Better fender fasteners?

[dedmiston]

I'm looking for a better way to fasten my fenders to the wall. These sheet metal screws keep coming out. It's gotten to the point where I tighten them at every fuel stop, but they're so bad that I even lost one today in camp just because it's windy. Has anybody come up with a better option than these screws?

 

[John and Barbara]

Years ago a mechanic at Camping World (I hate to even say that name) told me to buy rubber base board material at Home Depot and cut small pieces for shims to fill gap between fender and side wall. make hole for screw. It worked very well, some gaps required two layers to fill gap, I used machine screws and locking nuts.

 

[Theunz]

Stainless machine screws and lock nuts has worked well for me. 8 or 9 years now without loosing any. A bit of Locktite would work with regular nuts if you want to go that route.

 

[LeftOverParts]

In addition to the screws backing out, we also have had the screw heads break thru the fender.

For staying put, there was a suggestion on this site to use silicone or caulk on the back side of the screw. This has worked but the hole in the sheet metal is small enough to still allow tightening. The thread lock or lock nut and new screws above sounds best.

For break thru, I’ve added a rubber faucet washer under the head.

 

[St. Michael]

I’ve used a truss head machine screw (10-24) with washer and nut on two RV. I put a rubber washer between the fender and wall. The truss head is much wider than a regular screw. I spray paint them black. You’ll need to drill out the hole slightly and I use lock tight because over tightening the nuts will crack the fender. Works great.

 

[dedmiston]

I had to fix this today so we could get back on the road tomorrow. We're hunkered down in Roswell, NM until this wind warning passes us by.

I consulted ChatGPT just for kicks and got a great suggestion. It suggested using threaded rivets and #10-24 machine screws and washers. I picked up this Threaded Insert Riveter Kit but they didn't sell the inserts at Harbor Freight. Luckily the tool came with ten inserts, which was exactly how many I needed.

These things worked pretty well. I should have picked up some Blue Loctite, but it's cold and I'm not going back out. I'll add some at our next stop.

I had to remove the fender first (not fun in this wind) and then drill out the holes to fit the inserts. Then I used the rivet tool to install all ten inserts. This gave me threaded anchor points for the machine screws.

Thanks for all your responses and ideas. They all sound like good ideas. Anything is better than those sheet metal screws.

 

[Mikendebbie]

I bought speed nuts for backup, reinserted the factory screws and put silicone over the back of the screw and the nut. That was summer 2018…no issues since.

 

[Daryles]

I put stainless steel washers under the heads to prevent cracking the plastic and rubber washers on the inside for the screw to bite into.

 

[Carl n Susan]

Speednuts and a touch of silicon have held my fenders on for over 10 years.

 

[RMcNeal]

What Carl said. Put a dab of silicone on the screw and it won't turn to back off.

 

[Jay & Bobbie]

After having a tire explosion last year, I found myself do significant repairs to the fender. The holes in the thin metal skirt had become wallowed out as well. I ended up replacing all screws with a larger self drilling screw used for metal roof. I happen to have plenty that color match the fenders. The screws have a rubber washer. I also added material to the back side of the metal skirt for additional holding strength. A dab of black silicone in the hole and sealed along the top of the fenders with Lexel.

 

[Freedom22]

When looking at a new 2025-2026 Montana I saw Keystone addressed this issue by reverse use of a nylon nut insert. I ordered these on Amazon and attached on the back side of the fender plus a dab of silicone. This has worked well for the last 4,000 miles. I have also used a fiber washer under the screw head feeling is was not as harsh as steel on the plastic fender.

 

[Billbored]

Interesting thread. Having same problem but fender is cracking. Any suggestions about repair/reinforcing the fender itself where cracked?
TIA for any suggestions.

 

[Carl n Susan]

Interesting thread. Having same problem but fender is cracking. Any suggestions about repair/reinforcing the fender itself where cracked?
TIA for any suggestions.

While a new Thread about repairing cracks is probably more appropriate, here are some hints. The Search function is your friend. Some finds using the Search terms "fender crack repair" are:

Fender skirts

What cheaply made items are these? Both skirts are breaking loose and some have pulled away thru the screws already. Has anyone came up with a better idea than these weak pieces of plastic?

www.montanaowners.com

Fender skirt repair

I just noticed the fender skirt is cracked on the side of my 2016 Montana that always gets the sun right above the front tire The crack is a perfect line that could be repaired from the back. I was thinking about applying a layer of shoe goo, the press drywall mesh into it and follow it up with...

www.montanaowners.com

Fender repair

For those that have had an explosive blowout, you can count on the fender skirting receiving damage. I had enough of the skirt left, although cracked about 80% of the way across, a few small pieces missing particularly where the screws fit into the recesses, and some smaller hairline cracks, I...

www.montanaowners.com

 

[jwengermt]

I used grommeted screws used for attaching steel siding and roofing on buildings. I used the ones designed for steel girts. Put them on in 2022 and haven't had any issues. The rubber grommet allows the fenders to expand and contract and counteracts the vibration.

 

[Billbored]

Susan, thanks for the response and direction to appropriate threads.

 

[David & Wanda]

I'm looking for a better way to fasten my fenders to the wall. These sheet metal screws keep coming out. It's gotten to the point where I tighten them at every fuel stop, but they're so bad that I even lost one today in camp just because it's windy. Has anybody come up with a better option than these screws?View attachment 2427632View attachment 2427633

I used small bolts with a washer against the fender and nylon lock nuts on the other side. Haven't had any problems since..

 

[DutchmenSport]

My approach is a little different, but still similar. My current Montana High Country fenders have been horrible. The screws are simply screwed through that plastic fender and into the aluminum J-wrap. Very few of them actually go into anything solid.

My problem is, the aluminum J-wrap screw hole breaks out. Once the first one started, the others followed.

My solution was to use a backer behind each screw. I used 1/4 inch plywood cut into lengths about 4 inches by about 2 inches. Then I placed these sheets behind each screw hole, added a washer to the screw (wood screw), and screwed it into the wood backer.

After that, I used a black colored calking and put a bead over the top of the fender where it touches the side of the trailer. Once that turned hard and bonded to the aluminum, the fenders have held fast. Occasionally, one will work loose, and I'll need to put a new back on it. But this worked well for me.... especially since the hole on the aluminum J-wrap is completely wrung out.