M-MAX Fender Flare Instructions



Tools Required:

  • 10mm and 11mm wrenches (recommended: ratcheting end wrench)
  • Pliers
  • Phillips Screwdriver
  • Permanent marker and/or small right-angle pick
  • Razor blade/box cutter
  • Drill & bits (recommended: step-up drill bit)
  • Safety glasses
  • Angle grinder and/or reciprocating saw
  • Grinding wheel, or metal file
  • Hammer
  • Wood or metal block (for pounding a 90° angle)


  • Sandpaper, sanding block and/or electric sander
  • Body filler (such as Bondo©)
  • Waterproof caulking, or metal filler
  • Masking tape
  • Spray can of rubberized undercoating 


We recommend waiting to paint the M-Max Fender Flares until after they have all been fitted to the body, because the most accurate fit may require some sanding of the flares …so ignore the fact that the flares in these pictures are black.

We also recommend washing your vehicle thoroughly (including the wheel wells) before starting this installation.

Front Fender Flares

1. Remove stock fender flares (10mm wrench), brackets, and rubber fender liners entirely, and wipe the fender areas clean with a rag

2. Hold the M-Max Fender Flare in place on the body—a buddy can usually be coaxed to help by offering pizza. If not, a few strips of masking tape should do the trick. …on the Jeep, not the buddy.

3. With the flare in place, use a right-angle pick or a permanent marker to mark on the body where the bolts will go. Again, the Jeep’s body, not your buddy’s body. Lay the flare to the side.On the driver’s side, you may have noticed the bolt placement and bolt length on the M-Max Fender Flare is a little different. This is because the washer fluid box is just inside the engine compartment. We recommend you remove the washer fluid box before you start drilling through the body, although it’s not necessary. If you leave the box there, just be careful not to drill too far, and put a hole in the box. Otherwise you’ll be yelling at your buddy to get a towel.

4. Drill 3/8” holes at each of the marks you made for the bolts. We recommend using a step-up drill bit. If you don’t have one, drill small pilot holes first.

5. Place the M-Max Fender Flare on the body again, inserting the bolts into the holes to check the fit. If a bolt or two don’t match up perfectly and the flare won’t go on, don’t worry. Just drill that hole a little wider, until all the bolts fit at once.

6. Where the fender flare lays over any plastic trim on the body, use a pencil or marker to mark where the edge of the flare will go.

7. Use a box cutter to cut away the plastic, so the flare can sit flush against the body. The flares should now fit completely on, and the flare will stay in place by itself. But maybe don’t let your buddy go home just yet. If nothing else, he can always grab you another piece of pizza. Repeat on all flares

8. With the front fender flare on, use your right-angle pick or permanent marker to mark where the underside of the flare reaches on the body. Take the flare off again.

9. Mark a second line, 1” underneath the one you just made. This bottom line will be where you cut the body.

10. Put on your safety glasses, and tell your buddy to step back. Use your angle grinder or reciprocating saw to cut away the body, following the bottom line (1” below the underside of the flare).

11. At the top of the wheel well is a long metal tab that used to hold the rubber fender liner on. Cut that tab off.

12. Keep those safety glasses on. Now cut a slit about every 1” to 2” along the edge, to create tabs that will later be bent up. These slits should extend up past your original upper line, by about ¼”. The slits may need to be closer together at the corners, so that they’re easier to bend up.

13. Use your pliers to bend each metal tab you just created, up and out at a 90°. The bend should be at the top of the slits, above the original upper line. This way, the tabs will sit just inside the fender flare. Is your buddy getting jealous of your flares yet?

14. To make the tabs bend at a clean 90° angle, place your wood or metal block on top of each tab, and use your hammer to pound the metal from the bottom.

15. Set the front M-Max fender flares in place, and fit them as close to the body as they’ll go. Make sure the tabs fit just inside the flare.

Exact Shaping (optional)

At this point, you might see areas where the fit is not exact, and you’d like to improve it. You may need to sand away some of the flare, or build it up using a body filler, such as Bondo©, but we recommend doing this later, after all M-Max Fender Flare pieces are fitted to the Jeep. It will be easier to do all the Bondo at once. More details on this later.

Just How Tough?

Rear Fender Flares

16. Hold the rear M-Max flare in place, and repeat the process of marking where the bolts will go, drilling 3/8” holes, and making sure the flare will fit properly. Déjà vu, right?

17. With the rear fender flare on, use your permanent marker to mark where the underside of the flare reaches on the body. Take the flares off again.

18.Mark another line, ¼” above the lines you just marked. At this point it may help to explain what the plan is. Unlike the front fender, the rear fender consists of two pieces of metal—an inner fender and an outer fender—that are pinch welded together by the factory. You’re going to separate the two pieces, and will need to re-attach them later on, for stability. That’s why we warned you, there’s going to be some welding. The method we outline here makes the most of the existing metal, so you don’t have to add sheet metal. You’re going to cut away some of the outer fender, then cut and bend the inner fender up to meet the new edge of the outer fender. Make sense? OK, just keep following the instructions.

19. Cut the outer fender along the upper line you marked. Make sure you only cut through the outer fender wall.

20. On the lower portion of the fender that is now detached, the pinch welds are still holding part of the outer fender to the inner fender. There is also adhesive between the pinch welds. Cut vertical slits up into the metal, through the center of each pinch weld. Do NOT slit past your horizontal cut.

21. Now the sections of outer fender are only being held on by adhesive. Use a pair of pliers to pull those pieces off, leaving only the inner fender below the cut.


Trust us on this one… before welding, we recommend removing your battery terminals, as well as the bench portion of your back seat.

22. se a hammer to bend and shape the inner fender, giving your tire more clearance. Make sure the edge of the inner fender meets the new edge of the outer fender, so that you can weld the two together.

23.Buff the paint off the new edge of the outer fender, to get a good weld.

24. DO NOT weld the entire edge of the inner fender to the outer fender—this will distort the body. Instead, weld two tacks on each “tab” of the inner fender, to attach it to the outer fender.

25. Cut off any extra metal from the tabs, after they’re welded, and use a grinding wheel to clean up any rough edges or parts of the metal “tabs” sticking out too far. Make sure not to grind through your weld.

Exact Shaping (optional)

OK, now is the time to sand or Bondo the flares, if you want to get the most exact fit.

26.Use a sanding block or electric sander to gradually sand away the fiberglass on the flare, where needed.

27.If you want to fill in a gap between the flare and the body, remove the W-Max Fender Flare, and use masking tape to cover the body behind the part of the flare where you’re working. Make sure the tape follows the shape of the body exactly.

28. Replace the flare, and have your buddy hold it in place (or use a couple of the nuts) while you fill in the gap with body filler. Hold in place until the filler is rigid, and the pull the flare away from the tape. The body filler should stick to the fiberglass on the flare, but pull away from the masking tape without much difficulty.

29. Sand any uneven spots on the body filler with a sanding block. Once the shaping is done, we recommend you leave the flares off until they’re painted, but whenever it is you bolt them on, DO NOT over-tighten the nuts!

Sealing, Painting, and Mounting

30.Use a waterproof caulking or metal filler (like USC all-metal©) to fill in any slits or gaps in the wheel wells. Allow to cure.

31. Tape off and cover your vehicle, tires, shocks, springs, etc., leaving the edge of the fender exposed, but do not expose past the bolt holes for your M-Max Fender Flares.

32. Use a spray can of rubberized undercoating, and apply a layer on the edge of the fender, and the inside of the wheel well, to protect the metal from corrosion.

33. Before painting your M-Max Fender Flares, sand the entire outside with 220-grit sandpaper, until the whole surface is a lighter, dull gray.

34. Paint or cover your M-Max Fender Flares as you wish. Your buddy might have a crazy idea, but here at Notch Customs, we think matching it to your vehicle looks the best.

35. Mount your fender flares, using the rubber washers and nylon lock nuts included with your M-Max Fender Flares (11mm wrench). Again, DO NOT over-tighten the nuts! As you tighten the nuts, try to spin the washer with your fingers. Once the washer is snug, and you cannot spin it by hand, the nylon locking nuts will hold securely. Over-tightening may warp your body, or break the bolt loose from the flare.

36. Replace your door panels and trunk panels.

Now your Jeep should look about this awesome:

Sweet! Now send us YOUR photos!

Tell your buddy to get some pictures of you with your new M-Max Fender Flares, and send them to us We want to see your build, and you may end up featured on our website!

Any comments or suggestions?

We'd love to keep improving our products and instruction for future customers. Send us a message and let us know.