Installing Subaru mud flaps requires removing selected wheel-well fasteners, positioning the flap level with the ground, and tightening the supplied hardware only after final alignment is confirmed.
What You Need Before You Start
Park on a level surface and turn the steering wheel fully toward the side you are working on. Some Subaru models and brands require raising the car and removing the wheel for adequate access to the mounting points. Have a flathead screwdriver, a 9/32 drill bit (if drilling is needed), and the supplied mud-flap kit hardware ready. Check whether your Subaru has factory splash guards or arch protectors before you start.
The Standard Installation Sequence
The install pattern is similar across most Subaru WRX, Outback Wilderness, Crosstrek, BRZ, and Legacy models, though fastener counts and bracket layouts vary by kit.
- Remove the factory fender-liner fasteners. A typical front install uses 2 to 4 plastic fasteners; on 2024+ Crosstrek models, the front uses two plastic fasteners plus one drilled hole.
- If your Subaru has splash guards or arch protectors, remove them. They may be held on with strong adhesive in addition to fasteners.
- Install any supplied clips, spacers, or brackets before mounting the flap.
- Fit the flap loosely so it can be adjusted. The logo side should face the rear on most Rally Armor installs.
- Align the flap so it is parallel to the ground or level with the vehicle body.
- Hand-tighten the hardware only until the washers seat. Tightening too early prevents alignment, and overtightening can deform the flap.
- Reinstall the factory fasteners you removed, or use the supplied replacements.
Model-Specific Variations
Every Subaru mud-flap kit ships with slightly different hardware, so checking your instructions matters more than a universal guide. A few examples from verified manufacturer sources make the differences clear.
| Subaru Model | Kit ID / Brand | Key Differences from General Pattern |
|---|---|---|
| 2022 Subaru WRX | AMS Performance | Remove all 4 wheels; remove 4 fasteners; use 3 supplied screws and a spacer at bottom inner point. |
| 2022+ Outback Wilderness | Rally Armor IMF76 | Turn wheel for access (no wheel removal); install polygon clip and 0.25-inch spacer; hand-tighten only. |
| Legacy / Outback | Rally Armor IMF34/36 | Uses 2 poly edge clips, a flat U clip, an insert for the liner point, and a spacer behind the lower inner mount. |
| 2024+ Crosstrek | Generic / aftermarket notes | Front uses 2 plastic fasteners plus a 9/32-inch drilled hole; rear uses stainless bracket and one drilled hole. |
| 2015–2021 WRX/STI | Various aftermarket | Leveling the flap before final tightening is the most repeated step; wheel removal helps with inner access. |
| 2022+ BRZ | Aftermarket install video workflow | Wheel-off install; same fastener-removal sequence as the AMS WRX instructions. |
Common Mistakes That Cause A Poor Install
The most frequent source of crooked or loose flaps is neglecting alignment before final tightening. Multiple manufacturer sources emphasize fitting the flap loosely, leveling it, and then snugging hardware only after alignment looks correct. Skimping on the spacer at the inner or lower mounting point is another reason flaps sag or vibrate at highway speed. If wheel-well access is tight, removing the wheel is far safer than working around it with the car on a jack. Before heading out, check that all factory liner fasteners are back in place and that no hardware is contacting the tire at full steering lock.
Looking for the right set for your Subaru? Our tested mud flap recommendations for the WRX compare fit, coverage, and hardware quality for this exact model.
FAQs
Do I need to remove the wheels for installation?
It depends on the model and kit. The AMS Performance WRX instructions and BRZ install guides require wheel removal. The Rally Armor Outback Wilderness instructions turn the steering wheel for access instead, leaving the wheels on. If you cannot reach the inner fasteners comfortably, remove the wheel.
Will this installation require drilling into the car?
Some kits require one or two drilled holes, typically in the plastic fender liner rather than the body. Kits for the WRX and Outback Wilderness typically reuse existing factory holes without drilling.
What happens if I overtighten the mud flap hardware?
Overtightening can strip the plastic insert or deform the flap near the mounting point. Rally Armor explicitly instructs hand-tightening only until the washer seats. Tightening too early also locks the flap in a crooked position before you have a chance to align it level with the ground.
References & Sources
- AMS Performance. “2022 Subaru WRX Mud Flaps Install Instructions.” Documents wheel removal, 4 fasteners, spacer use, and oversized mounting holes for adjustment.
- Rally Armor. “IMF76 Installation Instructions – 2022+ Subaru Outback Wilderness.” Includes polygon clip, 0.25-inch spacer, and hand-tightening guidance.
- Rally Armor. “IMF34/36 Installation Instructions – Subaru Legacy Outback.” Specifies clip types, insert, and alignment before final torque.