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Toyota Axle Swap
Axles have always been at the back of my mind
every since starting the buildup of my Samurai. I really wasn't too
worried when I ran my 30" tires or even my 32" tires as long as I kept
a light touch on the go pedal. Things changed when I bought the 33 x 15.50
Swampers. That little voice in my head started reminding me how small my
axles were and I think I drove with more apprehension than before. The
biggest problem was that with the bigger tires I could try bigger obstacles
which usually led to getting stuck in more difficult situations.
Things came to a head on our second exploration of the Lost World trail.
On second examination of the pictures of the spot where I broke a front axle, it
didn't look that hard, but the right combination of weight transfer and tire
wedging proved too much for the stock axle. So like everything in the
rockcrawling world, you build it, find the weak spot and then build it
stronger.
A lot of the information I am going to present
here comes from scouring the various message boards on the internet.
Toyota axle swaps have been done many times before so I am not breaking new
ground. Also these are not the only suitable axles for swapping under a
Zuk, certain year Wagoner's have full width Dana 44's with the proper offset
diff for the Zuk drive train. I won't go into hybrids or custom axles
because the sky is the limit there. Based on my reading here's some of the
reasons why I chose the Toyota axles:
1. Cost. You can pick
up 80-85 Toy axles for as low as $100 each. The later the year, the better
the front housing is gusseted from the factory.
2. Aftermarket
support. Limited slip, locker, ARB, or spools are readily available for
the 8" Toyota rear end as well as a wide selection of ring and pinion
ratios.
3. Removable third
member. Just like the Samurai. This makes it real easy to install
gears/lockers. Also the pinion flanges can easily be re-drilled to accept
the Samurai drive shaft hole pattern and vice versa.
4. Brakes use the same
threaded fittings, 10mm X 1.0. For the front, use Napa brake line #38688, approx
22-23" long with a female connector at each end, connect one to the Zuk
hard line, one to the Toyota caliper (if you already have extended brake lines
for your Suzuki, you don't need to buy new ones). For the rear the same
line can be used to go between the hard line on the frame and the hard line on
the axle.
5. Flat top knuckles.
With the stock knuckles you can easily make or buy a steering setup that puts
the tie rod and drag link above the springs. Note: If you want to
use a hi-steer setup you will have to move your steering box forward. A
standard crossover setup will allow you to keep your steering box in the stock
location.
6. While still being a lot
heavier than the stock Samurai axles, these axles do weigh less that the Dana
44's and the pumpkin is smaller.
7. Strong axles.
Based on data I have found on the internet ( one source here: http://performanceunlimited.com/illustrations/frontaxles.html),
the Toyota axles are 30 spline with the smallest diameter (weakest point) being
approx. 1.24". A front Dana 44 axle's smallest diameter is
1.128", most of them are also 30 spline. For the front the Dana 44
swap has an advantage because the Toyota front axle uses a birfield joint
(though much larger than the Samurai birfield). So if you want 38"+
tires the Dana 44 swap will be a better way to go in the long run. My goal
is 35" tires so I believe the Toyota axles will be perfect when combined
with the light weight of the Samurai.
8. Axle width. From what I
have read the Toyota axles are 5" wider than the stock Samurai axles.
How wide is good is a debate that will never end. In many cases wider is
better but in just as many cases your may be forced to take a very difficult
line because you cannot fit thru an opening. I am pretty happy with my
Zuks stance as it is so based on my calculations I will be 1.5" wider than
I am now using common 3.75: backspaced rims and the Toyota axles. Here's some
additional axle width information I found on the web:
Stock Toyota front axle measurements for comparison:
55.5" wide, 29" spring perch centers, '79-85 Toyota trucks and 4runners
63.5" wide, (set up for coil springs) 90-97 FJ80 and FZJ80 Landcruisers
'86-95 IFS front end is about 58.5" wide
'93-98 T100 IFS front end is about 65" wide
Toyota Rear Axle Widths:
55" wide, '79-85 trucks/4runners
58" wide, '86-95 trucks/4runners
60.75" wide, '95.5-up Tacomas/4runners
66.75" wide, '93-98 T100 trucks
The last thing I'll touch on is cost. While
this is a relatively easy swap, there are still a lot of costs that tend to add
up quicker than planned. I'll outline my costs below and update them as I
go. My target price for the swap was about $1500, I already see I will
exceed that. Here's the breakdown on what I have spent so far and remember
you can find better deals the longer you look, I have given myself a month to
complete the swap:
Front axles from an 85 Toyota - $250
ARB - $575
5.29 R&P - $180
R&P Install Kit - $125
Warn Hubs - $130
Rear axle from an 85 Toyota - $250
Spool - $200
5.29 R&P - $180
R&P Install Kit - $125
Diff Guards - $17 (8" Weld on Pipe Cap)
Hy-steer Steering Arms/Pitman Arm/Tie Rod/Drag
Link - $550
Misc bearings and oil seals - $60
Rotors/Brake Pads - $75
Brake Lines + Tools - $40
6 Lug Toyota Wheels w/ 3" backspacing - $281
Install of Gears & Lockers $299
Longer U-Bolts for Front $44
Stuff I was able to sell
Samurai axles, lockers and 4.62's - $700
Samurai Rims - $200
Trail Tough Crossover Steering - $175
Trail Tough Extended Slip Yoke - $60
Update
2-14-03 - Stuff I learned
It's been almost a year since I
installed my Toyota axles and there were a few things I learned along the way
that should be on the first page of this write up.
1. You need to outboard your front
springs to match the Toyota spring perch spacing. I was told you could
just bolt the front axle up, you can but it'll eat spring bushings pretty
quickly not to mention the springs get a slight outward bow in them.
2. You can't rotate the
front spring perches. I think part of the reason my turning radius is less
than desirable is my caster angles are messed up. The stock Toyota spring
eyes in front are nearly on the same plane with each other. Keep this in
mind when setting up your shackle/spring mounts. You really can't get good
caster with a shackle reverse like mine is setup and using a shackle that hangs
down even lower only makes it worse. The only solution is to cut and turn
the knuckles. The way mine is setup is useable, but the turning radius
could be better.
3. Shave your
differentials. Not only do you get a little more ground clearance but more
importantly you get rid of the drain plug which eventually gets ground down to
nothing. Here's a good link to some info
on how this is done or here.
4. 5.29 gears have held up
well.
5. Toyota axles under a Zuk
with a stock 1.3 and 117:1 crawl ratio are darn near bulletproof. I
initially ran 35" tires and then switched to 37" tires and the axles
have held up beautifully. If you do need more strength, longfields
are available to replace the stock birfield joint up front and chromoly
rear axles are also available for the rear.
I had never seen taken apart a Toyota axle before, much less
tried to pick one up. While a single person can pick up a Zuk axle, it
took 3 of us to get the front Toyota axle up on my workbench! It looked
like the oil seals where shot as the knuckles were fill with gear oil.
after stripping the axle down I took a few pictures comparing the stock Samurai
axles to the Toyota ones, I wasn't expecting as big a difference as what I
found.
The picture above shows a stock Samurai rear axle
next to the Toyota rear axles. Also the rear wheel bearings on the Toyota
axle look to be at least 50% bigger that the Samurai ones.

The biggest difference is in the front. The
first picture shows the 22 spline Samurai axle next to the 30 spline Toyota
axle. The second picture compares the two birfield joints, note the
Samurai unit of the left has a additional ring added to it for strength, so a
stock one is even smaller. You'll also noticed the Toyota birfield has a
pair of flats on it which allow it to fit into the knuckle when they are
oriented vertically.
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