ARB Radiator Support Bracket For 5th Gen 4Runner – Install & Review

Shortly after adding a Toytec Boss Aluma Series lift on my 2018 4Runner TRD ORP, I noticed a popping sound coming from under the front area when out on the trails. Oddly, this wasn’t a sound that I had noticed while daily driving.

Even on the first couple of off-road trips, it didn’t happen very often. Perhaps those heavy jams while rolling through various obstacles drowned it out. After the new suspension components had a chance to settle in a bit, the mysterious and annoying popping (or sometimes tapping) noise became more noticeable.

At that time, my OCD fully took over and I was on a mission to find out the what, why, and how to solve this noise issue. Troubleshooting became a constant effort. I greased, wiggled, pushed, and pulled on every front-end component trying to narrow it down without much success.

During all the endless hunting, I noticed how close the sway bar was to the driver-side stiffener brace (some refer to these as the radiator support brackets).

The Problem

As you can see in the photo above, there was not much clearance at all. There was literally between a 1/8 and a 1/4 of an inch of space. That’s while the rig was parked on level ground in my driveway. After a quick dive down the Google rabbit hole, I stumbled on other 5th Gen 4Runner owners who have had the same issue.

Solutions ranged from removing the sway bar to upgrading the stock skid plate with an aftermarket skid. The latter option often involves deleting the stiffener brackets altogether. Some people even took a grinder to that stiffener bracket to notch a little more clearance for the sway bar.

After reading about those solutions, I was at a crossroads and unsure how to solve my issue. I wasn’t ready to drop the cashola on an aftermarket skid because my stock skid is still in pretty good condition. Removing the sway bar would give me more articulation on the trails, but it didn’t seem like the safest solution for a top-heavy daily driver. That would also make navigating around crazy city drivers a bit sketchier than some of the most off-camber sections on trails.

Honestly, I normally have no issue with cutting and grinding things on the 4Runner to get things dialed in. However, I didn’t like the idea of cutting out a section out of something intended for stiffening support.

After a bit more research, I stumbled upon a product that was a safe, budget-friendly solution without all the grinding. In comes the ARB OME BP-51 Fit kit for the 5th Gen 4Runner.

ARB OME BP-51 Fit Kit

The ARB OME BP-51 Fit kit includes several clamps and mounting components to fit and install the complete BP-51 lift kit on the 5th Gen 4Runner. The kit comes with a reservoir clamp, some reservoir brackets, sway bar relocation brackets, an adjuster tool, and an assortment of fasteners needed for the complete kit install.

The kit also includes a specific part that I needed to solve my noise issue: the driver’s side stiffener brace mount.

Pictured above: (Top) ARB OME BP-51 4Runner Stiffener Brace Mount | (Bottom) Stock Stiffener Brace Mount.

For this solution, most of the ARB kit is not needed. With my rig running a Toytec lift kit that included a diff drop and sway bar relocation brackets, I only needed the stiffener brace mount and (2) M10 caged nuts.

Installation

Tools & Materials Required:

• 3/8 Ratchet
• 3/8 Ratchet Extension
• 12mm Socket (x4 Skid plate bolts)
• 14mm Socket (x3 Stiffener bracket bolts)
• Impact Driver (Optional, but speeds things up a bit)

The new stiffener brace mount is shaped to be more “low profile.” It gives the sway bar more clearance, thus avoiding any potential contact. In short, it solves the issue of the annoying noise I heard.

The installation only requires the removal and reinstallation of (7) bolts. It took me 30 minutes to complete the installation, and most of that time was spent figuring out which caged nuts fit with the stock bolts for the stock skid plate.

Before You Get Started: Remove Factory Skid Plate

To access the driver-side stiffener mount, we need to remove the front factory skid plate. To remove the skid plate, remove four 12mm bolts. Set the skid plate aside along with the (4) bolts. We reinstall these in the end.

Step 1. Locate The Driver Side Brace Mount

With the front skid plate removed, you’ll see the (2) stiffener brace mounts. We only want to remove the one on the driver’s side.

Step 2. Remove Driver Side Brace Mount

Once the driver’s side brace mount has been located, remove the (3) 14mm bolts.

Set aside these bolts as they’ll be reused with any previously installed spacers.

Step 3. Gather Needed Components From The BP-51 Fit Kit

To prepare the new BP-51 stiffener brace mount, find the caged nuts in the hardware bag. Be sure to grab the ones that will fit the original bolt holes for the skid plate. The caged nuts will fit and slide into the two square holes seen above in the brace mount.

Step 4. Insert Caged Nuts Into BP-51 Brace Mount

These caged nuts have little flared-out feet on them. Insert them by sliding one side into the square hole and pushing the other down into the hole till it clicks in place.

The second one requires some fancy fingerwork, as you need to push it into the frame of the brace and get it to click in. The photo above shows the correct orientation. These caged nuts are what the stock skid plate will attach to on the driver’s side.

Step 5. Gather Brace Mount, Original Bolts & Spacers

Once the caged nuts are in place and you have gathered all the original spacers and the three 14mm bolts. you are ready to start assembling it all back together.

Step 6. Insert The Middle Bolt & Small Spacer

I like to start with the middle bolt by inserting it into the brace with a small spacer.

Note: This was a part of the sway bar relocation kit from Toytec, yours could be different.

Step 7. Install New Brace Mount

Line up the middle bolt and spacer to the mounting plate just to get the threads started. Don’t tighten it down just yet.

Step 8. Align The Front Bolt & Spacer

Get the front bolt and spacer lined up and threads started.

Step 9. Align The Rear Bolt & Spacer

Once you have all three bolts and spacers in place, tighten them all down.

Final Step: Reinstall Stock Skid Plate

After all (3) 14mm bolts on the new BP-51 brace mount are tight, you can reinstall the stock skid plate.

Be careful when inserting the (2) 12mm bolts on the driver’s side and do not push on the bolts too hard when trying to get the threads started. Pushing those caged nuts out of the square holes on the new brace mount will not take much force. I accidentally pushed them out and had to rework them back in, so just take your time.

It is best to install the passenger-side bolts first. Then, lightly install the driver-side bolts into those caged nuts. Finally, tighten them all down, and that will complete the installation.

Final Thoughts

As you can see in the photo above, the BP-51 brace mount gives much more clearance for the sway bar. The only issue I can see in the long term is those caged nuts for attaching the skid plate. I hope they won’t stick and maybe seize those square mounting holes over time.

I do all my own maintenance, so I can be mindful of being easy with them. However, if you take your 4Runner to a shop for service, maybe getting some nuts welded to the brace mount instead would be better in the long run. Overall, it’s a nice solution to an annoying sound issue.