Trim Those Mounts!
Body mount trimming from my post on FJ Cruiser Forums:
Everyone knows the FJ comes from Toyota with oversized body mounts in the front wheelwell that severely affect the installation of larger tires. The FJ owner only has 3 choices, dont put on bigger tires, install one of the new & way too tall 6" lifts, or cut the mounts to enable larger tires with smaller lifts, keeping the vehicle lower & more stable. A search on this site will produce many photos and descriptions of how body mounts have been done, this is just a post of how I do them.
I have done several sets of body mounts for myself and board members, but yesterday while doing them for Jeshua to clear his 285's with no lift, I had a thought of how to get a bit more clearance than the way I was doing them previously. After finishing them, and considering how tight they wrap the factory bushing, I dont know that you could get any more clearance for bigger tires than this. This setup has less than 1/4" gap between the bushing and mount face. In addition, I use 3/16" thick x 2" wide steel to reinforce the mount - I know you can get away with 1/8" but for the difference in cost why skimp. It is a harder job to work & bend the 3/16" around the radius of the bushing, but not having to ever worry about it failing is worth the extra effort.
When he pulled into the driveway, it was evident the tires were rubbing the mounts and here's what I saw
And when the wheel was turned it was easy to see the contact
Fter pulling the tire it was easier to see where the tire was contacting the mount. Surgery will be necessary.
Here's a shot from below of how huge the body mount is from the factory, you can see how much area the tire was rubbing along the bottom of the mount
and from the top... these are obvoiusly the "before" shots
Now we cut... I always wonder whats going through the head of the person watching me cut on their truck. I look at where the most forward edge of the bushing is and mark the mount about 1/4" in closer to the frame (this is more than you would need to fit a 33x12.5 or "305" tire, but this allows adding a 35" tire later if desired.) Then remove the bushing and cut up, over & down the back, following the radius of the bushing cup. DONT CUT INTO THE BUSHING CUP, CUT AROUND IT! The bushing cup is the dipped part that the top bushing sits in. If you run a 35" tire (I do) then the bottom lip of the mount will rub the tire, so I trim the bottom lip further and knock off the edge with a 45" slice, and round all corners with the grinder. This is the reason I use thicker material than needed. The red line is where I will put a 2" slice in to bend the face in a bit farther - this is the different step I thought about mid job & Jeshua volunteered his truck as guinea pig.
Here's the cut mount with edges ground & cleaned and slice in the top radius
After installing the bushing over the stud, I hammered the flat face under the slice to about 1/4" from the bushing and ground the area to be welded. Make sure and get plenty of penetration, you dont want cracks!
From this point, you can do 2 things, make a cardboard or paper template of the plate to cover the cut, or what I do is weld the plate to the face of the mount on the vertical section, and about 1/2" along the top. Then hammer and stitch it around the radius of the mount until it meets the back of the mount, and finish weld it along the back. I prefer the smooth factory look, so I add material where needed and smooth with a sanding disc - I like the new 3M purple 36 grit ones, they last about 5x longer than the old green discs. It will look like this
From the top you can see how close it follows the raduis of the body bushing
From the bottom, you can see the upper bushing cup. The crucial clearance areas for the tire are the front to end (9 to 12 o'clock position). Once it wraps past the edge of the bushing farthest from the frame the clearance is inconsequential because if it would hit there, it would be hiting on your firewall too and thats another tech article
Making sure the bushing clears the new mount face
Heres the finished mount with the bushing installed. If there's a way to get more clearance I'd love to see it. After doing the mounts this way I plan on redoing mine with the slice cut and getting the 1/4" extra clearance, as that will eliminate the slight remaining rub I experience on my FJ with the 35" tires and 17x8.5 rims with 3.75" backspacing
And here's Jeshua's finish painted mount with the 285's installed back on, and no lift
and with the wheel turned - this is the closest the tire will ever get to the mount
With the extra step of the slice cut the total job took 4 hours. But now the FJ has plenty of clearance at the body mount to run bigger tires even with no lift. Its not that difficult and keeps those expensive tires form getting torn up every time they rub. There's nearly 1.5" of gap from the tire to the mount at the closest point now compared to the direct contact prior to the mod.
