Build The LF40 Wheeler Build - Twin Turbo & 8 Speed Auto FJ40

[cruisermatt]

I just feel a 40 benefits more from having the rear axle pushed back more then you can with leafs, especially without the weight of the engine back there. And with links you don't need frame past the axle. That's what I'm going to do for my build anyways which is going to be kind of similar specs but more lightweight/crawling oriented. Widened 60/80 axles, 4-link rear, backhalfed, leafs up front with shackle reversal (thinking 52" XJ leafs with short side forwards), about 108-110" WB. I'm still in the parts collecting mode though.

What's your wheeling experience? It might be worth it to just tune what you have for now and get a feel for how a truck feels offroad and get some driving experience in the rocks before you start going crazy with links, SOA, etc.
leaf springs that are set up right can offer very good articulation and ride quality, especially when paired with the right shocks.

 

[DangerNoodle]

I just feel a 40 benefits more from having the rear axle pushed back more then you can with leafs, especially without the weight of the engine back there. And with links you don't need frame past the axle. That's what I'm going to do for my build anyways which is going to be kind of similar specs but more lightweight/crawling oriented. Widened 60/80 axles, 4-link rear, backhalfed, leafs up front with shackle reversal (thinking 52" XJ leafs with short side forwards), about 108-110" WB. I'm still in the parts collecting mode though.

What's your wheeling experience? It might be worth it to just tune what you have for now and get a feel for how a truck feels offroad and get some driving experience in the rocks before you start going crazy with links, SOA, etc.
leaf springs that are set up right can offer very good articulation and ride quality, especially when paired with the right shocks.

I'm not super experienced, though I can get around ok. I'm building this rig for may dad though. He is really experienced driving and has gotten that 40 a ton of places that you would'nt think to be so doable. I'd like to shoot for a roughly 102-105" wheel base, and after looking at @Lil'John s post, I think it would probably be better to link the rear, not the front, if the plow is going to stay.

 

[DangerNoodle]

I will second this from my first FJ55s experience. 4.88s plus 35s behind a v8 and NV4500 is too deep. I yanked the gears and went with 4.56 gears.

You will have a LOT of fun cutting all those brackets off the rear Fj80 axle housing. It took me two days to grind one clean. Pain in the butt.

If you are going to keep the snow plow, you might think about the linked front end again. That is a ton of weight hanging over the front that when removed will make your spring choice in the front 'junk'. I've got a similar plow setup that I'm tinkering with on my 3rd FJ55. The blade alone was ~275lbs, the hydro ram was ~55lbs, and the frame mount was ~95lbs.

Like you, I'll be linking the front because "free" except for the springs. I'm still scratching my head on how to do the springs.

The cruiser never really goes that fast, and with 37" and crawling, I think that being able to crawl pretty low would be better. This isn't a daily driver, it is usually just for plowing at speeds lower than 30mph, and wheeling. It may have the occasional jump on the roads to get to a trail, but it will be mosly trailered around for longer journeys.

With linking the front end, you make a really good point. Do you think that coils on the front would do any better, and then just use the existing coil buckets on the 80 axles and slap something together for the front?

 

[DangerNoodle]

I'm not 100% sure what my spring solution will be in the front especially with the plow. My 'cheap' get it mobile is probably going to be 1/4 elliptical using some 1 ton Ford springs(free) I'll cut in half I might track down some cheap air bags to account for the extra weight but I'm not 100% sure. When I feel rich, I'll go coilovers although I have a set sitting on the shelf for another project

FWIW, springs are springs are springs whether they are leaf or coil. Coils can give you a more progressive rate especially if you do longer coilover shocks where you can have two spring rates. Leafs are somewhat easy to get an overload which might help with the plow(only in use at heavier loads)

For gearing, my experience crawling with my old FJ40 with 4.11 gears, 35" tires, and an SM465 was it needed just a hair lower.

On my plow FJ55, I'm currently at a cross roads with gears. One axle has 3.54 gears and one axle has 5.86 gears I've got a set of 3.54 gears hanging around that I could swap over. The 'big' difference is my plow 55 has a big block Cadillac(472) engine, SM465, and 35s. All the reading I've done about big blocks say they will have 'insane' off idle performance so I'm considering the 3.54s. If I do 4.1 gears in the split case, that gives me a 10% underdrive in high which would effectively put me at ~4.0 gearing in the axle.

I'm 35 miles from the Rubicon so I need a little bit of 'speed' available. But not too much with the ~45mph roads

Leafs with a SOA on each axle would be pretty easy for me to do, cause I have the stock springs. A linked rear would be great cause I could move the rear back much more easily. I need to consult the bank (my dad) and see exactly how much he is willing to put into this build.

It's awesome that you live that close to the rubicon. That has been my dad's dream to do the rubicon, and the plan is to do it when this cruiser is finished. It was originally from Cali (I am too), but he was never able to go and do it. I'm hoping to be able to do it within the next couple of summers.

 

[DangerNoodle]

Quick little update. I got the axles moved into the garage with the hopes that my dad will pull them apart since I'm back to school.

The front pinion bearing is shot. Hopefully, it hasn't worn into the housing, but I don't think that it has. The rear looks good. My dad added some daylight into the rear rotor with the backhoe when he originally got them, he wanted better cooling I guess. I am not looking forward to cutting off all of those brackets on the axles. Hopefully I can find a plasma cutter to speed up the process.

I also ordered some new wheels that will better match the paint. They were on sale for $104, and look really similar to the wheels on there now.

Pro Comp 69 Vintage Polished Alloy Wheels.

 

[cruisermatt]

I have seen a lot of people just jump into a build and go nuts with links, SOAs, etc and then find out it's not for them. I'd start simple and maybe play with shocks, shackle angle, etc and tweak what you have first and do things in stages and get your feet wet. You have a lot of years of building trucks ahead of you. (I do to, im only a few years older).
Also cutting all those brackets off sucks. I've done it twice

 

[DangerNoodle]

I have seen a lot of people just jump into a build and go nuts with links, SOAs, etc and then find out it's not for them. I'd start simple and maybe play with shocks, shackle angle, etc and tweak what you have first and do things in stages and get your feet wet. You have a lot of years of building trucks ahead of you. (I do to, im only a few years older).
Also cutting all those brackets off sucks. I've done it twice

That's what I'm thinking so far. A simple SOA to start, and the axle swap. Then see where to go from there. How hard would it be to link the rear? If I am cutting off all of the stuff off the axles, would it be worth taking the time and energy to do a rear link?

 

[cruisermatt]

You'd want to cut everything off the axle to link it anyways, I am not a fan of the 80 rear suspension in the slightest

 

[DangerNoodle]

A three link or four link isn't going to be cheap especially if you start using quality parts Even 'cheaping-out', it is expensive. I've got two FJ55s with front links on the build list; one is going to OCD fab guy, one is getting hacked up by me. I'm doing the 'cheap' one and just the link stuff will be close to $1k

Personally, I'd avoid doing a linked suspension unless there is some huge reason or failure to perform issue you are trying to address... a 'tuned' SOA performs very very well.

Here is a shackle reversed FJ40 low SOA using stock springs done in the 90s:
View attachment 2147110
Here is a tuned up SOA from mid 2010s on my FJ55:
View attachment 2147109
The above is 99 Tahoe springs(54") at all four corners with Liquid Industries leaf spring sliders instead of shackles and NO shackle reversal with 35s. I had binding issues before I ran out of flex even with the stock FJ55 sway bar in the back. It fit into a 7' garage with no problems The axles are 60" wide Dana 60s so a bit narrower than the FJ80 axles.

With the SOA, what are the ways to tune it? I'm starting to look at doing just a SOA on everything first, and then if we decide we have a need to link everything, we can. What are the optimal angles for the shackles? I'm thinking of outboarding the springs for extra stability. Would that be worth doing? Also, how are those sliders instead of shackles? Do they feel better or do they feel the same?

 

[DangerNoodle]

For me, the few ways to tune a SOA are:
- spring length - longer flex better and usually softer.
- spring pack count - more springs usually result in stiffer ride
- shackle angle/length (if used) - closer to 45 degree, the 'softer' and better articulation you will get.

The FJ40 shown had stock length 'short' shackles. Nothing special. When I got rid of the shackle reversal on it, I put the shackle through the frame at a 45 degree angle in the front and the spring with a 1" space from the frame. Unfortunately, no picture of that mod

Now, I will never touch a shackle again. The leaf spring slider provides a super smooth ride and won't fight the spring travel; no competing archs. When I did them on the green 55, I did the rear first then the front. On road, it smoothed out noticeably and it handles like it is on rails. I LOVE the ride in the green 55 1000% more than my stock 02 Tacoma; yes, a 35" leaf sprung lifted rig out handles and feels better than a stock 02 coiled front Tacoma on 31s. My future FJ40 project will be getting them once that project gets going.

On outboarding, I can't comment on benefits as I have never done it nor have I felt the need to. The white FJ40 felt stable as is when I did Rubicon and Fordyce. The green 55 has the front springs in stock location while the rear were outboarded 1/2" on each side because the gas tank forced it

Have you had any problems with the pucks wearing fast or getting worn out? With the SOA and the sliders, do you lose much height? Did you shim the sliders to get a good angle on them?

 

[White Stripe]

How would you do the steering with the front soa and a 80 axle? Only thing I can think of is hellfire knuckles which are over a grand for a pair. That's why I mentioned use the radius arms. Also, aluminum wheels like that won't work very well with those tires. It your going aluminum you should get aluminum bead locks. Krawlers don't stick to the bead very well without bead locks, they burp air like crazy.

 

[DangerNoodle]

How would you do the steering with the front soa and a 80 axle? Only thing I can think of is hellfire knuckles which are over a grand for a pair. That's why I mentioned use the radius arms. Also, aluminum wheels like that won't work very well with those tires. It your going aluminum you should get aluminum bead locks. Krawlers don't stick to the bead very well without bead locks, they burp air like crazy.

I'm looking at doing the radius arms right now. How well do the stock 80 arms flex? I've been looking at the ruff stuff long arm/radius arm kit and with the heims joints, it looks like it will flex a lot more than the stock ones. I think I might just try and put beadlocks into the steelies right now, and keep the alloys for plowing/driving. Total Metal Innovations has some pretty good kits for beadlocks it seems.

 

[DangerNoodle]

Here is a picture of the rear slider install plus the offset:

They come with the incline. Also, this picture shows the location of spring eye relative to the frame. My best guestimate is that the spring slider version of a SOA is at least 1" shorter than a complete stock version. As previous picture showed, extremely nice flex and I believe it to be predictable/non-binding motion. They aren't cheap though and the price has gone up

I have not noticed any puck wear in 10-15k miles of use about 5k of that being windy backroads trying to drive it like a slot car
Here is what the front ended up looking like:
View attachment 2147378
I forget if this was pushed to the end of the frame rails or over the front. This picture also shows the amount of travel the puck has when flexing. At full compression, it is all the way to the end.

If I needed, I can get the rig lower by insetting the sliders into the frame.

As I noted, I like them enough to do another set in the rear of my plow 55 and giving serious thoughts of front/rear in the FJ40.

With all the above touting the sliders, another 'tune' for a shackle based SOA that I hinted at previously is to put the shackle through the frame at about 45 degrees with the full weight of the rig on the springs. I did that on my old FJ40 and it provided a pretty good amount of flex. But I could see the 'binding' plus you get left to right leverage/rocking.

Those sliders are looking better and better. Thanks for the info!

 

[White Stripe]

I'm looking at doing the radius arms right now. How well do the stock 80 arms flex? I've been looking at the ruff stuff long arm/radius arm kit and with the heims joints, it looks like it will flex a lot more than the stock ones. I think I might just try and put beadlocks into the steelies right now, and keep the alloys for plowing/driving. Total Metal Innovations has some pretty good kits for beadlocks it seems.

They flex ok. You can check out the 80 section and their are some tricks to getting more flex out of them. Using them will save you a bunch of money. They don't flex anything like a 3 link but its not like the truck won't be capable with the 80 arms. I was thinking of the inner air locks because they lock the inner and outer beads and they aren't too expensive. If you do remove the tires from the steel wheels, have a good offroad shop do it, with the wheel offset they have to be removed on the backside of the wheel or it will damage the tires.

 

[DangerNoodle]

They flex ok. You can check out the 80 section and their are some tricks to getting more flex out of them. Using them will save you a bunch of money. They don't flex anything like a 3 link but its not like the truck won't be capable with the 80 arms. I was thinking of the inner air locks because they lock the inner and outer beads and they aren't too expensive. If you do remove the tires from the steel wheels, have a good offroad shop do it, with the wheel offset they have to be removed on the backside of the wheel or it will damage the tires.

Ok. Good to know about the wheels. With a radius arm setup, do I need to run a sway bar or is just a track bar acceptable?

 

[White Stripe]

Ok. Good to know about the wheels. With a radius arm setup, do I need to run a sway bar or is just a track bar acceptable?

Their are guys in the 80 section running the radius arms without the sway bars. You can ask them what they think. Ive never ran without sway bars on the street so can't tell you. Sway bars are mainly to improve street handling or if your driving fast like a ultra 4 buggy offroad. The 80 front sway bar is a pretty simple setup and would be easy to make work on a 40

 

[DangerNoodle]

With radius arm setup, just like a 3 link, you need a track bar. It locates the axle left to right. Ideal is same angle and length as the steering drag link.

A sway bar is to handle 'left/right' body movement. They are a god send if your suspension is super soft. On my green 55, without a rear sway bar, hitting a bump while going faster than 55 cause butt-puckering body roll.

Good to know! Thanks for the info.

 

[DangerNoodle]

Ok guys, looking for a little advice here. I'm 90% sure that we are going to be doing coils on the front, so that leaves me with a few options. I could run stock radius arms, but I'm not exactly impressed with the flex on those, or even sure is they would line up well on the frame of a 40. I would like your opinion of the Ruff Stuff radius arm kit (DIY Universal Radius / Long Arm Kit). With the himes joints, I know that more will be felt through the rods, and they are not rebuildable, but I think there would be more articulation. I am also looking at the 3-link kit (3 Link Kit with 1.25" Heims) for the front, which I could still run coils with, and then if I need to, could convert to Coilovers later. It also has himes, but I'd just run those till they need to be replaced and replace them with Johnny Joints. I have the budget for either, but I'd like to hear what you guys think of both, or which one would be better.

 

[DangerNoodle]

I can't comment about either kit from experience. But I can say a poorly designed setup will be a detriment more than a benefit. Front end jumping up, diving down, pulling to a side, etc.

The biggest issue I see with the 'DIY Universal' kit is the fact there is no track bar. I see nothing preventing side to side movement of the axle.

The 'issue' with the 3 link kit is related to design. You can end up with a LOT of squirrely behaviors if you don't have an 'expert'. I farmed my design to my OCD fab guy. He provided all the bracket mounting locations and explained the 'numbers' behind the locations as well as the proper way to do the track bar.

I would consider using the existing FJ80 radius arms you have and lengthen them 6-12" and use a quality heim. As much as I LOVE Ruffstuff, their heims wear fairly quick. My OCD fab guy recommends and uses FK brand joints in his link suspensions; pricey at $80ish for 1 1/4" ones. I would then try to match the track bar length to your steering drag link. Then fab a frame mount to make sure the track bar and drag link have the same angle.

I would still run a track bar on the DIY Radius Arm Kit kit. Setting up the 3 link and steering doesn't seem to be too bad from the stuff that I have read and watched. I'm not exactly sure how easy it would be to extend the current radius arms. If they are cast iron, or tempered in any way, extending those would be really difficult. I'm still leaning towards a 3-link, as long as I can get the geometry right. I'd want to replace the himes with Johnny Joints eventually, just because they can be rebuilt and greased.

 

[DangerNoodle]

So I think I have decided on a 3-link for the front. If I ever want to be able to run Coilovers without too much trouble, this is probably the easiest path. I'm looking at the Trail Gear 3-Link kit for Toyotas. (Trail-Link Three Front 3-Link Kit) It has Creeper Joints which look just like Johnny Joints, which would be the best. I'll have to get more tubing for the upper link, but so be it. Using a 3-Link calculator, I came up with this:

The anti-squat is about perfect, as long as I can get this setup to fit on the 40. Not being able to measure at all is really annoying. I wish I was back home and able to work on things. The Roll Axis angle seems to be really good for handling at speed, which will be good. To you link experts out there, how does this setup look? Are there any adjustments that I should make? As far as I have read, COG is not as important and hard to find, so it can't really be factored into the design. This also follows the 25% rule pretty closely, as the lower front link is 9 inches different from the upper front to back. (That is what it is supposed to be, right?) I'm not too sure about the Panhard, and the final locations/dimensions of it. Does anyone know what the Instant-Center X-Axis is? Is that something to really take into account?

I also ordered a set of adjustable coil buckets/shock mounts from Ballistic Fabrications. They had a 20% off today for Cyber Monday that was hard to pass up.

I am also looking at weld on beadlocks for the steelies that we have with the krawlers. (Big & Little Hole Weld on Beadlock) Has anyone had any experience with these? They look pretty straight forward to do.

That's all for now. Thanks in advance.