Build 86 Xtra Cab Build (4Wheelunderground 3 link front, 4 link rear and 3.4 swap)

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@ntsqd, :hmm: So....have the upper horizontal tube come straight back and through the cab. Where I have a joint.

And.........have another joint down at the base plate with a straight piece of tube between the two joints?

Here's a photo edit attempt on my phone to illustrate.

I understand the concept of the bushings allowing enough movement to prevent fractures from metal fatigue. What I don't get is how the tube is not just a moving linkage if I flip and forces are trying to fold my main hoop either forward or backward.

IMG_20250901_161745956~5.webp
 
It isn't, but there are two things going for it. The extension tube is short enough that it isn't much of a lever and in a catastrophic event the cab's own structure is going to be working with it to keep everything from collapsing.

FWIW, seeing from that angle I think that the tie-in at the frame needs to be much further back. Gets back to that vector math stuff again. With the back-brace tube that vertical must of the load put into the upper joint is going to be vertical and their effectiveness at resisting the cage parallelograming is pretty minimal. With the back-brace tubes at something more like a 45° the vertical component of the load is reduced and the anti parallelograming effectiveness of the back-brace tubes is greatly increased.
 
Just a thought to ponder; find one of those old school plastic bed liners that will fit the truck and run it as the whole inside of the bed with the existing bedsides held in place by a simple tube structure that also supports the bed liner. I've had this idea floating around in my head ever since a friend built a bedsides-only pre-runner that he suddenly needed to be able to use as a truck.
 
@ntsqd Thanks for the pics. Definitely helps. I had to move the fuel tank to make room for the backstays and the diagonal bar(s). Planning to tie into to the frame where you suggested. Where the frame plates have the tube crossmember between them, just in front of the shock hoops. Going further back will interfere with my spare.

I'm not sure how I will attach to the frame yet. I "assume" it shouldn't be welded directly since the rest of the cage is bolted to the cab floor. The cab is on poly mounts so I considered the same poly body mounts. (I have a whole set) I cut the cab mounts off my other frame so I had the idea that the cage could still "move as one" if I attached it to the same body mounts. However, it wouldn't be attached to the same floor that the front half is sitting on. If it were a 4Runner, it would be. I'd just bolt it down and be done.

I haven't given up. Life is a bit challenging right now. Feels like getting pummeled in the surf. Every time you get up, another wave hits. Could be worse though.
 
I know how that goes. No worries.
I would use those same urethane 'Hega' joints at both ends. Cross tubes on the ends of the stays with bolt tabs at the rear of the cab and on the frame.
 
I had a big box of new poly bushings in various sizes given to me. Basically spring and suspension bushing kits from Energy Suspension and Daystar. Would a thicker bushing be better as far as allowing enough flex to prevent cracking welds or tubing? Some bushings have sleeves for the bolts, some without.
 
Anybody still following? I'm still not able to really get to work on this but SOON.

Last time I worked on it I pulled the fuel tank. It's in the path of my back stays. Yeah, after all the farting around trying to mount the tank to my frame. It's going to mount in the bed all the way forward.

Last year I had bought my spare Sticky Mickey tire during a black Friday sale but I was sent a regular DOT tire. The seller took it back, paid the freight but wouldn't send me the correct tire. Well I found another deal this year and got the correct one.

PXL_20251207_224317255.webp
 
But even better, these JUST got delivered. Yep, on Sunday. Looking forward to get back on this.

I'll put my 2nd gen 4Runner buckets up for sale.

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We not getting any younger but still following 🤠
 
Glad to see some updates! This is one of my favorite builds
 
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