DISCLAIMER: USE AT YOUR OWN RISK. ALL OF THIS IS FREE AND OPEN TO ANYONE AND IS PURELY MEANT TO SHOW CASE ONE WAY SOMETHING WAS DONE. NO ENGINEERING OR LEGAL ADVICE IS INTENDED.

I've built three different long travel setups for three different 4Runners, and always wanted to share the knowledge, but have always been afraid of the legal aspect... but lots of places sell DIY or weld it yourself suspension kits and seem fine, and I'm doing far less--providing pictures and CAD of what I've done--so hopefully everyone can play nice and not hurt themselves.

The first two setups (one for a 1st gen) were very basic with some square tubing and plates and not much more. I still have mine hanging on the wall in my shop, and it held up great and was built to be extremely simple and economic. That same setup could be repeated easily, but with how common plasma tables or cutting services are, this will focus on my most recent design:



Again, this is NOT meant to be used in any regard but just a form of advice and reference to anyone else! With that said this truck drives all over, just got beaten on at KOH, and me and my buddy literally measured, designed, and built the whole front suspension in two weekends. There are many aspects that are not perfect, but for people that don't want to buy a Total Chaos or Camburg kit and like to build stuff, this is a pretty simple and quick setup you can REFERENCE.

Specs:
.120 plate
Boxed LCA with 1" uniball and bushings
Boxed UCA with 1" uniball and 0.75" heims
8" coilover with stock coil bucket
Completely stock 1st gen Tundra CVs
Cycles ~14"
Pushes Hub Forward 1"

Files (Requires CAD, such as Fusion 360 (free to Hobbyists)):

3rd Gen 4Runner (and presumably 1st gen Tacoma):

Frame Scan: Free CAD Designs, Files & 3D Models | The GrabCAD Community Library
2D Stock Dimensions: 2D Layout.SLDPRT - Google Drive
3rd gen 2D LT Dimensions: 2D Layout Extended 3.5.SLDPRT - Google Drive
LCA (plate construction) STEP: Free CAD Designs, Files & 3D Models | The GrabCAD Community Library
LCA (tube construction): Free CAD Designs, Files & 3D Models | The GrabCAD Community Library
UCA (Plate Construction) STEP: https://grabcad.com/library/3rd-gen-...g-travel-uca-1
UCA (tube construction, much older model) STEP: https://grabcad.com/library/3rd-gen-...l-uca-simple-1

LCA Plate SolidWorks: https://drive.google.com/file/d/1Flk...ew?usp=sharing
UCA Plate SolidWorks: https://drive.google.com/file/d/1uDR...ew?usp=sharing
Front Suspension Frame Scan: Free CAD Designs, Files & 3D Models | The GrabCAD Community Library

1st Gen 4Runner:

LCA (tube construction) STEP: https://grabcad.com/library/1st-gen-4runner-3-25-lca-1
UCA (tube construction) STEP: https://grabcad.com/library/1st-gen-4runner-3-25-uca-1



Files Explained:

The 2D layouts are pretty confusing. They are 3D sketches with lines and points marking locations of everything and to some extent are movable once certain constraints are removed. They were mainly to give a quick way to visualize the geometry through the suspension cycle. As you can see in the top there is an angled line--that is the axis of rotation of the UCA for example. Likewise there are measurement for the LCA bushing location, the LCA geometry, the UCA geometry, the spindle, CV cycling, etc. There is a file for the stock geometry, and one for the +3.5" arms.



The step files are explanatory, they are a single step of each arms entire assembly.

The pack n go are all the solidworks files and assemblies. Fusion360 among others can open native solidworks files if you don't have access to solidworks.

The frame scan I got after designing this long travel setup, but I've included it for anyone wanting a frame scan. It has some additional axis and planes I added to represent geometry positions like the steering rack being extended or retracted, cam tab position, etc. The frame scan is a bit of a ***** to work with but as accurate as you'll get (it's also a large file). There's some more information in following posts below, use it as you see fit.

Suspension

UCA:

2024 Edit: The RevB mentions are for reference, all the models posted are for RevA which should still cycle fine. I would suggest tack welding the RevA arms and cycling them and then adjust the angle of the uniball as needed, that's what we originally did. The RevB model is broken so I didn't upload the files, so keep that in mind with the next few sentences. The angle difference from the old models I can find appear to be ~4.4deg flatter for the uniball plates relative to the axis of the heim bung (19.4deg on RevB vs 23.8deg on RevA):

The first note is there is a RevA and RevB of the UCA. The initial UCA we built didn't have the correct angle in the uniball as I recall so the uniball was bottoming out too soon. This was iterated on for RevB as you can see the angle change between the two and the other dimensions remain constant. I'm not sure why the side plates of the RevB arm are missing, but the upper plates appear mostly correct for the updated angle. At 14" of travel a uniball with the bolt going vertical and at 3.5" wide means the uniball maxes out in both directions so it's not physically possible to cycle more than that--thus why correcting the alignment from RevA was so critical.

This is the UCA RevA:


The uniball cup is equally spaced off both faces so a weld bead can be laid around it. Personally I have the shear lip (the side opposite the c-clip) to be on the bottom, so in the event the LCA fails and there is high loads trying to pull the spindle out of the UCA then there is the strongest portion of the uniball trying to react it.

The alignment features for the UCA didn't work great and were a ***** to weld over with MIG (as can be seen from the blobby welds in lots of pictures). The alignment features weren't a crisp cut on my plasma table, so I had to go in with a cut off wheel and square up a corners on most of them too.

The bungs for the heims are not the most elegant solution, I would prefer a square billet that is tapped but this is what we had to work with. There is a plate with a hole that the bung slides into and is welded to. The point of the heims is to allow for alignment adjustment in the event the LCA stock cam tabs run out of stroke. This has proven to be very effective.

The point of using a boxed upper was the alternative (bending tube) would be harder to get the alignment right. This did not require a jig and was still relatively precise. On my original LT I did on my personal truck, I used multiple pieces of square tubing that had angled cuts to create the UCA. That is a bit more elegant, however a beauty of this is that the UCA can have a very complex geometry to it to maximize the uniballs angle.




LCA:

This is the LCA without shock mounts:



The LCA shock mounts were not added until both arms were fully built. At that point the shock and arms were installed, and the suspension and shock position mocked up and cycled. I am not sure of the actual shock size needed or how much travel was ended up being used, but you can see in the following pictures roughly where the shock was to clear the CV and pull the travel needed.



The CV is a stock Tundra CV off of a 1st gen. I brought the inner tripod CV up to the very edge--we've never had one slide out, but this is required because at full plunge there is very limited angle to work with. The more the CV is pulled out of the tripod the more angle is allowable. Having both the UCA and the LCA have adjustment also allows the CV plunge to be dialed in in the event that the inner tripod gets over extended and falls out.

Again, the alignment tabs worked but needed to be squared off for better fitment. There is some internal gusseting to the arm, but overall it is pretty simple. I welded up the interior, welded the top plate on, welded as much as I could, then welded the outer sections to box in the arm. The bushings are centered to get a weld bead on both edges, and the uniball is roughly centered too. I also added some little overlay plates at the angle junction between the bushing legs and the main triangular interior of the plate after everything was done to make sure the legs wouldn't pull off. Though as you can see the legs extend well into the triangular plate, so there is never a single plane of only weld.






Spindle:

What I originally did on my truck, and the exact parts carried over to this one actually: is take a stock LBJ, grind the circular indent on the top and then the ball joint itself will be able to pop out through the top. I then welded a slug into the hole where the LBJ goes, and then ran a normal bolt down through that slug (making sure the bolt head stays flush or below the top of the casting). This makes the bolt a standard off the shelf item that just runs through a standard LBJ part. Additionally I then welded a double shear plate for the heim for the steering, and drilled out the steering arm to whatever the bolt size was. This setup is extremely strong, and maintains essentially stock geometry. One thing I found is you MUST use a cotter pin on the LBJ bolt, I repeatedly had the nut come loose regardless how I tried to stake it and the cotter pin was always the saving grace (even ended up shearing through one once). Checking that bolt is #1 of the daily LT walk around check imo. Ideally the nut wont move, but be prepared if it does.

For the steering, bump steer is a big issue. This is actually very simple to correct: by spacing the tie rod/heim down, bump steer is reduced--until a point in which it comes back. In the stock position, the tires will toe in as the suspension droops which turns into a circle effect: accelerate, droop, toe in, suspension tries to come together and droop more, etc. Because of this I prefer to have the suspension cycle with a SLIGHT toe out motion as the suspension droops, then there is no chance for it to go crazy. You want your toe to be straight at ride height, but be slightly in at full droop. To do this, just use washers between the LBJ steering arm and the heim for the steering and cycle the suspension until it's at where you want. Ideally turn that washer stack into a spacer. This is the reason the double shear arm in the photo below is so much lower than the stock steering arm: the heim was sitting against the lower plate, with a large spacer above it to dial in the bump steer. This took me a VERY long time to figure out initially, and then we built this setup and within 30 minutes had the truck bump steer set where we wanted and then it drove 200 miles on the interstate. The double shear plate is CRITICAL. While a bolt in single shear will work (I drove a lot like that), I've also had the bolt snap running into things. The double shear plate fixed that instantly.

No bump steer is obviously best, but due to the spacing of the uniballs and the stock geometry being used, there is no EASY way around it besides the washer stack imo. I am laying out a new LT setup that uses a fully fabricated spindle to set everything where I want it, but at the end of the day it's the same effect: putting the steering in the right spot relative to the arms.

NOTE! with the design I have, at full droop there are steering positions where the LBJ bolts can run into the LCA. There are also no steering stops. This is probably the biggest issue with how I did it. If the arm was kinked differently or had a two part kink so the end kicked up to clear the LBJ setup that would work. Just remember that the LCA uniball angle is important since it is a driver for suspension travel since it can max out. A different spindle to uniball adapter would be another solution. This was only a problem at full droop.




Tie rod
Tricky at higher travel, we built an adapter for a heim for the rack initially but that got swapped out for a Camburg heim adapter which has been great. The tie rod is just a piece of tube with heim bungs. The tie rod needs a little trickery to get the angles all happy since you want the heims to match the uniball angle essentially. Having a horizontal bolt for the heim would fix that (like how the rack side is oriented) but is much trickier to add plus then you have no bump steer adjustment so make sure it's correct.

UCA to spindle

My original setup was two machined pucks that would clamp the spindle bore (think a revolved C shape then slice in half) and worked awesome. As long as the uniball bolt was tight then the adapter was in place. My buddy went with an aftermarket adapter like for any normal UCA. Like I say in point #3, that ended up ripping through the spindle but since the adapter he had was stainless I was able to just weld it back directly onto the spindle. If you have a lathe it's easy to make an adapter, if you can buy an adapter that's great too, but I would recommend at least gusseting that thin section around the UBJ adapter since I've seen that as the primary failure mode once everything else gets beefed up.



That will wrap it up for now. This suspension I made ~2 years ago. Always felt like someone could benefit from the work we did. Maybe these files and notes will help someone trying to build a cool truck too.

Thanks a lot for posting this up man! I have a couple questions:

1. The uniball slug pressed into the LBJ, did you machine it to taper off at the end like the LBJ housing does? Or is it just a 1.5" diameter slug?

2. Is the kit pretty much stock geo, extended 3.5, with the upper and lower pivot points pushed forward 1 inch?

3. Any failures or weird tire wear?

1. No taper, I just did a round puck, and where that lower hemisphere is I laid a bead of weld in and then another bead on top of the puck. I also cut a hex out of the top so the bolt head was locked in from rotating, though I can't remember for the life of me how I did that (made the LBJ adapter around 2014, and then it got moved to this second setup and still being used).

2. Yes more or less. On my original setup it was literally that, on this one I took the 2D stock dimensions and then extended the CV the 3.5" so the CV drove the arm length. I would say this is important because the arms don't grow a true 3.5" since they're angled differently than the CV is--with that said my original setup I never had any issues with the CVs, presumably because the length difference of just extending the arms 3.5" vs the CV length being the controller is a very small difference in reality.

3. Never had a failure of any arms. I've had the steering bolt shear when it was single shear and I was on ice off-road and hit a tree with the tire. Had the nut loosen for the lower uniball bolt but never come off fully, and then I added the cotter pins after that. Had the stock bolts that hold the LBJ piece on fail multiple times--the 4runner shown actually ended up welding the LBJ adapter to the spindle after his bolts failed too. And lastly the most impressive, at KOH this year the 4runner shown was bombing through whoops and was too softly valved and hit so hard that the LCA bottomed out and there was such a huge bending moment on the spindle/arm that the thin section of the spindle that goes into the uniball adapter ripped out--we were able to drive back to camp with the spindle just cantilevered off of the LCA uniball. The LCA and UCA got absolutely beaten and no signs of anything wrong, though I didn't get to thorough inspect it. After that I welded the uniball adapter for the UCA directly to the spindle and gusseted it on. Oh also, the 4runner shown ran into a huge washed out hole on a road, and the tie rod yielded but everything else was fine. So in regards to the arms, they seem fine. This was all out of mild steel plate too.

I think I have some FEA laying around, but not sure. Figuring out a realistic quasi static load is hard from my research (though I had someone recommend 10G frontal, 5G vertical, 2G lateral and is what I based my original design off of). This version I mostly winged by intuition and knowing it should be similar strength to the simple tube/single plate setup I did my first go around. Additionally if you compare this to a total chaos or addicted, they're literally two tubes in some cases and i would be surprised if they're more than .125" wall, where as this is a fully boxed beam of .125" plate. With that said, this is for REFERENCE, just what has worked for me and the wheeling me and my friend have done.

Forgot to answer the tire wear: it's hard to say, the 4Runner shown is the only one that has had a proper alignment done and it seems to drive and handle fine and maintain proper camber and toe, though it's not a daily driver either and I don't know how many miles have been on it. My 4Runner was eyeball aligned, and one set of tires had some bad camber wear even though at static ride height it seemed to be at 0deg, and the second set of tires wore fine but didn't get a lot of miles, so take all that as you will.



Also things to add that I'll put in the OP:

Tie rod
Tricky at higher travel, we built an adapter for a heim for the rack initially but that got swapped out for a Camburg heim adapter which has been great. The tie rod is just a piece of tube with heim bungs. The tie rod needs a little trickery to get the angles all happy since you want the heims to match the uniball angle essentially. Having a horizontal bolt for the heim would fix that (like how the rack side is oriented) but is much trickier to add plus then you have no bump steer adjustment so make sure it's correct.

UCA to spindle

My original setup was two machined pucks that would clamp the spindle bore (think a revolved C shape then slice in half) and worked awesome. As long as the uniball bolt was tight then the adapter was in place. My buddy went with an aftermarket adapter like for any normal UCA. Like I say in point #3, that ended up ripping through the spindle but since the adapter he had was stainless I was able to just weld it back directly onto the spindle. If you have a lathe it's easy to make an adapter, if you can buy an adapter that's great too, but I would recommend at least gusseting that thin section around the UBJ adapter since I've seen that as the primary failure mode once everything else gets beefed up.

Very cool, that all makes sense. I see camburg sells the upper uniball adapter for $50, so thats a no brainer to me.

Also I opened the files and see that there is only one side modeled, is it just a simple case of cutting out X2 of the plate and flipping it over for the opposing side? Files all opened correctly for me fyi

Thanks for the notes, I've been designing a system for my 4th gen for the past 6 months. I've learned a lot so far and haven't even begun building it yet. Starts on page 78 of my build thread for those interested in reading.

Correct, same plates just flip them.

Very cool and props for taking the time to document it and share.

~Jason

That is very cool! Much fancier than anything I've ever done. My "next generation" setup is along a similar approach, though I'm pretty lazy about working on it since I don't have a 3rd gen anymore.

Some more information, some of which I'll add to the OP:

This is the original long travel I did for more reference. As you can see the UCA is just some sections of square tubing (4 in total as I recall) with miter cuts that wraps around. Very simple, though harder to get good uniball misalignment since I just took a hole saw perpendicular to the arm. You can also see the LCA setup, again square tubing skeleton and then I just had a single plate welded to the bottom. The arm was completely flat, no kink, which required cutting out the bump stop area of the frame to utilize more up travel where as a kinked arm can get around the frame. You can also see I cut out the stock shock towers, which was a mistake but I was trying to stuff a 10" shock for no real reason (I was like a sophomore in college with no money or tools, thus why everything is square tubing). I wouldn't recommend doing a lot of this, but just other options of ways to do things. Never had any issues with these arms, they're now hanging on my wall. Spindle has always been the weakness of the 4Runner.



My friend scanned a section of frame and sent me the model. Not sure I should put it out there, but better to ask forgiveness than permission. I'll add the link to the OP as well. There are a lot of planes and axis that I added to represent certain geometry points like tie rod extended/retracted, cam adjusted out/in, etc. For my "next generation" that I posted pictures of above, I still use a 3D sketch to quickly mock up geometry and cycle it and then go in and make mock up 3D parts to match the sketch, then flush those "guide parts" into actual structure. This file is just the frame piece (driver side) and is fairly large; since it's a single part I just put it on GrabCAD.

Free CAD Designs, Files & 3D Models | The GrabCAD Community Library

Super cool thread. Thanks a lot for sharing and posting this. I need to read and start digging way deeper into this. I'm sure many questions will follow!

I'd love to see a +2" option for the 3rd gen.

Was there any modification needed to run the 3/4 helms on the upper arm? Im assuming the stock long UCA bolt is not a 5/8s that will fit into the misalignments?

I forget what the misalignment bore is, but it's one of those imperial sizes that is nearly identical to the metric equivalent, so the off the shelf misalignment does actually work with the bolt completely fine and is a pretty close fit. With that said I don't know if the CAD misalignment is correct, I'd assume so but you should double check. I guess the frame scan probably shows an accurate bore too. With how easy it is to get some calipers onto the UCA frame bolt I'd do that. I'd like to say the misalignment is a 9/16" bore...

Same thing goes for the bushings. They are straight off the shelf and the width and sleeve bore are a perfect fit for the chassis/cam bolts despite the bushings being imperial units.

TONY'S BACK


Maybe I'll have to try this one day


Thanks for the files!!

Any chance on having plans that would utilize a press brake rather than welding every piece together?

Mike

No sir, I only design things with tools I have

Should be pretty easy to take multiple parts and combine them into one with bends though.