several inches lower which lowers the wind profile that would push it back as well.
Hopefully this holds up but if I see it flexing, my next step is to replace the brace with a fresh piece of thicker steel and/or add some angle iron to brace the brace.