The Rock40 Build

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After completing this trip recently https://forum.ih8mud.com/threads/3-...year-old-fj40-m416-combo.814678/#post-9314419 I've had several request to document the mods on my 69' FJ40 and 69' M416 trailer.

There is a thread on Pirate from 2-3 years ago but if you don't visit over there this is new. Here's how it sits now.
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Without getting too long winded, I've had this truck for the past 14 years and I purchased it when I was 19 years old. Like most 4WD things made by Toyota, it began a slow transformation from "bone stock", non-running to its current state.

It was once spring-under with OME's, then spring over with FJ60/FJ55 leaves. It was tall, so terribly, terribly tall and this was the common result.....

Tillamook 05' 04.JPG


A side pic shows just how tall it actually was

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It tipped, a lot.....
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Regardless of its knack for flopping over, I drove it like this for many years logging almost 25k with the truck. I never trailered it anywhere and part of the adventure/fun of going wheeling was the road trip itself.

The factory 1F was ditched in 03' in favor of a 5.7 Vortec V8 from a wrecked 96' Suburban. Behind that, I coupled an ancient (but rebuilt by me) SM420 transmission, a now extinct Rockbox (3.4:1 gear reduction) from AA and the stock Toyota transfer case. The front/rear axles were more or less stock with the exception of disc brakes, ARB's and Profield birfields in the front. With a crawl ratio around 230:1, it's amazing I didn't break more stuff.

In 2011, I was tired of the leaf springs and the overall suspension setup. I had a set of front/rear axles from a 93' FJ80 in my shop and I convinced my neighbor (Ethan Taylor) that it would be a great idea to 4 link the rear using the FJ80 FF axle. This would kick off 18 months of CAD design and fab work.

FJ80 FF Axle.jpg

Donor axle prior to cutting all the crap off
 
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I wanted to build the rear around using a set of Currie 4" coil springs designed for a late model TJ. Unfortunately, this is the best photo I have after the axle was cleaned up and the brackets started going on. Everything was CAD drawn and plasma cut by Ethan.
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These show how the rear went together, all in all quite simple. The stock crossmember was removed and a new one was fabbed to mount the rear shocks. The rear cover is a Blue Torch Fab model (for a semi-float) which was permanently welded on. The links themselves are 5/16 wall with Currie Johnnie Joints on both ends. The factory dis brakes were retained minus the parking brake components. I converted all the brake lines to 3AN for trouble free/leak free use.

More to follow.....all this posting makes me cranky!
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RAYJON

Get a bigger hammer..
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good dog, he guards cruisers ....
 
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Great work! Fantastic cruiser, I was following your work on Pirate too.

Man, it's crazy how many folks remember the build on Pirate from years ago, pretty cool :) met a guy randomly in MT who stopped to chat after he recognized it, small world I guess
 
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LOL, I wondered :hillbilly: That photo is from CTW 04' according to my notes!!
 
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Few more things on the 4 link rear........

Daystar Stinger bumpstops housed inside coil springs, this is just the can, the actual bumpstop was added later during final assembly
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Upper link bracket bent/welded up

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There was zero room for sway bars in the front so this was the solution. We used one of the universal fit kits from Currie and the torsion bar runs over the top of the frame. This shot is looking toward the rear of the FJ

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Bit the bullet and went big on the front end. Dynatrac Pro Rock 60, w/ARB, 3.7 gears, Dutchman Axle 4340 domestic inner shafts, 35 spline chromo outers, 6 lug conversion hubs.........it got pricey.
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CAD drawing of the front axle bracket which incorporates both the upper/lower link along with the coilover shock (in red)

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Front suspension is a 5 link w/hanhard bar, 14" RaceRunner dual rate coilovers
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Upper handhard link which is outboard of the frame and slightly forward of the front axle housing
 
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I found several more old photos when the truck was tall and sprung over :beer:
_MG_4682.jpg

From Bend, OR in 04' or 05' I think

Tillamook 05'.JPG

Little Rubicon in the Tillamook National Forest, Tillamook, OR. This obstacle doesn't look like this anymore.....

Alcan.jpg

Alcan HWY, 2010
 
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Back to business :D
CIMG3552.jpg

All the suspension/axle stuff was sent off to a local powdercoater/sandblaster.


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Rear end assembled

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Front axle assembly
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CIMG3557.jpg
 
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I should probably mention that the front suspension required some frame cutting/notching.......

At full droop, the front axle moves laterally toward the drivers side and the coil shock was going to bind up in the frame big time.
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kind of unsettling.....
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Welding in the patch

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Completed patch and coil shock. You can see the direction the axle travels as it heads toward full droop
 
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Some beautiful welding.

Thanks, Ethan is the guy with the crazy fab skills :hillbilly: All the weld bungs on the joints were triple pass and TIG'd, the frame/axle brackets were all MIG. I think it took him something like 8 hours or so just to do the bungs for the Johnnie Joints.
 

kling-on

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Very nice
 
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That is more or less the long and the short of it. Throw in a PSC hydraulic ram, GM 1 ton TRE's, disc brakes, a T100 brake master cylinder and go. Suspension wise, zero issues in the past 3 years or so. Here's some pics....
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Walker Valley, WA

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Bluitt Pass, WA You can tell it was in the 90's that day just by looking at the dog...





























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Moab, UT
 
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Here's some videos which show the suspension in action, smoooooooth





http://api.***.com/api/click?format...=Walker Valley April 2012 Version 2 - YouTube
 
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Yes, the wheelbase sits at exactly 102" now which I think is 12" longer than a stock FJ40.

The question about a 3 link came up before and the answer boils down to space. The FJ40 just doesn't have any (enough) to make it workable; at least on this particular truck. This problem was aggravated by the huge casting of the PRO Rock 60 also. I know lots of folks have done 3 link fronts but we were both shooting for a truck with a very low stance/low lift so it wouldn't work.

Here's how Ethan described it:

"Originally I had the front as a radius arm setup because there is NO room on the inside of the frame for a upper link bracket, the radius arm setup bound HORRIBLY so I had to scrap it, came up with the 4 link idea and made some paper mockup brackets and it STILL had a ton of bind.
The key is to get the axle NOT to rotate at all as it travels, if it rotates as it travels down both sides will move together just fine, but when you drop just one side the upper link measurement will change side to side. The frame end brackets mounting points have to be perfectly placed, and unless you are the luckiest person in the world it will never come out right by guessing.

You can draw it out on a large table or the ground by swinging a arc from a point as your lower link mount. You will need to know how long a lower link and how much of a bolt hole spread on the axle you will have. Vertical from the frame end lower hole measure up the same distance as your bolt hole spread, mark this spot and swing another arc. You now have the travel plane of the axle with no rotation.
Now mark two more points on your two axle-movement arcs, in the same "vertical" plane as the original two axle end holes (oh yeah, mark the two axle end bolt holes on the arcs as they would be at ride height or max up travel) if you follow down the arc lines and mark on the same vertical plane they should still be the same distance apart.

Now swing a arc from your upper mount hole mark the same radius as length you want your upper link (shorter links will move the frame end upper mount position forward of the lower link mount and closer together) For this project it has a 35" lower and a 32" upper. If you swing a arc from the upper axle end mount at both up travel points and lower travel points the point where the two arcs intersect will be the location for your upper frame end link mount.

Put the panhard wherever you like."

Does that clear it up any? :grinpimp:
truck20.jpg

Here's a photo of the CAD drawn swing arcs.
 

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