What You’ll need:
Any given suspension needs up and down travel to function properly. This allows your tires to move up and out of the way when they hit a bump, or drop down into dips and potholes. A stock 3rd generation 4runner has approximately 8” of wheel travel from max extension/droop to full bottom out on the bumpstops. When at static ride height, let’s say it sits right in the middle of its 8” of suspension travel, giving it 4” of up travel and 4” of down travel as shown below. The wheel positions at max compression and extension are shown in grey and the wheel position at static ride height is shown in black.
This travel range give the tires a comfortable suspension range to follow both bumps and dips in the terrain. Then, a 3” suspension lift is installed, moving the static ride height position 3” downwards in its 8” of total suspension range, as shown below:
Starting the Clearance Process
With those pieces removed, it’s time to remove the windshield washer system from the front of the passenger side wheel well. The washer reservoir must be replaced with a smaller unit and moved up into the engine bay. I don’t cover this relocation in this article, but there are other resources out there as well as complete relocation kits that can be purchased. Below is a picture of the wheel well space created by relocating the washer reservoir.
It is also necessary to relocate the vacuum system canister located at the front of the driver side wheel well. Luckily, I found that it could be simply moved further into the corner of the wheel well without any tire interference or the need to extend the vacuum line. I simply unbolted the bracket, bent the bracket arms slightly, and push the canister as far into the top corner of this space as possible. I then reinstalled the canister using an existing hole in the wheel well and an additional nut and bolt. Easy!
Once you have a good idea, remove the tire and start cutting! I used a combination of a 5” angle grinder with cutting wheels and a smaller pneumatic grinder with a 3” cutting wheel on it. Every so often, reinstall the tire, jack it up and turn the steering lock to lock again to reassess where more material needs to be removed. While cutting, be extra careful that none of the electrical wires or components have shifted and have fallen back down into harm’s way. I can assure you that I will not be writing a how-to article on how to re-wire your 4runner so you’re on your own for that one. Below is the final amount of cutting required for the driver’s side:
Creating the Firewall Tub
Before tacking your piece of sheet metal in place, double check that your damp towel is still in place behind your firewall to catch any sparks or excessive heat from damaging your interior. Now, take your sheet metal patch and lay it over the opening. To achieve a nice contour that maximizes tire clearance, I started by tacking the top edge to the firewall and then hammering the sheet metal into the opening. I then repeated this process of tacking and then hammering until the whole piece of sheet was contoured and tacked to the firewall. If you are using multiple pieces of sheet metal, repeat this process until the whole opening is filled. The driver’s side looked like this:
Then, finish off all sheet metal edges with weld beads. Take your time and use many short passes with the welder. Depending on your welder and amount of sheet metal welding experience, you may only be able to weld for a couple seconds at a time before burning through the firewall. So be patient and take your time. Once fully welded, move to the other wheel well and repeat this process. After tubbing, my passenger side looked like this:
I followed this up with a few coats of primer and then a rubberized undercoating that will absorb road debris spray rather than chipping off. Below are some views of the finished driver side tub:
And the passenger side:
Trimming your Outer Fenders
How did I measure out a clean cut? I simply plotted points all around the fender opening by measuring 1.25” from the fender edge and marking the point with a permanent marker. I marked a point every couple inches around the fender and then connected the points with a straight edge, as shown above.
Here are some photos of the finished fender and firewall profiles with the tires reinstalled. As you can see, my cut line smoothly follows the factory fender line until the bottom corner, where it tapers to a slightly more substantial cut. The drivers side:
And the passenger side:
And the whole truck, sitting nice and low on those 35’s.
I hope this article was informative to you and will give you the confidence to tackle this modification on your own vehicle. While it is a very time-consuming project that has many irreversible aspects to it, I am confident that anyone with a small amount of mechanical inclination is capable of doing it. Just plan everything out in advance and take your time. I promise you that the end result of 35’s and a low ride height is worth it!