Custom Mud Flaps for the Tow Vehicle and Oliver

[jd1923]

After spending considerable time and money to get our Oliver cleaned, stripped, buffed and ceramic coated, and all exterior trim painted or replaced, I figured is was time protect our major investment!

Our TV had bolt-on 12x18" rubber mud flaps which were not nearly wide nor long enough to adequately protect the Oliver. On our camping trip last summer, we hit some mud in the grasslands of North Dakota and the entire lower front and rear bottom of the Oliver were packed with MUD!

The TV is most important, to protect the Oliver front, so I started there. I looked for mud flaps that would fit and soon decided to get stock material that could be cut to size. I purchased this product. It's a poly non-rubber material 0.15" thick. It could be a little thicker but I like how it holds its shape and position, not flopping around like rubber. I purchased this huge 24x36" set made for semi-trucks so I had enough material to cut both TV and TT mud flaps! All for only $19! You could find better material but so far so good and now that I have worked this project, replacing the material in the future would be easy enough! 😎

https://www.amazon.com/dp/B06XRHB7GH/?th=1

I removed the original mud flaps, used them as a template and I added 3" in both length and width (1 1/2" wider inside and out). On the curbside, I had to make a large oval cut-out the the tailpipe. Because the new flaps are wider I cut a curve on top to blend the flap the the truck body (see pics).

[jd1923]

I understand most of you have good mud flaps on your TV, but on your Oliver?

@John E Davies installed some on his Mouse back in 2018! Craig @Galway Girl did a similar installation more recently and maybe there are others.

In the designs I've seen, the mud flaps were mounted behind stabilizer jacks where there is a frame cross-member, an easy place to bolt a horizontal mount. I was not happy with this design as it does not protect the full underbody behind the wheel, nor does it protect the stabilizer jacks from taking mud. My goal was to install a mud flap between the rear tire and the jack, but there’s only about 3-4" or space!

I realized that with a fitting 90 bracket I could use a frame bolt for support. I removed the 3” carriage bolt that holds the rear of the steel suspension subassembly to the main aluminum frame. I purchased #5 ½” bolts, 3 ½” long to be a ½” longer allowing for the 0.4” depth the the HD counter bracket. After an hour and a half searching Amazon, I found these which turned out to be perfect! I got the 6x10” brackets, where the 10” length ends just inside the width of the wheels.

https://www.amazon.com/dp/B095NRB6N4/?th=1

I used the stabilizer jack to get the rear axle up on a jack stand (placed under the plate centered between the leaf spring U-bolts). Then I removed the wheel and the base of the jack stand to allow for ample work space.   

Each side of the brackets has 3 predrilled bolt holes. On the 10” length, they’re perfect to mount the flap. On the 6” length, I got lucky! The center hole is just in the right spot to mount to the frame bolt. I drilled the center hole wider to ½” and bolted it in place tight enough to hold the angle. Then I used a digital caliper to get the bracket perfectly level to the frame. I used a 5/16” drill bit, the size of the existing holes, to scare a center, then switched to a ¼” drill bit which is the correct size for a 5/16”-18 tap. Drill through both the steel sub-assembly and the aluminum frame. I used a little cutting oil to make the drilling and tapping go easier. Then added Grade-8 5/16” bolts which I had on hand with blue thread-locker. The ½” bolt has a Nyloc nut. Torqued them down by feel with ratcheting wrenches and this HD bracket ain't going nowhere!

Edited January 17 by jd1923

[jd1923]

Next step; cut stock for the Oliver flaps. The stock was 24x36" so I cut every flap sideways making them all 24" long to start. I cut the Oliver 13 1/2" wide to stick out 1" beyond the tires and I made the area under the mounting bracket a 13 1/2" square which made the mud flaps sit 4" off the ground.

It's too difficult to work with the full length of stock when cutting a pattern to fit around the curved body of the Oliver. So I cut a piece of cardboard 13 1/2" wide like the flap and 10 1/2" tall, the measurement from bottom of bracket to the top. I drilled the 3 mounting holes into the cardboard for alignment.

I used the little curvy tool (stocking stuffer from Chris a few years back), took a few measurements and started to cut away at the cardboard making the opening longer and wider. I wanted at least 1/4" clearance above the fender and 1/2" below, so not to touch and to allow for cleaning the fiberglass. Another cut to follow the pattern of the inside wall until the cardboard was perfect. Then traced it onto the poly stock and cut some with a razor-knife and the sideways tin snips worked very well. Used razor blades, a grater block and files to clean up the edges, and voila! 😎 

Afterwards, I traced the finished mud flap onto graph paper so I can share my template with our Oliver friends who would like to copy the design!

Edited January 17 by jd1923

[jd1923]

I cut the base of each rear stabilizer jack to have one flat edge. This allows more room for the flap to arc rearward while towing and so the flap material is not always hitting the same point on the arced edge. I don't believe the strength of the part was reduced much and these parts are readily available. I already have one spare!

Use a 10" steel cutting blade on a chop saw and this is quite a strong piece of metal. By the time it cut through it had melted a ring into the plastic plate below. Filed the edges smooth on my bench grinder and steel brush. I may hit the open edge with spray paint later.

So, the right side is done and I'm very happy with it!  😎  Several views to follow...

[jd1923]

Time to repeat for the other side! Common thinking and my first thought was that I could turn the template upside and trace the mirrored view for the other side. Good thing I thought to measure twice. I positioned the cardboard stencil made for the right side and found I had to drill the holes about 5/16" lower for the left side. Who knows why except that only OTT could do so! Was a simple fix to adjust the drill hole placement, and otherwise the pattern flipped over was identical.

Pictures show the streetside and how the jack fits with Andersen blocks, and the view from the rear showing both mud flaps (bumper off for polishing). Boy, I used to hate cleaning the road tar, grease and grime from under there! No more, just pressure wash the mud flaps! 😎

 

Edited January 17 by jd1923

[jd1923]

No more dirty Ollie! 

Edited January 17 by jd1923

[jd1923]

It took a couple days labor, but I take my time and enjoy the work!

$50 in parts for both truck and trailer, you can't beat it. 😎

Edited January 18 by jd1923

[Geronimo John]

On 1/17/2026 at 12:23 PM, jd1923 said:

Time to repeat for the other side! Common thinking and my first thought was that I could turn the template upside and trace the mirrored view for the other side. Good thing I thought to measure twice.

In our trailers there is very little that is level, square or symmetrical.  And it is amazing how well it is done.  

When Art and I were making front wardrobe shelves for our OE2's, I "Ass-U-M'ed" that the template for his would work in mine.  Nope.  I failed to remember the above mantra.

GJ

[topgun2]

10 hours ago, Geronimo John said:

Nope.  I failed to remember the above mantra.

Duh!😁

[jd1923]

One week on the road. Besides 700+ miles so far, we’ve run 30+ miles on washboard dirt, and through some muddy washes too!

No dirt on the rear lowers and no splatters front of Ollie due to the wider TV mud flaps! 😎

[taylor.coyote]

JD,

Mud flaps have been on my  to do list for along time. I was planning to install John Davies design but your idea looks to be a bit less effort for instalation and appears to provide protection up into the wheel well.

The clearance between the flap and the tire appears to have a small clearance. My concern: I have been caught by a storm on dirt / clay roads with not rock top dressing.  The road surface stick / wraps a couple of inches of clay around all the tires. Does your design have enough clearance to accommodate this extreme situation?  Hopefully, I will not be caught by these road condtions in the future but want a design for all conditions. 

[Tom and Doreen]

8 hours ago, taylor.coyote said:

J I have been caught by a storm on dirt / clay roads with not rock top dressing.  The road surface stick / wraps a couple of inches of clay around all the tires. 

I feel your pain!  We headed down a dirt road  to visit Toadstool Geological Park NE a day after a rain ( without the trailer luckily ). The mud was sticky and slick all at the same time, completely filled the wheel wells and turned the tires into slicks.  We paddled in 4WD for miles.  Later the slurry dried nearly to concrete consistency!  Weeks later I was still washing bits and pieces of the stuff out from under the truck! 

[jd1923]

14 hours ago, taylor.coyote said:

Mud flaps have been on my  to do list for along time. I was planning to install John Davies design but your idea looks to be a bit less effort for installation and appears to provide protection up into the wheel well.

The clearance between the flap and the tire appears to have a small clearance...

Taylor, I just measured it to answer your question. At the closest point, bottom of the L-bracket, the clearance measures 1 1/2". When you see 3-4" of caked mud, how much is actually above the tread? Most of it is in the treads and caked around the side. I've had my truck wheels caked up but not so much on the trailer. This doesn't worry me.

And below the rubber/plastic flap material bends outwards while towing and no big deal if it got damaged. It's so easy and cheap to replace if need be.

John E. Davies did an amazing amount of work to his "Mouse!" I studied most of his work 3 years ago when I first joined The Forum! But sometimes I'd asked, why would I need this? Or why this particular design? I imagine half of you reading think the same about some of my many mods and that's fair. Coming from the airplane industry he worried and over-engineered more than I would. Three years since, I've reworked about all I can think to do on our Oliver! 🤣

In the case of mud flaps, I believe my design is far superior for at least a couple reasons. The mud flap in his design is a full 6" further back. The 6" of open fiberglass will be hit extra hard since dirt and stones will hit the mud flap and bounce upwards due to the rotation of the tire. The open area will get chipped and be doubly hard to clean. And next mud episode; do you want your stabilizer jacks packed with mud or protected behind the mud flaps? 

We've had 49 overnights since this upgrade, on a bunch of short trips this year. They still look like new. I wouldn't change anything. Anybody who wants to copy my installation, send me a PM with your mailing address and I'll mail you a paper template to make cutting the mud flap material easy. Everything else you need is explained above in this thread! 

[taylor.coyote]

JD, thank you for the thoughtful reply. I do like your design. In 7 years of owning our trailer getting caught in the out-back Owyhee country in far south eastern Oregon has been a one-time event. In fact the mud/clay wrapped the tires and the truck tires were standing on an inch or two of mud/clay above the tred. The truck hardly would respond to turning the front wheel and would genneraly  plow straight forward, eventually moving the direct they were turned. Fortunately we were traveling on a slight down slope most of the way to gravel topped roads.  Even in 4 wheel drive, I don't think we would have enough traction to climb more than a modest grade.

All this said, I think I will likely forward with your design because the we avoid this kind these type of roads if rain is in the forecast. Regardless of the rig you are driving, these roads become virtually impassable when saturated. Side slopes are the killer.