Building a Zuk

Page 1


I have a lot of people e-mail with questions on where to start when building their Samurai.  My lift pages kind of show the experiments I have gone through building mine but they don't explain why I added the air locker, lowered the R&P, or how does the track bar work.  I am hoping this page can answer those questions and help those of you new to four wheeling decide on a course of action.  Like anything, there are trade offs to everything you do, there is no perfect setup. With that said here are my goals:

1. Keep it light (so no Dana 60's or 35" tires).

2. Keep the cost down.

3.  The Samurai will be a dedicated off road machine with the main emphasis on rock crawling. 

4.  Most important, I wanted to do as much as I could myself (that's half the fun).

If I were to start over, the following would be the order in which I would proceed.

The Lift

Suspension flex is needed to play in the rocks.

If you have been keeping up with my experiments you'll know I have gone through a lot of suspensions.  My Samurai was my first dedicated 4x4 so my only other experience with modified rigs was Jeeps.  Most Jeep owners put a lifted spring based lift kit on and call it good.  This works fine for the heavier Jeep, but on a lightweight Samurai, lifted springs cause a harsher ride due to their heavy arch.  That same arch that gives you lift also limits your flex.  In my opinion a spring over axle (SPOA) conversion  is the only true way to lift a Samurai (where that sort of suspension is allowed).  By moving the axles under the springs they exert much more leverage against the springs, causing them to flex better and ride better.  A SPOA setup is also a great jump off point for bigger and more flexible lifts.  Missing links and longer springs can easily be added to increase articulation.

Here's a cracked axle tube, right at the welds.

No, it's not broken, that's how it's supposed to look.

If I had to do it again I would skip the lifted springs and go with a spring over right away.  I am more than happy with my Rocky Road spring perches due to the fact they do not have to be welded to the axle tube, they weld to the stock spring perch.  If  you get a pad that has to be welded to the axle, at least add some supports between the new pad and the old pad.  For spring I would go with YJ springs in the back for sure, along with a missing link shackle.  The flex I am getting with this setup still amazes me.  I am happy with running the stock rear spring up front and if I had a tight budget I would do that again, since you already have the springs you just need some longer shackles (mine were $24.95 a pair).  If money is no object I would go YJ's all around.  The CSC shackle reversal setup for the front flexes a bit more than what I have, has near 90 degree approach angles and provides an even smoother ride.


5psi, notice how the tire squishes out?

Next comes tires.  Your best bet is to go on some runs with other people with similar vehicles and see what works in your region.  A tire that works great in the rocks may not work great in really sticky mud and vice versa.  Also keep in mind the weight of the Samurai when watching a tire work on a heavier vehicle.  If the tire doesn't flex much after being aired down on a heavier vehicle, it's certainly not going to flex well on a lightweight vehicle like a Samurai.  Based on what I saw here in Arizona I settled on a set of 32X11.50 BFG MT's on 15x8, 2" backspaced wheels.  The BFG's flex great (when aired down), have 3 ply sidewalls for protection from the rocks, and have a moderately aggressive tread that works well in dirt, rocks and Arizona mud.  I considered 33's, but decided against them after seeing how little upward axle travel you get with them.  Remember articulation is not just droop, but also how far you can stuff a tire up into the wheel well.  33's are just too big for the Samurai's wheel wells unless you run a body lift or cut the fenders.  

The rear axle next to a 32" tire, can you say small?

Big tires also add a lot of mass that needs to be moved by that puny 1.3l engine, keep that in mind.  Also look at the size of a Samurai axle above, if that makes you shudder skip the next part.

The weak point on the front axle, the birfield joint

The front doesn't get any better.  It is even smaller in diameter than the rear axle and has a birfield joint.  This is the weak link, turn the wheels hard, stuff the tire into the body and be prepared to bust one of these open.  I positioned the one above in the worst situation.  When you turn the tires hard one direction, one of the balls in the birfield joint is being held in by the thinnest part of the joint.  Typically the outer shell would crack right where the ball is.  Luckily you can just unlock the hub and 3 wheel out of there, or a trail fix would take about a half hour with practice (and as long as you have a spare). 

I hope I haven't scared you off.  You can successfully 4 wheel with these weak links, you will just have to develop a better driving style. Stay off the gas, if the tires start to slip, back off and try a different line.  In rock crawling, slow controlled motion is the name of the game.  Once in a while you may have to gas it, but do so only in an emergency.

 Lastly, since a wider track is a major benefit when rock crawling (for stability) I went with 2" backspaced wheels (stock is 3.75").  I may add some wheel spacers later to get an even wider track, but for now this combo works good. 

As of now, if I started over I would go with the same tire/wheel combo.  I have been thinking about getting set of 32" Swampers for use on the harder trails but I want to see how they flex (6 ply sidewalls) before I try them.


Everyone has passed a Samurai on the freeway at one time or another.  Odd are good that the Samurai driver had his foot to the floor.  Samurai's are utterly gutless in stock form, worse yet when you add bigger tires. The upside (yes, there is one) is the engine is small and light, keeping the overall vehicle weight down.  The small engine also keeps the tiny (some would say "cute") drive train components healthy. However, to be successful as a rock crawler, something has to be done to address this lack of power. The easiest way to address the power problems off-road is to go for lower gearing.  Start with the transfer case.  The stock crawl ratio is roughly 30:1 (using the numbers and calculations on A GRS I (4.16) gear set will drop the low range a whopping 84% (56:1), this makes an unbelievable difference and is more than adequate for 31" tires. An even lower transfer case gear set is available, the GRS II (4.89) gear set reduces the low range 115% (66:1) though at a much higher cost.  Both these gear sets reduce the high range a few percent, enough to help correct for the bigger tires, but nothing that will help you win any stoplight drags, but more importantly you will be amazed at the amount of control you will have off road, which is the primary purpose of this vehicle.

The other gearing option is a ring and pinion upgrade.  This swap will help your onroad performance much more than your off road performance.  I would suggest doing the transfer case gearing and when you add a locker (up next) do the ring and pinions at the same time. Your choice of ring and pinion will depend on what you chose for your transfer case.  If you went with a GRS I I would go with a 5.12ring and pinion set, this gives you a crawl ratio of 77:1, good enough for 33" tires or really good for 32" and under tires (I prefer to be under geared).  If you went with a GRS II I would go with a 4.62 ratio, this gives you a crawl ratio of 82:1, in my opinion perfect for 32's. There are lower ring and pinion ratios out there, but the lower you go the higher your rpm's will be on the highway.  So if a lot of highway driving is in order, the GRS II and 4.62's are better, 65mph would be 4100rpms with 32" tires vs. the GRS I and 5.12's at 4600 rpms. If you plan on trailering it, go 5.12's and GRS II.  Just remember your axles are still small so use the gas pedal sparingly while in low.

Lastly, you'll want to get some reinforced transfer case mounting arms.  Due to the added torque of the lower gears, the long arm is prone to getting twisted.  The best way to go is to get a mount that adds a flange to grab some of the bolt holes on the back of the transfer case like the one pictured above.  If you don't do this you will want to regularly check the bolts that hold the arms to the transfer case for proper tightness.  I had problems with mine working loose until I installed a mount like the one shown.  You will also want to carry a spare t-case mount bushing.  Not matter how careful you drive you will break one from time to time.  The alternative is to go to a solid mount that uses polyurethane spacers instead of the stock rubber spacers.  I currently run this and haven't found any downsides (these will not break unlike the rubber mounts, so it has moved the weak link somewhere else).  I was breaking one rubber mount every other run so it was getting expensive replacing them.

Since I don't drive my Samurai as a daily driver I would get a GRS I with 5.38's the second time around which computes out to a 81:1 crawl ratio.. You can almost get both of those upgrades for the price of a GRS II.  I just happened to luck out and bought my GRS II used which saved me nearly $500. 


If you have smaller tires, try driving up a 33" tire with no locker, or even one, it's not easy.

A locker is what really allows a 4x4 to be a 4x4.  What?  It's true, in stock form, any 4x4 with an open differential will spin a tire if one of them looses contact with the ground, rendering it a 4x2.  In rock crawling you will be lifting your tires constantly due to the uneven terrain and large obstacles. A locking differential locks both axles together so they will always turn (most lockers do ratchet in corners). Get a Lockright or similar unit for the rear.  I would put it in the rear differential because the rear axles are bigger than the front and the carrier is stronger, also when you climb (and you'll do a lot of it) most of the weight of the vehicle is transferred to the rear, so you will see more benefit to the locker in back as opposed to the front.  If there is no pressure on the tires, the locker isn't going to help that much. 

When you can afford it get another locker for the front.  Adding the second locker will take an enormous amount of stress off the axles due to the ability to easily climb tall obstacles without the back axles needing to push the vehicle up it by themselves.  The picture above is a good test that illustrates this.  When you try and drive up an obstacle taller than your tire with just a rear locker, your front tire will get pushed into the obstacle, making the rear drive train really  have to work to overcome this situation (also a common time to break a rear axle), with two lockers you will go right up as if the obstacle weren't there. 

The downside to the front locker is it will make steering hard, if not impossible at times when in 4 wheel drive low range.  For this reason I spent the extra money and installed an ARB locker in front, it is an air actuated locker, so at the touch of a button I can engage it and disengage it.  It works great off road, the ability to turn it off, adjust the steering and then turn it back on is worth the price of admission. 

If you plan on serious rock crawling you'll need both lockers, for light four wheeling a rear locker will suffice. Would I do it the same?  Yes.  The Samurai motor generates so little torque in 2 wheel drive that the rear locker is almost transparent onroad.  It will pull a little time to time and make the usual clicking noises while turning around, but there is very little bucking or tire screeching. I would definitely get another air locker for the front.  It was expensive but it is really handy to leave it off until it is absolutely needed.  Another benefit is you can use the air compressor that drives the locker to air your tires up after the run or even re-seat tire beads (with the use of a ratchet strap snuggly around the tire).

Update 6-18-01 After watching first hand how a Zuk with only a front and only a rear locker handled the same trail I'd say put your fist locker in the front, the extra pull up front really seems to help in climbing situations.

Spare Parts & Tools

At this point you'll be pretty well setup and will be hitting some hard trails.  Start stockpiling spare parts.  You don't need to get these all at once but gradually work at filling this list.  This is all stuff that if it breaks you may not be able to drive it out, or they just break regularly.

Hi-Lift Jack.  Get one, it has a million uses.  But also carry the stock jack or a bottle jack, when you get a really flexy suspension you will find it hard to jack up the axles by using a Hi-Lift on the bumpers.

Welding with two car batteries.  Use only as a last resort.

Carry a common set of metric tools such as wrenches, a wire cutter, pliers, hammer, file, etc.  Some of the more uncommon stuff I recommend carrying are a small folding shovel, pitman arm puller and pickle fork.  Also, if you can weld carry 2 sets of jumper cables, a welding helmet and some 1/16 dia welding rod in a waterproof container.

Other handy items I have seen a need for . a short section of chain with a way to tie the links together (used to straighten a bent tie rod, or hold something together).  A tow strap, a good ratchet strap (can be used to re-seat a bead on a tire) and zip ties, lots of em.

Fluids.  Carry extra oil, water, gear oil power steering fluid (if you have it) and brake fluid.

Aftermarket Rag Joint - Pep Boys #31002 (in the red "Help!" packages).  Carry one always.  You will rip these once you start rock crawling.  This is the little piece of rubber that goes between your steering shaft and steering box.  You can drive home on a ripped one but you will be all over the road due to the slop in the steering.  I have a hard time keeping my spare in my toolbox, I am usually loaning it to someone on the trail.

Rubber transfer case mount - Suzuki #2961082C01.  Same here, you'll pop these from time to time and you don't want to drive around too much with a broken one.  In a pinch a bolt, nut and a bunch of washers can be used to hold the t-case from moving around too much.

Clutch cable - Suzuki #2371083024.  I have seen a battery short out from hitting the hood, sending all that current through the clutch cable, utterly melting it.  These typically start breaking at the firewall so they are easy to check before you head out.  Look for a cracked outer sleeve.  These are a little expensive so maybe replace your old one at some point and use it for a spare.  Also, stick with the factory unit, the aftermarket ones have a plastic mount (stock uses a metal mount) at the firewall and tend to break sooner than the stock unit.

U-joints, carry at least one, or see below on spare drive shafts.

Carry a spare fuel pump (if carbureted).  Or a good idea is to unhook the stock mechanical unit and plug the holes, then switch over to an electric, leaving your stock pump in there as a backup.  After your first tune-up, keep the old cap, rotor, plug wires and plugs as spares.  Also when you replace the stock coil (mine idled better afterwards), keep the stock unit as a spare.  I also carry a spare fuel filter and a container of radiator stop leak and an assortment of nuts and bolts of various sizes.

Since your choice in steering could vary greatly you'll have to decide what you would need on hand if something happened to one of the linkages.  Since I have a custom hi-steer system, I carry my stock tie rod and a spare ball joint as spares.  If your stock or running a z-link you may want to carry a stock drag link and tie rod.  Optional would be a pitman arm, if you have one handy, toss it in the tool box (my spare came in handy after a roll over).

Lastly if you really want to be prepared carry a front and rear drive shaft.  This way if you break the shaft or a u-joint you can just undo 4 bolts and put a replacement in quickly.  Changing u-joints on a Samurai is not easy with the right tools, in the field it is downright challenging. 

Ok, so your saying "Where the heck do you put it all?".  I am still working on that one.  FWIW I have the spare drive shafts and shovel strapped to the inside of the rear tailgate.  The spare tie rod is bungeed to the Hi-Lift jack (jack is mounted behind the seats).  I recently added a decent sized ammo container to the bed of my Zuk, check out the Tips page for more info on that and how to secure it.  Lastly I placed my welding rod in a section of radiator hose and taped off both ends (so now I have a spare section of radiator hose).

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