How To: Quick and Cheap Mud Flap Replacement

turbofandude · May 1, 2014

The Back Story:
Walking to the truck one day, I noticed the back passenger side tailgate area was covered in dirt and mud, but the other side was fine. Upon further review, I realized I had one mudflap broken off. All that lime rock and mud on the unpaved roads near my girlfriend's house was getting catapulted from my tires. Long story short, I bought a generic set of mudflaps from Autozone (details below) and installed them. Sorry if the pictures are a little "eh", but I thought about making it a tutorial half way through - so I had to make do with what I hadn't already done (hence, there are no pictures of before - only during and after).

The truck in the tutorial is a 2006 Prerunner SR5.

The Guide

Here's what you'll need:

*A pair of pliers (to hold the nuts)
*A 13/32" (or equivalent) ratchet (a wrench or nut driver will do, but for ease, a ratchet)
*A 1/4" drill bit
*A market/pen/sharp object to mark where to drill your holes
*A set of 4 (or 6, details below) 1/4"-28 bolts and matching hex nuts
*A set of generic compatible mudflaps (the style I bought had a class/size, some don't - just do your homework on the size before buying, though they are kinda generic).

The flaps I bought were Power Flow 18x12's, available at AutoZone for around $12.99.

(Mudflaps not shown above. Also, ignore the needle nose pliers, I changed my mind on using them.)

The Process:
First, you'll likely need to remove the factory mudflap molding, as it is one piece. This can be done by removing the three 13/32" screws from the mudflap panel - one goes through the body molding and into the frame, the other two are directly into it (the frame).

Save these screws (put the upper two back in and kept the one that goes farthest down and closet to the center of the vehicle aside for later - we'll need it).

Then, there are three plastic pins that hold the molding to the mudflap panel (they are topped by the round plastic caps on the side of the panel). They can be removed by either: (a) breaking them off carefully (avoiding damaging the body molding) if you don't intend to use them ever again or (b) using fingers/pliers to push the self-expanding plastic arms back to the center and sliding out. I elected to take option a.

Once you've got all the screws and pins out and the factory flaps removed, it should something like this: (**NOTE**: do not get confused, I hadn't removed the screw I told you to leave out yet, as this was day two of this, since I didn't have the nuts the first night.)

Now's when the fun starts. You'll probably notice that the panel where the mudflap molding was isn't flat and a flat mudflap (which 99% are) will not sit flush - this is expected.

What we are going to do is this: we will put two bolts through holes where the plastic pins were. Then, we will put a nut between on them between the body and the frame - effectively holding them to the body. This creates a dilemma, however, as you don't want 55+ MPH wind pulling at your plastic body. This is why we saved that last screw, the one that goes into the frame. We will also attach the mudflap there, so that there is even pressure across both the frame and the body to avoid issues.

Now, hold your mudflap in the position you'd like it, making sure that it covers the entire tire spray region (mine almost didn't, be VERY mindful). Then, use your marking utensil to mark where you'll have to drill your holes in the flap to put our two bolts and screw in. I'd recommend drilling the upper hole, putting a bolt in it, and hanging it lightly from the hole, then finding the other hole locations. That will help you avoid the human error portion of holding a piece of plastic perfectly while hugging your tire.

Now, with your drill markings ready, drill a 1/4" hole in the mudflap at the correct locations. Once you're done, it'll look something like this (you can also get an idea for where the screws will be from this picture):

Also, be sure to use one flap as a template for the other - DON'T re-do the measurements. This will help with symmetry when finished.

We're in the home stretch! Now, grab one of the nuts with the pliers and slide it between the body and the frame, behind the plastic body piece (there is about a 1/2"-1" clearance, it is okay to push a little to make your tool fit, just be aware of what you're pushing). Line the nut up behind the hole you're going to be putting the bolt into, put the bolt through the flap, and do the deed. This process can take a few tries (and some swearing) as the bolt likes to move and it is rather hard to see. I ended up laying on top of the tire with my head in the wheel well to see it from the right angle. Do this for both bolts. With them in place, use your ratchet/wrench/nut driver to attach the mudflap to the frame at the screw hole. Once that's all done, give it a tug to make sure it's secure, and voila! You have a new mudflap.

It should look like this when complete:

Repeat this process for the other side and you're done!

When it's all said and done, mine came out like this:

Given another chance (and another set of mudflaps), I'd try to fix the angle they're at and lower them a bit, but they'll serve their purpose for the time being.

All in all, it was a cheap job (totaling at around $18, including the nuts/bolts and tax) and it took me around 30 minutes. I hope you guys enjoyed my first tutorial and that someone benefits from it. As always, I am open to criticism and new information. Happy trucking!