Classic Single Cab Build

I've been wanting to build a single cab for years. So long in fact that the style of most builds has changed dramatically and it seems most get towed to wheel. My goal is to build a street truck. No trailers. Drive it to the trails, wheel it and drive home, go for ice cream etc. Because of this a certain amount of simplicity, redundancy, and of course mechanical sympathy from the driver is required.

I picked up a fairly good condition 1999 Tacoma 2wd a few years ago with the intent to solid axle swap it.















Specs/plans:

A lot to unpack here…

Engine

- 2RZ (2.4L 142hp)
- LC Engineering header, and exhaust.

- I never said it would be fast… The 4 cylinders are much easier to work on. Have less power to break parts and the small displacement should get better mileage idling along the trail. The LC Engineering header is said to drop the RPMS the engine makes peak torque at. I justified this to myself as the truck came with the stock cast manifold prone to cracking. The exhaust is mostly just for sound and to replace the old leaking exhaust. I like the sound of a 4cylinder much more than the 3.4’s.

Transmission and Transfercase

- Rebuilt W56
- Gear drive duals 2.28x4.7 with Marlin adapter and gears.
- Custom transmission and transfercase crossmember.
- Dave’z Off-road triple shifter
- VSS on the w59 currently in the truck may swap over. I may need one from an earlier truck to work however.

-This is the classic transfercase setup. I’ve had a single 4.7 case before but never duals. I’m very excited to try them out. I plan to put them where they fit. The W56 being a bit smaller than the r150 may be helping me. It looks like I can raise the transfercase a couple inches beyond a stock 4wd. I also plan to lift the engine engine about an inch. The triple sticks keep the shifters neat and allow me to keep the bench seat for now.

Axles, Suspension and Steering

- 63.25” Diamond Housing to suit stock FJ80 shafts and outers.
-8” 5.29 Elocker (high or low pinion depending upon fitment, I have both to choose from)
- LEAF SPRINGS. 2” lift springs for a 1985 Toyota from OME. I picked 2 of the same side so the arch is the same side to side.
-12” 7100 Short Body Shocks
- T100 oil pan kit
- IFS Steering box, I’ve had one from my old truck. Already tapped for hydro assist.
- Leaf spring 70 series Land Cruiser pitman arm (it’s long)
- Low steer using a ruffstuff Inverted T steering kit with a bent drag link to clear the leaf springs. (Up travel, no to minimal frame cutting)
- 1” x 10” hydro ram limited to steering travel required.


- Diamond Semi-float housing
1/2” narrower than standard Tacoma width. (Fits the dimensions I’m going for. There’s enough spline on the stock shafts to make this work if I need to trim them down)
8” Elocker 5.29
- LEAF SPRINGS All-Pro 3” standard leafs.
- 12” Bilstein 7100 Short Body Shocks

The suspension was tricky to figure out enough ahead of time to believe it is going to work for the height I am shooting for and the uptravel I want to get out of it.
It took some serious web wheeling and laying under the truck with a measuring tape.

The front suspension will be a Deviation from the standard SAS. A few key points that will help keep the truck low and drive-ability good.

- The drop hanger will drop the Spring eye 3” from the bottom of the front frame. It will be moved forward a bit more than standard to facilitate the axle being kept centred on a spring with a 45” length and a 22.5” front section.
-Springs will be mounted at 31.5” spacing. (Standard Toyota is 29”)
- Standard SAS Shackle tube through the frame ahead of the Body mount.
Doing it this was keeps the mounting points as close to level as possible. Combined with having the axle centred on the leaf springs (front to back) reduces the amount of driveshaft plunge, reduces brake dive and should also help with unloading on climbs. Even with these changes the axle will still have a slightly rearward axle path until the spring goes negative. The 31.5” mounting width helps place the shackle on the frame and gives clearance to the elocker diff.

The rear suspension will be pretty standard but I want to ensure I use a shackle length long enough to work effectively with the spring growth. This means the shackle will be about 5.5-6” long. I may run slightly longer and run the mount through or above the frame to adjust ride height and prevent the rear spring eye from being too low.


- Brakes: Stock 5 Lug Master is already 1”…. Bonus!
-FJ80’s already have fairy large brakes and thicker rotors than even the tundra brakes swap. They’ll fit a very low backspacing 15” wheel. (Thinking this would be good for a snow wheeling tire setup)
- The rear will be the standard semi float drum setup. I may add a little extra leverage into the linkage to make the ebrake have a bit more holding power.

- I really wanted to try being narrower in the rear as most drag axle buggies do this to improving the turning circle to avoid cones (or trees in my case). I would like to implement some cutting brakes on the rear axle but the bench seat will have to take a hike first.

It’s not so much different that a set of wheel spacers can’t be used to tune it out if it is not working out for ruts when snow wheeling or v-notches in the rocks.


Wheels and Tires:
- 37" Tire
- 17x8.5” -19 offset Raceline Avenger Beadlocks (weigh 33lbs each!)

37’s are the standard on Toyota driveline and I don’t want to push the limit. Going with a single cab and staying light weight just makes them that much more suitable. I also have a dream that I can cram a 37” spare under the bed. The frame rails are wide enough, the length is there and if I remove the factory spare cross member and put the tire up to the bed floor it should’ve hang down much differently than stock.

The wheels were chosen in an offset to keep the truck as narrow as reasonable without limiting steering. The FJ80 axle can turn about 35° before the felts contact and I want to preserve that.

I want to keep most of the tire tucked under the body. Since the front is wider I have some fiberwerx 3.5” fenders. They seem to measure only slightly wider than a set of factory flares for the front.

I'll be shooting for about 19” belly, and a 107-108” wheelbase. Outside tire measurements should be about 77” front and 73.5” rear. Target weight is 4000lbs

I can’t promise steady progress, but this thread is to keep me accountable and log my progress.

 

Progress up to this point.

I’ve been keeping parts from my 1985 truck and a few parts trucks for a new build for about 10 years now, while I went to school, got a red seal, bought a house etc.

My 1985 had an r151 which I regrettably sold. But I still had a spare low mileage W56B. Unfortunately the transfercase and transmission bolts were so corroded it ruined the rear case of the transmission when splitting them. So I rebuild it anyways.



Running the R151F in my 1985 allowed me to run a 23 spline 4.7 single case. At the time I ordered the gears Marlin was out of the standard gears so I got the competition 4.7’s on sale. Sweet.

After my 85 I used its case along with a Trail-Gear Verso kit to flip the case and bolt it in my 1996 4runner. Using the case I kept from my 85 and the spare one on the w56 gave me everything I needed for duals.

onto the teardown…


Unfortunately I found an issue I had suspected. I while back I read on the forums that Trail-gear modified one of the stock gears for the verso without and heat treat after machining. I’m no expert but I believe these gears are case hardens so once you machine them past the hardened layer your back to regular steel. Here’s a picture of that issue. My case had probably 15000 miles on it.





I don’t need these parts but it makes the Verso kit a paperweight.

Here’s the rest of the cases going together. The Triple shifter will need some work as none of the shifters are in quite the right spot. Everything is steel so easily modified with a MIG welder and a grinder.

 

Axles.

I’m a Toyota nerd through and through and for as long as I’ve had a Toyota truck I’ve wanted Diamond axles for it. There’s a pretty good chance if you have custom axles I’ve sent you a PM or message on Instagram quizzing you about your axle width, wheel offset, what you like about it etc.

My goal was to be just wide enough to maximizing the steering of a Toyota axle, reduce the scrub from spacing out a stock housing and still be as narrow as I can so it looks okay on the street.

I had a pile of mini truck spares and originally the plan was to run IFS hubs front, full float rear with 4runner disc brakes and internal drum Ebrake. I initially contacted Brian at Front Range Off-road and things were looking good. We sent a few emails back and forth and then silence. I couldn’t get a response even when I request a total and that I would like to place an order. In a desperate attempt to get in the queue for housings as I already knew they would take a while I placed an order on the website and sent an email regarding the remaining parts. I followed up every few weeks but I received no response for about 6 months. Then I received a simple reply that they would get to me soon. Sometime last fall I learned that someone had recently received a housing that they had ordered 2 months prior. I was upset, and sent an angry email. I received a phone call from Brian the next day and we hashed out the final details.

Sometime in the middle of all of this a FJ80 Elocker axle popped up for sale and I purchased it knowing the width would be close to what I need and it would have no custom parts that may be hard to track down.

I specd the front housing to suit the fj80 shafts and outers. Bigger birfs, trunion bearings and knuckle balls are all a bonus of going to an 80 series axle. Not well known is that they have a higher KPI (13° vs 9.5°) and therefore a much better scrub than a mini truck with IFS Hubs. I determined that with the wheel offset to create the width I wanted I would have the same scrub radius as a stock FJ80.

For the rear, Brian seemed unsure about the rear full float stuff being available. Not wanting to wait any longer and fearing custom parts may be hard to replace in the future I switched to a standard semi-float with drums. The housings themselves provide so much support that the durability of the components in them goes up. I’ve never broken a stock rear shaft so I am not too worried about this. However it is known Tacoma axle shafts can bend at the wheel mount surface so either 4runner or chromoly aftermarket shafts will be swapped in.

After all that, they still took another 2.5 months to get. Really sucks to go through such an ordeal but over the last year I’ve had a lot going on between changing jobs, buying a my first home and moving 400km. I didn’t have the time to work on the truck too much anyways.

Here they are.

 

Some Inspirational photos.

 

This is going to be good!

 

Hell yeah. Love a 1st gen regular cab sas.

 

Stoked to see this thing finally being built dude!!! Keep up the progress!!!

 

I’m at a point now where I’ll be making more steady progress so it’s time for an update.

Picked up wheels and tires.







The wheels are 17x8.5 -19mm offset. This works out to about stock scrub radius on an 80 series axle.

I went with 37” KM3’s. I like the look and the narrow tread width. I’ve had good luck with BFG’s in the past despite others experiences so I decided to go with them again.

Mocked up on a stock 80 series housing. The knuckles turn 35° give or take when the wipers start to smoosh. The blue line represents the outside edge of the leaf spring. The rounded profile of the KM3’s should really help maximize the steering angle.




Moving on from the wheels and tires I started on the passenger front spring perch. It’s a bit tricky to come up with a leaf spring mounting solution since it rides up the centre section.

Originally I had planned to make these stubby u-bolts work with some kind of retaining device.


After shaping the perch to fit the housing at the width I needed I realized I just didn’t have the room.



Plan B…








I drilled and tapped a chunk of 1” square stock, and contoured it to fit the housing as well. I went 1” over something 1/2” like the Ruffstuff u-bolt eliminators. I was concerned the mild steel threads would strip much easier than the hardware that threaded into it.

Since this moved the mounting holes on this side over, I had to create a new “special” U-bolt plate with offset holes.

 

Drove the truck around a little bit for the past couple weeks and then yeeted the rear axle out to get things under way. Mounted the 3” All-pro springs and rear housing.

I have to cut the abs rings off my Tacoma axles for mock up and the centre pins don’t fit the u-bolt plates.

 

Mad FLEX!

It's coming along!

 

It’s about time to post another update as I’ve made I bit of progress on this thing.

Starting with the front leaf setup. I’m running stock length front leaf springs which are about 45” long and the centre pin is positioned exactly in the middle of the spring. I’m specifically running the old man emu 2” front lift springs for a 1985 truck/4runner

By having the centre pin in the middle means the changing arc of the leaf will not effect the caster and keep from pointing the pinion into the dirt as severely on droop compared to a spring with the centre pin biased towards the front of the spring. This negates a lot of the disadvantages of a rear shackle setup.

The front half of the spring is about 2” longer than a RUF or trail-gear spring so the hanger is located a bit farther forward. A slight hit to the approach angle but won’t stick out as far as the winch so I’m okay with it. To me it’s worth the trade off. I like to think of the front half of a leaf kind of like a control arm so having a slightly longer control arm is good with me.

The rear half of the spring is much shorter than a common aftermarket option which I think is a good thing. The rear half of the front spring causes lots of problems on steep climbs and results in unloading and the front axle trying to walk out from under the truck. I’m sure there are other disadvantages as well. If you look at a stock 1985 front leaf spring all the leaves support the main spring almost all the way to the shackle. I’d like to modify the spring clamps on these springs to keep the rear half snug to the main leaf even when dropped out (no fanning of the leaves) to keep the spring more rigid and less likely to wheel hop.

The spring also has minimal free arch which I think is another compromise and not what most people do. It could have low spring rate, tonnes of free arch and have gobs of droop like a coilover setup but we’re working with leaf springs here. I’m not trying to make it look like it has coil-overs at the expense of wheel hop prevention and stability. It will keep the front end lower on steep climbs without a suck down winch as well. Since my steering will(should) allow more up-travel I intend to send these springs about 3” negative. Starting with a leaf that’s closer to flat in theory should mean less stress at -3” arch. Stephen from off-road design thinks this way as well and most of the Chevy sas’s with leaf springs are almost flat at ride height and go well into negative arch. It just works packaging wise on a frame like this.

This setup requires keeping the shackle angle relatively tame as the jacking effect when the leaf is going negative and pulling the shackle back can be horrendous. In fact if you set it by the old advise of 45° at ride height, it can keep the spring from going negative period(not to mention how digressive that makes the spring rate).
I had downloaded the SAE leaf spring manual and doing some very rough math determined that having the shackle 30° when the spring is flat will result in a shackled spring rate of approximately 150% of the leaf springs rate. Kind of like hitting the coil stopper on a coil over and getting into the stiffer spring rate. The leaf spring is rated at 209lbs and should be about 180lbs shackled at ride height and a little over 300 at bump.

I didn’t go overboard tucking the front spring eye up because I am trying to reduce geometry changes throughout the travel and keep the tire out of the firewall. Another disadvantage to tucking it up high is you have less room to fit a pitman arm and tie rod end. Instead I did my best to tuck the rear eye up as high as possible to get the flattest spring I could. Look at most OEM front leaf setups and you’ll find they do the same.

I wanted to use the Sky Manufacturing Crossmember that I used on my 85 but they only sell it in Toyota width. So I chopped it in half and rigged it up with 9/16” ready rod. (No 18mm bolts for me)



Since the spring is shorter and further forward the shackle ended up further ahead on the frame rail meaning I could just get away with a regular sas frame tube and both spacers on on side of the spring. I wanted to be as accurate as possible during this step so I used 1/4” rod to check my pilot holes, the same 1/4” rod to create a longer pilot and an extended length hole saw to keep the drill as true as possible. Once the holes were drilled a piece of 1” conduit works to hold the frame tubes in alignment.

 

Next I did a quick and dirty swap of the knuckles from the stock fj80 axle onto the diamond to make it a roller.







It was sitting a little high up front and I had some room between the spring eye and the frame… so I made myself a lowering kit.






My spring perches are tacked at 1.5° so add that to the measurement in the photo. The frame is pretty much level now with no transmission, winch etc. I should be right at my goal of 5° when it’s all together.

 

Testing steering angle. An FJ80 knuckle can turn about 35° before the felt retainers contact the knuckle ball. I was happy to see I had gone wide enough to allow all of the steering I had available with a little wiggle room. For comparison this is about the angle a stock ifs truck can do and about 5° more than a mini truck knuckle can do without deforming the felts.









Next I tried on the front fiberglass to see how they evened out the front vs rear tire coverage. Pretty good.






That’s about it for now

 

Badass.