Rocks & Flops: a 1-Ton SAS Build

[Team_Jake]

Time to cut all the old brackets off the housing.

After an eternity of measuring (and another eternity of CAD) I made a truss with integrated bump pads, link mounts, coilover mounts, limit straps mounts, and sway bar mounts. All metal was laser-cut and bent by SendCutSend. (Looking back on it all I really wish I had purchased a 3d scanner, it would have cut my measuring/CAD time down to ~1/4 of what it took without it).

Checking the clearances with the oil pan and upper-link / motor-mount.

 

[Team_Jake]

Drag-link and tie-rod brackets for the knuckles.

Mocking up the frame-side panhard bracket, and then welding it all together. The drag link and panhard bar use 7/8-14 heims (3-piece heims from Barnes 4WD), and the tie rod uses 7/8-14 offset heims (from Barnes 4WD), all will be using 3/4" grade 8 bolts for mounting.

 

[Team_Jake]

The link mounts on the frame will be integrated with a cross member and a transmission mount (factory mount replaced with a poly mount from 4xInnovations, part number TCC1326).

 

[hntz4x4]

Very nice!

How do you plan to do 4 link rear and keep smog legal (gas tank)?

Ryan

 

[96RedRunner]

View attachment 415935

80 series full floater?

 

[clearock]

80 series full floater?

Ruffstuff Tundra 10.5" housing, Tundra 10.5" 3rd, Reid Inner and outer Ford Dana 60 Kingpin C's and Knuckles, 2009+ Dodge 3500 14" rotors and calipers, RCV 300m custom Shafts.

 

[Team_Jake]

[MENTION=312703]hntz4x4[/MENTION]

F150 fuel tank swap (I’ll post more on that later)

 

[raKnizek]

Really impressive work. Excited to see where it
Goes!

 

[Team_Jake]

Next was bump stop mounts and coilover mounts. I bought the hoop towers from Barnes 4WD (part number B4WK12515), and used some 1/4" tabs for the upper mounts (found on Amazon, brand Lifetime LED, part number ORI-SHT15).

Then I installed all the links. The lower links are 2" OD x 0.25" wall DOM with Johnny Joints (part numbers CE-9114 and CE-9114L). The upper link is 1.5" OD x 0.25" wall with Johnny Joints (pieced together from part numbers CE-9116FN, CE-9116FN-L, CE-91122B, and CE9112NRK). Checking all the clearances, yeah it's tight!

 

[Team_Jake]

Installing the coilovers and drag link and checking all the clearances. The coilovers were ordered from Accutune, they are Fox 2.5" x 14" with remote reservoirs, with the 1" shorter lower eyelet option. Bump stops are Fox 2.0" x 2.0".

 

[Team_Jake]

Now to paint, brake lines, and then final assembly. I also installed new ball joints by Kryptonite (part number 9920BJPACK), new Timken units bearings (part number SP580205), and a new Motobilt diff cover (part number MB4043).

 

[Team_Jake]

I installed 5.38 gears from Revolution Gear and Axle (master install kit part number Rev-F250-538-K), and an Eaton E-Locker (part number 14022-010). Gear pattern checks out.

These 5VZ engines have a low hanging A/C tensioner pulley that really like to get in the way of the drag link when it is at full passenger lock + full passenger bump + full driver droop. I removed the pulley and cut out as much of the tensioner bracket as needed to clear the drag link (clearance is tight!).

The stock A/C belt will no longer work, I ordered the next size smaller belt (Duralast 338K4). After a test fit I welded on a new tensioner bolt hole end. It was a bit difficult to assemble but it all fits together and now fully clears the drag link.

I also made some anti-wobbles from some spare poly bushings, I added them to the frame-side panhard bracket to keep the panhard bar from twisting (otherwise the panhard bar could interfere with the passenger-side bump stop). Now the entire front suspension and steering all clear in every scenario.

 

[JBurt]

I haven't seen a build like this in a long time! Keep up the good work. I'm really enjoying this so far. It's going to be great when you're done.

 

[phattyduck]

I haven't seen a build like this in a long time! Keep up the good work. I'm really enjoying this so far. It's going to be great when you're done.

Agreed. Don't take the silence to mean we aren't watching with great interest - there's just nothing to add!

-Charlie

 

[Team_Jake]

[MENTION=84643]JBurt[/MENTION] [MENTION=139000]phattyduck[/MENTION] Thanks for the kind words!

For the wheels I bought five 17x9 Raceline Avenger Beadlocks (4.5" BS). I wasn't a fan of the machine finish on a white vehicle, so I painted them with Dupli-color Graphite wheel paint (I used primer, paint, and a 2k clear coat, the finish came out decent).

And I picked up five 40" Mickey Thompson Baja Boss M/Ts (DOT version).

I had to order Raceline's beadlock ring spacer (part number RBL17-SPACER), one set for each wheel, otherwise the rings would cone inward.

Assembled together and ready to mount.

 

[Team_Jake]

Moving on to the rear axle, this is where it get's a little weird.

Designing the rear suspension was a challenge, especially when trying to match performance of the front. As can be seen with the front, in order to fit the 2.5" x 14" coilovers, the top mounts are nearly touching the hood. Fitting 2.5" x 14" coilovers on the rear either meant cutting into the cargo bay, or placing the lower coilover mounts far below the axle centerline and slanting the tops of the coilovers inward under the cab. Neither of those options were something I gave serious consideration to. I didn't want to compromise on either giving up the cab space or sacrificing in performance, so in an effort to keep both, I started exploring a variety of cantilever designs.

After designing in CAD a traditional cantilever setup, I wasn't too thrilled with the way it was coming together. My biggest gripe was the changing motion ratio throughout the suspension cycle, it always seemed to switch from progressive to digressive as the axle was approaching full bump, and no matter how I tweaked it, it's motion ratio curve was never smooth.

After a lot of research, I came across a different style of cantilever suspension called a “grasshopper” cantilever suspension (look up Larry Ragland’s 1987 SCORE Championship Chevy S-10 for more info).

In a traditional cantilever suspension system, the coilovers are mounted horizontally with one side mounted to the frame and the other side mounted to the rocker arm. The rocker arm then has a link attaching it to the axle. The "grasshopper" style cantilever suspension system is different in that the coilovers mount to the axle rather than the frame, and as a result they package vertically instead of horizontally. What I like about this design is how nicely it packages and how it produces a consistent motion ratio throughout its travel cycle.

After a little more CAD work, I called up Accutune to discuss the idea with them, and ordered some coilovers. I’m fully committed now, I ordered up the all the steel from SendCutSend and will start building it all soon!

 

[2TH4IST]

Nice work! Wish I could do something similar, maybe with another 4runner. I'm always intrigued by cantilever suspension. I first saw it on f1 and now on rc cars and some rally cars too.

Question, how much weight do you think you'll be adding with all this?

 

[phattyduck]

Nice work! Wish I could do something similar, maybe with another 4runner. I'm always intrigued by cantilever suspension. I first saw it on f1 and now on rc cars and some rally cars too.

Question, how much weight do you think you'll be adding with all this?

Traditionally, most cantilever suspensions are done for packaging reasons or to remove unsprung weight from the suspension. The extra weight of a bell crank and rod are outweigh be improvements in suspension dynamics.

But, as Team_Jake found out, it is hard to keep consistent motion ratios when you try to go very long travel. It is all a compromise.

The setup here doesn't have the the un-sprung weight advantages, but it does have packaging and likely dynamic improvements due the consistency through travel.

-Charlie

 

[phattyduck]

What I like about this design is how nicely it packages and how it produces a consistent motion ratio throughout its travel cycle.

What motion ratio did you settle on for the rear? Hopefully you did some FEA on that cantilever arm - it looks like that thing will see some crazy forces.

-Charlie

 

[Team_Jake]

What motion ratio did you settle on for the rear? Hopefully you did some FEA on that cantilever arm - it looks like that thing will see some crazy forces.

-Charlie

The motion ratio is 1.75:1. Yes, I performed an FEA on the rocker arm, it has a 3.5x safety factor at the force it would take to completely bottom out the suspension, and the spindles are rated 3500lbs (should be able to handle more before breaking, that’s just the rated load). It’ll be strong enough for rock crawling which is what this rig will be doing mostly, if I were doing go-fast desert stuff I’d build it stronger.