Builds 86 Xtra Cab Build (4Wheelunderground 3 link front, 4 link rear and 3.4 swap) (11 Viewers)

[aztoyman]

I'm going to abandon the fabricated tank under the bed idea. I'd have to use ALL the available space to still have a small fuel tank. The nail in the coffin is that it cuts off the space I need for my exhaust.

Mounting the stock tank halfway through the bed floor also blocks exhaust routing and is still a big lump in the middle of the limited bed space.

I can put one behind the axle, below the bed if I protect it. It will require routing the tail pipe out the side in front of the driver side tire and it might be tough to fill with the spare mounted on top. Still an option though.

 

[aztoyman]

I just took the time to level out my truck and set it at ride height to get an accurate pinion angle check.

At ride height, My drive shaft slope is 14 degrees and the pinion flange is pointed up 16 degrees. So a 2 degree pinion angle but it's the WRONG direction IF on a leaf spring truck.

@ full droop 23 degree slope and pinion flange up 17 degrees. That's a 6 degree pinion angle and it would be worse if I turn the pinion down 4 degrees at ride height.

@ full stuff 9 degree slope and pinion flange up 12 degrees so pinion angle of 3 degrees.

I emailed Shawn @ Tom Wood's Drive Shafts to ask about this and he called me right after I hit send. Wow that's fast. He said to leave it right where it is on this 4 link so I'm happy I can finish up the rear axle without cutting my tack welds and futzing around rotating it. I'll get the Ruff Stuff Back Brace fit up and welded on and then work on the brake cables and hard lines.

 

[aztoyman]

Ok I mocked up two exhaust options. Which one I go with depends on if I run my fuel tank behind the axle.

Here's the option if I have a tank back there.

Everything clears. I have access to my bolts for my links and I'll be able to remove it if needed. The level is where the back of the cab will be.

It will have to come through the side of the bed. Saves me from trying to body work the big dent out that's there. Maybe I'll put a huge ricer exhaust tip on.

 

[aztoyman]

Here's option 2 where it can run all the way back if there's no tank in that space. Yes it's too high right now to go under the cross brace. It's just stuck together for mockup.

 

[gnob]

i think whatever you can do to dump it further back.
Definitely don't want it coming out the bedside right next to your ear.

 

[aztoyman]

gnob, you have always given me sound advice.

I'll consider that but I will be disappointed if I can't run my ricer exhaust tip. I do like to cruise with my window down.

 

[aztoyman]

Hopefully the last time I have to pull the rear axle for a while. Time to get it welded in. Been tacked for TOO long.

I'll have to custom fit the Ruff Stuff Back Brace once this is done. Slow going right now so all I have today.

 

[aztoyman]

I got the 4WU brackets all fully welded and started on the Ruff Stuff Back Brace. Centered the tube over the fill plug first and tacked it.

 

[aztoyman]

Used a shape transfer tool over the 4WU bracket to mark the back brace and cut it to fit.

 

[aztoyman]

The brace is a pretty good fit as is but I'm picky about fit on my axle housings. I think a lot of the bent after welding problems are because of welding large gaps. It pulls a lot when the weld cools.

I did quite a bit of grinding and bending for a tight fitting weld joint without having to clamp it into position. It layed in position really nice and I tacked it on. The bottom of the fill tube was fully welded prior. There are two end caps that will get welded on as well.

 

[aztoyman]

Now that's a lot of beef supporting the axle housing. However, just like the front axle, it's still weak on the ends. So I'm going to make gussets similar to what I did on the front and reinforce the ends. Look at the gap between the flange and the brackets. If it's going to bend, it will happen here.

 

[mustcamp]

What I think I'm going to end up doing is a fuel cell between the shock hoops and against the tire. It would be protected by the hoops in a roll over and even if I took a hit from the rear, the hoops stop further forward travel of the tire. It would be easy to fill in this location.

RCI has 3 models that would work. The 19 gallon option is just a plane aluminum model and I'd need to run an external pump or modify it for an in-tank pump.

There's a 17 gallon one that is tall and skinny and would save bed space. External pump.

I'm kind of leaning towards the 15 gallon Rock Crawler fuel cell for safety reasons. Also requires external pump. It's close to the dimensions of the 19 gallon model but this is the poly inner tank in a steel container.

I'd rather have the weight lower mounted and I barely have any bed space but I don't have many options.

Speak up if you have any other ideas.

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I'm leaning towards the Ford van tank. It is 1 inch shallower and the I think the inlet would be easier to keep under the bed or in my case the floor. I want to use an 80 series rear axle I have... so the gas tank has to go some place else not in the cabin as with the offset diff I will have driveline clearance issues. Then moving the tank also opens up the thought of linking it.

also lots of stuff still up on Pirate 4X4 this is just one I saved.

Who used a Ford gas tank in the toyota?

Fit right between the frame rails where the spare goes? What tank is it?

www.pirate4x4.com

 

[aztoyman]

@mustcamp, thanks for the links and suggestions. I narrowed the back half of my frame to get the shocks to work. I bobbed the bed 12" as well. The space behind my axle is only 26" wide.

I found some tanks that will fit........kinda. The axle will hit them at full stuff unless I cut the tanks and angle the bottom front in to clear the axle. They are only 15 gallon tanks to start with. They are also 10 or 12 " deep so they will hang well below the frame rails. I don't know if that would be an issue or not.

I appreciate the ideas. Keep them coming.

 

[ntsqd]

Maybe go at it the other way around, decide what range you need it to have, rough guesstimate the MPG off-road, and then arrive at how many gallons is required? I'm getting the impression that a 10 gallon tank at 10 MPG would leave you with a comfortable safety margin, but there's a lot of stray electrons between here and there and I could easily have it wrong.

 

[aztoyman]

I can do like Smokey Yunick did and have huge fuel line looped around to get around the tank size limitations.

 

[ntsqd]

How many even know that story any more?

 

[aztoyman]

Here's the space behind my axle at full stuff. The bed and bumper will be further out behind this. This last rear cross member is where the rear most bed bolts go and it's about even with the rear tires.

That space between the rails and up to the round tube is 25" x 25" Obviously the front would have to angle back to clear the axle.
Dropping off a step might not even be an issue. If I put a fuel tank in here, how far down do you guys think would be reasonable? Where I won't be bashing it in.

 

[mustcamp]

This is how I extended the Ruffstuff rear truss to try and keep the axle tube from bending outside the spring hangers. I had a friend with a large brake bend up the same profile and I extended the truss all the way to the axle flange.

 

[aztoyman]

I like it. I am copying this idea.

 

[bkg]

@mustcamp, thanks for the links and suggestions. I narrowed the back half of my frame to get the shocks to work. I bobbed the bed 12" as well. The space behind my axle is only 26" wide.

I found some tanks that will fit........kinda. The axle will hit them at full stuff unless I cut the tanks and angle the bottom front in to clear the axle. They are only 15 gallon tanks to start with. They are also 10 or 12 " deep so they will hang well below the frame rails. I don't know if that would be an issue or not.

I appreciate the ideas. Keep them coming.

I was going to suggest an aftermarket Samurai tank... width would work, but I'm not sure depth will. Petroworks is about 12" deep on their 15 gallon tank.