Well, after a year on Phase II, I
found that I had pushed the stock suspension to its limits. In front,
the shocks were limiting droop and with the repeated strain, one lower
shock mount actually tore right off the axle (in fact, you may want
to inspect your factory shock mounts, the weld quality on mine was poor
and there was rust working its way under the weld). I was also not
really happy with the relocated holes in the front spring perches
(especially with the aluminum axle shims
- center hole was in the thin end). In back, the shocks limited
compression in their stock location.
So, instead of simply welding the broken shock mount back on, I decided
to just cut everything off and start out clean. I took this opportunity
to rebuild the front axle (it was leaking gear oil
badly due to an improperly positioned MarTack), and after
removing the broken right shock mount, decided the left one had to go
as well, and while the grinder was out, I cut off those silly sway bar
end link brackets and that useless torque rod bracket.
So, I put the rear springs back to the original NWOR setup (temporarily
- in order to free up my stock rear leaves) and then acquired a rear
spring pack from an '83 short bed pickup (thanks to Barney McNamara for
that). The pickup springs had about 3" extra free arch than my
4Runner springs (8" vs. 5"), so I made use of the three main
p/u leaves, then the 3rd and 4th leaves from my stock 4Runner pack then
initially I used the 4th (1st overload) leaf from the p/u pack. Later I
took the 2nd 4Runner leaf, cut off the mil-wrap end, cut it in two at
the center hole, making two leaves out of it, drilling new center holes
in each half to match the other leaves. I ended up with a nice 7-leaf
pack, all fairly thin and very flexible. After measuring, I found that
using symmetrical springs in front resulted in a fairly level body. No
need to fool with the left and right spring nonsense, aside
from welding a 3/8" piece of flat stock to the driver's side perch
to reinforce it and raise it level with the passenger side perch.
Below, you can see a side-by-side comparison of the main leaf from an
'83 Toyota pickup rear spring pack and the same leaf from an '85
4Runner. The early model springs used the small eyes on both ends but
more importantly had nearly 3" more free arch than the 4Runner
leaves. I'm not sure if this was a pickup vs. 4Runner difference, an
'83 vs. 85 difference, but whatever the reason, I prefer the '83 rear
spring pack, at least the upper 3 leaves, anyway.
To finish up the design and correct the problem of the springs hitting
the pitman arm on the steering box, I went with a dropped
front spring hanger (2.5" drop from stock) and went to 3.5" longer than stock
front shackles to correct the caster angle for steering. Bump
stops have been changed a little and I'm still working on getting them
set to my satisfaction.
So what did all this work get me, lift-wise? When I first measured the
front wheels wells on my nearly stock 4Runner, I got 36" running
on 30" tires. Now, after a 3" body lift and 33" tires
(1.5" lift at the axle) I get a 44" fender height, a
difference of 8" from stock. Subtracting the 3" body lift and
1.5" due to the taller tires and I see 3.5" of lift from the
suspension. However, most of that is due to the longer shackle
(3.5") and dropped spring hanger (2.5"), which average to
3" of static lift. So, subtracting that 3" leaves 1/2"
of spring lift! Not surprised, the spring pack is nearly flat. I may
ultimately add a 7th load leaf to the pack for a bit of lift.
A major limiting factor in the Toyota front axle suspension is the
shock absorber. With a conventional shock mount, there is an upper and
lower mounting point that are fixed. At full compression, the shock
should be short enough not to bottom out (bottoming out is bad)
and at full droop, the shock should be long enough to not limit droop (limiting
droop is bad) since either case imposes high loads on the shock and
mounts, neither of which are designed for that purpose (case in point
my torn off shock mount). The length of the tube of the shock is what
limits compression, so ideally it should be short. The length of the
rod in the shock is what limits extension, so ideally it should be
long. However, in compression, the rod must go somewhere and that is
into the tube. So, if you add an inch to the length of the rod (for
extra extension) you must also add an inch to the tube, thereby
limiting droop. In fact, for every inch you extend the rod (and tube)
you loose an inch of compression, but gain 2" of extension
(1" of tube plus 1" of rod = 2").
So it seems so simple, make a really long tube shock and mount it up
high enough to allow the springs to fully compress. However, there is a
wheel well located above the frame. One option is to cut a hole and run
the shock up and into the engine compartment. FIne if you have room,
but with EFI, power steering, on-board air and welder, I have no place
to go up, plus I like the idea of keeping the engine compartment
reasonably isolated from the dust and mud thrown up from the tires. So,
if a single long shock is out of the question, how about folding one in
two to create a moveable shock mount?
I saw a really trick looking long-travel triple shock concept
from James Stevenson. He uses this in race trucks that have rules
preventing body alterations for things like long shocks. So, I modified
the design for my front axle to prevent the shocks from limiting
travel. In addition it allows for re-centering the shock on the axle
that now lives 2" (and later 2.75") ahead of it's stock
location. The shock mount plate is fully bolted on to avoid welding on
this critical part of the frame. The base plate serves as an enlarged
and relocated contact area for the bumpstop attached to the top-mounted
spring u-bolt plate. Finally, the two through-bolts that hold it to the
frame serve as handy ground points for my dual battery wiring (1/0
cable lugs need solid anchor bolts) and also hold my motor mount
retaining chains to the frame. The two short shocks on the sides are
Rancho 9120's, approx. 10" compressed length and 14" extended
length and approx. 4.68" travel. In the newer Rancho 9000XL part
numbers, that equates to a 99120 shock.
I later swapped the Rancho 9010s
(pictured above) for some l-o-n-g Rancho
9012s shocks which provide adequate travel when mounted to the pair
of 9120s. This nets me about
18.5" of vertical front shock travel (13.97 + 4.68 = 18.65"),
which should last me for a while :-) I hope to have an inch or two of
unused travel at the top and bottom. With the 2.5" spring hanger
drop, I've increase my down-travel nearly 2" and should still have
the same up-travel. Also, in changing from a 1" to a 3" body
lift, I was able to raise the lower end of the auxiliary shocks by
2" and pushed them in closer to the frame to boot. The whole idea
of this design is to eliminate any shock limits of both up and down
travel. Another side benefit of this design is that it eliminates the
excessive leverage on the frame caused by a rigid "longer than
stock" shock mount. This is an important consideration and is part
of the design concept.
Here's a closeup of the upper mount. The basic idea with this design is
that the upper shock mount floats up and down. An added benefit is that
the main shock loads are transferred directly to the frame and there
are not the heavy twisting forces you get with a tall shock tower. The
tops of the three shocks are connected with a piece of 3/4"
hardened steel rod, currently with hitch pins on the end to hold
everything in place. I also remounted the main shock with the can down
(rather than up) to keep the adjustment knob out of harms way. Later I
converted the manual adjuster over to the air-operated remote control
system and am really happy with that. The auxiliary shocks are left at
the lowest setting all the time.
After many years of use with the above setup and a few minor
modifications to the design (that probably weakened it) I had problems
with the upper u-bolt clamp brackets fatiguing and breaking. That was
the one part of the design I was not totally happy with. So prompted by
the breakage, I decided to "do it right" this time. I totally
abandoned the stock shock bracket for support and instead made a
one-piece shock tower to support everything:
As you can see above, the new tower is all one piece and it wraps
around under the frame (provides an enlarged bump stop pad) both bolts
through the frame (two bolt holes in the center) and to the outside
face of the frame (two bolt holes inside each tower). Now the auxiliary
shocks are held in-line with the main shock which eliminates any side
loading. Also with the massive side brackets on each tower, there is no
flexing or give as the shocks cycle up and down. And there is little
leverage on the frame, so no additional frame bracing is required as
would be common with a single tall shock tower.
One modification that also has been working very well over the years is
switching the top shock mount rod to a 3/4" high strength alloy
steel and also adding steel tubes for inter-shock bushing spacers with
compression bolts on the end have allowed the upper shock mounts to be
nice and snug as well. This eliminated any slop in the bushings and the
alloy steel rod and spacers have not bent in the slightest in many
years of hard use.
Latest upgrade has been to swap out the 10+ year old Rancho 9012s for a
set of the new 9012XL gas charged shocks from Rancho. Much softer ride
and still fully adjustable. The shock body is somewhat larger than the
old 9012s, but it fits fine in between the two 9120s. One side effect
of the gas chaged shock is that the gas pressure forces the two side
shocks to fully extend at rest instead of the normal fully retracted
position.I think this works quite well, as I now have nearly 4" of
uptravel on the new 9012XL shock that is nice and smooth, where before
I only had less than an inch before the 9012 shock fully compressed
then extended the dual 9120s, which were of course twice the stiffness
of the single 9012. So as a result, the middle shock travel is used
from the bumpstop down the first 12" of travel, then the side
shocks start to compress for any remaining travel, where before it was
the side shocks for the first 4" and the middle shock for the rest.
A shock tower kit, built to handle 0" - 3" of body lift is
available for custom orders. Cost of the shock tower and mounting
hardware is US$225.00 + tax and shipping (shipping cost in the US runs approx. $30-40 depending on destination). Shocks are not included, you
will need a total of 4 Rancho 9120 or equivalent for the side shocks.
Then two more shocks of suitable length for the center. Upper shock
bushings may need to be modified to 3/4" ID, this is easily done
with a die grinder.
Here's a closeup of the lower mount, which I welded to the flipped
u-bolt plate. This allowed me to position it 2" behind the axle
center. If I had not moved the axle forward, I could have used the
stock shock mounting bracket. In order to gain some additional
clearance at the front of the springs, I had to also drop the front
spring hangers 2.5" and also I moved them 0.75" forward,
resulting in an overall 2.75" forward front axle location from
So, how does this setup work? In a word, FANTASTIC!
Articulation is the key, one side of the axle goes up, the other side
goes down. On the left, I've backed up a boulder to twist up the front
end. In the middle shot, you can see the main shock has bottomed out,
and the auxiliary shocks have lifted about 2". I was running a
spacer under my bumpstop in the photo, but since the clearance looks
good, I'll be removing it for more up-travel. In the shot on the right,
the auxiliary shocks are fully compressed and the main shock is
extending. I think I measured around 24" of articulation at the
rim in this shot. Once the main shock bottoms out, the auxiliary shocks
lift, providing an additional 4.5" of up-travel. In effect it is
like having a very tall shock tower, but without the leverage and
stresses that a very tall shock mount can cause.
Since I was no longer using the stock shock mounts (or sway bar or
torque rod), I decided to cut off all that excess steel while I had the
axle torn down. The passenger shock mount had already torn itself off.
Cutting wheels and a air hammer with cutting chisel took off the bulk
of the bracketry and an electric grinder smoothed off the remainder.
Here's a look at my bolt-on lower shock mount. I serves a few functions
beyond the attachment point for the auxiliary shocks. Firstly, it
widens the bump stop pad on the frame to give a bigger target for the
bump stop to hit, since my axle is relocated. Also, the 7/16"
bolts that attach it to the frame made for handy frame ground studs for
my dual battery setup. Its fabricated from a pieces of 2x2-1/8"
angle and some 2x1/8" flat bar with some sections of 3/4"
square tubing for stiffening. Making this bracket a bolt-on gave me two
Here's a closeup of the auxiliary shock saddle clamp. I found a
2-1/4" muffler clamp was a perfect fit for the Rancho shock tubes.
The two clamps are welded to a piece of 1x1-1/8" angle and two
tabs below allow the assembly to be bolted to the cut off stock shock
tower. I used some rubber sheeting to isolate the shock tube from the
metal of the clamp. The purpose of this component is to keep the
auxiliary shocks from "flopping" around and also to
"aim" them out enough to allow full up-travel under the
Here's the finished product in compression. Gotta love that
clearance at the rear fender, now have room for 35's no problem. I did
have to install longer s/s brake lines and get my drive shaft slip yoke
modified for extra travel and I also had to fabricate some 2"
longer spring shackles to handle the extra length. The entire project
was done as a bolt-on, only had to cut off the top of the factory shock
mount. If interested, I can custom build all the shock mounts for this
setup, including a front u-bolt flip kit so you can bolt up the same
setup. You'll need a solid front axle with crossover steering to do this
One important thing to remember if you do this sort of shock setup is
that once you remove your shocks as suspension limiting devices, you
better be sure the rest of the system is up to the increased travel. In
my case, the s/s brake lines were too short, I had to get longer ones
and I had to relocate the end of the hardlines down onto the side of
the frame. Also, the travel of the front drive shaft slip yoke was
inadequate and I needed to have a long travel unit fabricated.
One other limitation of the stock Toyota front suspension is the way
the rear shackle mount it let into the frame. Since the frame tubes are
angled inwards at approx. 12° at the very location the rear
shackle mount is located, there is a tube inserted through the frame to
support the shackle. For clearance, the tube is approx. 1.5" wider
than the eye of the spring, so in the stock design, the shackle sides
are bent inwards to make up this difference. This can lead to problems
in that if the shackle folds back too far, it can make contact with the
frame, causing the suspension to bind up. I had this problem with the
stock shackle and my NWOR 3.5" lift springs, then I used a longer
Downey Rubicon (3" longer, cut down to 1.5" longer) shackle
to fix that. But with the 2" longer pickup springs, this problem
had returned. I contemplated getting another set of Downey shackles,
but decided there must be an easier way. Another option I've seen used
it to place a spring hanger below the frame, similar to the way the
rear springs are mounted. This is popular with the solid-axle-swap
folks, since they have no stock mount and this is easier to install
So, instead of the complex bent shackle, I adopted the "wide
body" shackle design I had seen used elsewhere for use on my
truck. I measured the width of the upper and lower ends of the shackle,
divided the difference between the two in half and found that to be
approx. 3/4". I found some black steel pipe fittings that were
about that same size, reamed them to fit over my 18mm spring pivot
bolts, TIG welded them to some 3/8 x 2" steel flat bar, and then
TIG welded a large flat washer to the bushing to provide a flat surface
for the spring bushing to slide on. The flat bar was cut 2" over
stock length (i.e. 5.5" center-center vs. 3.5" stock). Then,
to prevent the spring bolts from pivoting in the shackle plates
(avoiding metal-on-metal wear) I fashioned some aluminum clamps to
prevent the bolt heads from turning, yet still allowing them to be
removed for service. I may ultimately drill them for grease fittings.
Anyway, I've been happy with this shackle. The longer shackle mounted
within the frame is very strong and I get the added droop the longer
shackle allows without the added height a lowered shackle mount would
I later replaced the +2" shackles
for +3.5" longer than stock (7" center to center). This
was done for a few reasons, one was to get back some positive caster
angle after installing the 2.5" front spring hanger drop. A second
reason was to add a brace to the shackles for a bit more stability with
the added length. The combination of shackle 1" longer than the
spring hanger drop and the brace gave me rock solid steering.
Interestingly, I got no added ride height with the 1.5" shackle
length change. If interested in making your own shackles, I also offer steel shackle spacers
(essentially 0.700" thick washers) that can be used to space out
the lower ends of the shackle plates at the spring eye to allow a
straight sided shackle to be used.
With all the work done to the front suspension, including flipping the
spring plates and u-bolts, moving the axle forward, etc. the stock
bumpstops would not be useable. My shock bracket was designed in part
to extend the factory bump stop plate on the bottom of the frame to at
least allow a chance of a bump stop on the axle to hit it. It is both
longer and wider than stock.
To mount the bump stops, I welded a piece of 2x2 square tubing to the
middle of the spring plate. A 3/4" hole was drilled in the bottom
for the center bolt and a 3/8" hole in the top for a bolt to be
used to attach the bump stop. I used to use a hollow rectangular bumpstop
but found it too bulky and soft. So, I switched to a 2" OD solid
round polyurethane bumpstop. To allow for adjustability, I machined a
2" round aluminum spacer with the center drilled and tapped to
accept the stud from the bumpstop and the bolt from the mounting
bracket below. By changing out the spacers, I can fine tune the
compression point to keep parts from hitting and still allow for
maximum spring travel.
So, now that the front end was working to my satisfaction (ha!) it was
time to look to the rear end. It was interesting running the the
Rubicon with awesome front axle articulation and non-existent rear axle
travel. The relatively stiff rear end would force the front axle to its
limits over obstacles. With the front limited slip differential, it
actually was beneficial in some respects as the front tires were forced
into contact with the ground. However, this was only a temporary
Toyota pickups up through 1983, used to run their rear shocks angled in
towards the center of the frame. However, in 1984, they changed the
shocks to run forward on the driver's side and back on the passenger
side. They also changed the orientation of the shock mounting bolts to
be parallel to the axle instead of perpendicular to it. Both these
changes severly limit the ability of the shocks to handle extreme
articulation off-road, both due to the relatively short length of shock
that can fit the stock mounting points and the fact that the shock eye
bushings bind up on the mounting bolts. I wanted to fix both these
problems at the same time, so I designed a shock mount that placed the
bolts perpendicular to the axle which allows the bushings to pivot on
the bolt instead of bind up, and also incorporated an angle shock
mounting scheme to allow a longer bodied shock to be installed.
One benefit of angling the shocks inward is that this allows for
increased vertical travel for a given length of shock. If a shock is
mounted vertically, it needs 1" of travel for each inch of wheel
travel. But angled inwards, at say 45°, the shock travel is
reduced by 30-40% over a vertical setup. With the 14" travel
shocks I selected, I am able to achieve over 19" of vertical wheel
travel (assuming my springs would allow that). A drawback to this
arrangement is that the effectiveness of the shocks is reduced by the
same amount the travel is increased. Since I chose an adjustable shock,
I can compensate for this by "cranking up" the rear shocks
for added stiffness if needed, more on this below...
When mounting a shock absorber at an angle other than vertical, several
things occur simultaneously that affect the shock's damping properties.
The first effect is due to the static angle. When a shock is vertical,
you get 100% of the shock's damping action acting to control the
suspenion's up-down movement. When you start tipping the shock over at
an angle, the vertical damping effectiveness falls off in relation to
the sine of the angle the shock is angled at (assuming 90 degrees is a
vertical orientation). Looking at some common angles and their sine, we
So, what the above numbers tell you is that if you angle the shocks in
at say 45 degrees, they are only 71% as effective in damping vertical
motion as they were if mounted vertically. That is, if the shock
generated 100 lbs. of damping force at a given velocity, only 71 of
those pounds would be directed upward to resist the suspension motion.
An equal amount would be directed horizontally (i.e. pushing against
the frame sideways) and that force would not do anything productive.
This is a static factor affecting the shock absorber effectiveness.
Note that this would also apply to say a coil spring mounted at an
angle as well. The more it is angled over, the less force it can apply
However, that is not the whole story. When you mount the shock at an
angle, it changes length at a slower speed, for a given vertical
motion, than if a shock is mounted vertically. If you look at the
extremes, at 90 degrees there is a 1:1 relationship of the suspension
moving up and down and the shock compressing/extending. If you were to
lay the shock on it's side (i.e. 0 degrees), the shock would not move
in and out at all as the suspension moved up and down. Once again, the
relationship of the shock's velocity relative to the suspension's
up-down velocity is related to the same sine function as above. When
the shock is vertical (90 degrees), the ratio is 1.00, when the shock
is at 45 degrees, the velocity is approx. 71% that of the suspenion's
So what does velocity have to do with anything? Well, a shock absorber,
assuming a common hydraulic design as is commonly used in vehicles
today, is a device that generates a damping force that is proportional
to it's speed or velocity. Ignoring friction effects (like the seals
inside the shock) and spring effects (such as from internal gas
pressure) and variable damping rates (as from progressive shocks), if
you compress a shock twice as fast, it generates twice the damping
force. Likewise, compress (or extend) it half as fast and it generates
half the force. OK, so where does this take us?
With the shock at an angle, it moves slower, relative to the
suspension's up-down motion, and the more it is angled over, the slower
it moves. Thus, if the shock compresses or extends slower, it is
creating less damping force for a given suspension speed. So this is a
dynamic factor affecting shock absorber performance.
Going back to the first part of this discussion, you need to combine
the static and dynamic effects of the shock's mounting angle to
estimate the overall effectivenss. Since both effects are independent,
their combined effect can be calculated by multiplying the factors,
which in effect squares the values in the above table
So we can see from the above table, that the shock effectiveness falls
off much faster than could be accounted for strictly by the static
effects of the mounting angle. And if you look at going from say 45
degrees (0.50) to 60 degrees (0.75) the shocks would feel 50% stiffer
at 60 degrees vs. at 45 degrees (0.75/0.50 = 1.50). And going from 90
degrees to 45 degrees, the shocks would feel 1/2 as stiff. The above is
a long-winded way of saying that as the angle of the shock decreases,
it pushes less hard less efficiently in the vertical direction.
So, what is the take away from all this? Mount the shocks as close to
vertical as possible for maximum damping effectiveness. However, you
need to temper that requirement with physically fitting a given shock
into a given space. Afterall, the axle is only so wide and that limits
how far apart the shocks can be placed. You only have a given amount of
vertical space between the axle and the frame (or upper shock mount) so
that affects how much vertical separation you have between mounting
points. If the vehicle is being set up for off-road use, you probably
don't want to have the shocks hanging down below the axle (rock
anchors). And, unless you are planning to cut holes in the bed and run
the shocks up through the floor (in which case you have unlimited room
and can do whatever you want, shock length-wise), there is not a lot to
do to increase this vertical separation.
So why not just use a short enough shock to fit in the space given?
Shock travel is usually the answer. You want to have a shock that can
extend far enough to not limit the suspenion's travel off-road.
Afterall, you probably just laid out a bunch of money and/or time
putting on the flexiest springs you could afford, so why have the
shocks limit what those springs can do? OK, so put in a longer shock.
Well, if the shock is too long, it can limit the compression of the
suspension (not to mention damage the shock), so that is no good
either. To get more travel out of a shock, it needs to have a longer
rod. In order to allow the longer rod to fit into the shock body, the
body itself needs to be longer as well. This is a dirty little secret
of shocks, that in order to get 1" more travel, the shock's
compressed length also increases by 1", and this is on top of
approx. 5" of non-useable compressed length in a typical shock. So
a 5" travel shock is about 10" long (compressed) and a
10" travel shock is about 15" long (compressed) and so on.
If you only have so many inches of vertical space to mount the shock
and you need a certain amount of vertical shock travel to accomodate
the suspension articulation, you have to work the numbers to find out
what works. If you can find a shock that is short enough to fit the
space and that also has the required travel, you are golden. Put them
in vertically and call it good. However, if you have a relatively low
lift that flexes quite well, you may find that in order to get the
shock travel you need, the shock's compressed length is too long to
fit. So this is when you resort to angling the top of the shock away
from vertical. How far to go? Ideally, find the angle that is just
enough to allow the shock body to fit with the suspension fully
compressed (this way the suspension bottoms out before the shock does).
Then make sure the fully extended shock is long enough to allow for
full suspension doorp/articulation. Luckily this part usually
"just works out", because as the shock is angled over, the
effective extension length is increased since the diagonal distance
increases less than the vertical length does. So, what you lose in
damping, you make up for in length.
OK, back to the shocks, in back, custom shock mounts allow long travel Rancho 9012 to fit without limiting up
or down travel. A u-bolt flip and custom lower shock mounts eliminate
welding the mounts to the axle. Above, a shock mount on the round cross
member allows room for the longer body shocks plus angles them over for
increased travel. The mount is a 14" length of 2.5x2.5x1/4"
angle with a piece of 2x1/4" flat bar welded (to form a
"U") that wraps around the round crossmember. A pair of
5/8" bolts welded to the angle function as shock pins and a pair
of 7/16" bolts go through the angle and round tube to hold it all
in place. I sized and shimmed the bolts so that the nut just bottoms
out on the threaded portion of the bolt, so as not to crush the round
So, while the design may seem like a bit of a kludge, it was carefully
thought out. I bolted it to the crossmember because it is darn tight up
there and this way it is easily removed if I want to modify it. The
bolts actually don't do a whole heck of a lot. Since they are vertical,
they only serve to resist the torque applied to the mount from the
shocks mounted out from the center. Also, vertical is about the only
direction you can drill a hole up there without dropping the gas
tank.The bracket contacts the top and bottom of the crossmember tube
and helps distribute the shock load over the full 14" length of
the bracket. I ultimately welded the bracket to the round crossmember.
It loosened up a bit and was causing some noise. Once I settled on the
final shock stud locations, I welded on another 1/2" threaded stud
for a future limiting strap attachment then bolted and welded the
bracket into its final location.
Upper Bracket --- Lower Bracket
I fabricated the lower mount out of a piece of 3/8x2" flat bar and
welded some 3/16x1.5" flat bar underneath for the double shear
shock mount. The 3/8" bar is drilled for the spring center bolt
and sits on the bottom of the spring pack. I may ultimately weld this
bar to the spring perch. The bolts are aligned perpendicular to the
axle to allow maximum articulation. The shock mounting position is
about at the axle centerline, high enough to be out of harm's way, but
low enough to accommodate the long 9012 shock body. I'll be installing
4-1/2" tall bumpstops directly to the frame rail to limit
compression to this length.
Above is a shot of the lower end of the shock and also visible is the
1" spacer I installed on the e-brake cable attachment point to
allow more down travel. It's just a 1" piece of 3/4" aluminum
tubing and a longer bolt.
While the above setup worked OK for about 3 years, one day I noticed
that the round crossmember had cracked and bent. I guess the thinwall
tube was just not up to the prolonged load from the shocks and
fatigued. So I cut out the center section with my upper mounts,
straightened out the remainder of the tube (since it supports the gas
tank and muffler on each end) and went about making a better upper
mount. I had a few goals in mind, one was to have the crossmember bolt
in place, so I could remove and modify it if needed. Secondly, I wanted
multiple upper shock mount locations to allow for fine tuning the shock
angles and thridly, I wanted to be able to run dual shocks in back.
Finally I wanted to place the top of the shocks as high as possible to
take full advantage of my body lift.
So I used a length of 3" channel cut and notched to span the space
above the frame rails. I found that at the angle the shocks were at,
that a 3.5" center-center spacing was the closest you could place
the shocks and not have them hit each other. So, I divided that number
in half and placed a series of 6 mounts along each half of the
crossmemver, spaced at 1.75" centers. The two center mounts are
3.5" apart. The mounts themselves are 5/8" grade 8 nuts
welded to the face of the crossmember which has a 5/8" hole
drilled and tapped for the bolts as well. End places are welded to the
ends and then a mounting bracket uses 3 bolts to attach the plate to
the frame and the flate to the crossmember. With the 3 flat head allen
bolts countersunk into the plate and screwed into 3/8" holes
tapped into the frame, the fit is very snug, no play at all and very
solid. Plus it comes out in about 5 minutes.
I currently have the rear shocks angled in about 29 degrees from
vertical and is seems to be working fine. This is all temporary until I
get the rear axle swapped out, new springs and shackles installed and
then I'll make the final setup w/ dual shocks.
Now with the new rear axle in, I was able to weld some new lower shock
mounts on to the axle to allow for a slightly longer shock to fit in
there. I was able to fit a 34" Rancho 9000XL remote reservoir
shock in place of the old 10+ year olr 9012s:
I also pushed the top shock mount all the way to the outer most upper
mounting bolt hole and this gives a much more vertical shock position.
The above photo was taken at one hole in towards the center. These
shocks still have the air operated remote damping adjustment as the old
9012s, so that is why I went with them. Ride is much smoother with the
newer shock technology.
BTW: The new rear axle is basically a wider IFS rear axle (3"
wider than stock), that has been shaved,
has had shock mounts and sway bar brackets welded on, with a Front
Range full floater axle kit installed inside with the Supra rear disc
brake caliper (integral parking brake). Finally it has provisions for a
rear traction bar integrated in with a center support for a future
center air bag for helping with carrying heavy camping gear. More on
that as it develops.
One of the main limitations of the stock springs on my 4Runner was
there length, 47". With a short spring, the only way to get lift
is lots of arch. Doing that makes the spring very stiff. One solution
is to run a longer spring which is much softer for the same amount of
arch and lift. Ultimately, I installed some custom 56" Alcan springs to replace the
stock 47" long ones to really make full use of the shock travel I
now have, which should be about 17" vertical. Below, is a shot of
the rear with the Alcan springs installed:
To mount the Alcan springs, I ordered new rear spring hangers from
Toyota. Since the Alcans require moving the front hanger forward about
6.5", placing them lower on the frame, I opted for the later model
'91 pickup hanger. Unlike the earlier model hanger, the '91 design is
longer and tapered in front. This should help make a smoother
transition for climbing over obstacles and the extra length should make
for a stronger mount. The Toyota p/n for the '91 mounts are: 48414-35120
and 48415-35050 (for the left and right brackets).
I ordered the '89 and later Alcan spring design, which means the rear
part of the spring is 4" longer than stock. This is in addition to
the 5" longer front half. This results in a spring with approx.
27" from the front hanger to the center pin and 29" from the
center pin to the shackle. Springs were ordered for a 6" total
lift, including 2" due to the lowered spring hanger position. I
ordered the springs directly from Alcan, it took approx. 2 weeks for
them to be built-to-order and another week to arrive via UPS:
The springs arrived about 3 weeks after ordering them; cost $400 plus
$55 shipping (~'00 pricing). So, with springs in hand, I preceded to
figure out where to mount them. In picture (1) below, you can see the
old NWOR 3-1/2" lift spring and the new Alcan 4" lift spring
side by side. The center bolts are lined up and the forward bushings
are to the right. NWOR uses 4 flatter, thicker leaves, while Alcan uses
8 longer thinner leaves (plus an anti-wrap half-leaf on top).
On paper, I determined that the stock axle location would be achieved
my moving the front hanger 6.5" forward. How did I determine that?
Simple, I used the front half length of the old springs (20.5")
and the front half length of the new srings (27") and took the
difference. THis ensures that when you move the center of the new
spring hanger that much farther forward than the existing hanger
center, then when the springs are fully compressed (i.e. flat) the axle
(and wheels) will be in the same location with respect to the body as
they were before (i.e. centered in the wheel well). However, I decided
to give it a try at 5.5", so I bolted one hanger there, hung a
spring on it and found the rear was way to far back.
56" Alcan Spring Installation
So, I re-attached the hanger at 6.5" (picture 2 and 3) and found
that with a 7" shackle (picture 4), I could get a nearly ideal 45
degree shackle angle in compression and perfectly vertical in droop.
With the length of the shackle, I decided to weld a center brace in
place. I used a scrap piece of 2x4 tubing.
Note: All the welding on this project was done using 7018 welding rod
and 3-12V batteries in series. I used my dual batteries, isolated from
the truck via my quick disconnects and then my old pickup battery. For
welding on the frame, I used 3/32" rod with good results. For the
heavier (1/4 and 3/8") steel on the shackles, I used 1/8"
rod. While this worked OK, I found it harder to keep the arc going, I
suspect the battery voltage gets pulled down too much by the higher
current. I've also had good luck w/ 6011 and 6013 rod, also in the
5/32" size. This is now a permanent part of my trail repair kit.
So, that settled, I welded the driver's side shackle in place. Then, I
laid a few beads of welding rod along the rear shackle mount to beef it
up a bit. I'll probably also tack on an extra piece of steel along the
frame rail for added support.
The passenger side requires dropping the gas tank to properly access
the inner frame rail for welding the hanger on. I had dreaded this
task, but in preparation had run the tank nearly empty. I pulled the
skid plate, drained out the remaining fuel, then loosened the 6 bolts
holding it in place. Then, through the access hole under the rear seat,
remove the filler and vent tubes, and the screws that hold the fuel
pump in the tank and pull it up a bit. Don't forget to separate the
fuel sender connector at the back of the tank. Now, run a floor jack
with a piece of plywood on it under the tank, remove the bolts and
slowly lower it, working the fuel pump free as you go. Now, get the
tank as far away from the truck as possible and weld up the spring
hanger, let it cool, clean and paint it good. Getting the fuel tank
back in was very easy as well.
Ever since I shortened my rear drive shaft after the dual transfer case
install, I've experienced drive shaft vibration to some degree. After
repeated balancing and alignments, I've come to the conclusion that the
angle is too steep (at about 10° currently, more w/ the Alcans)
for a single cardan shaft. Therefore, I've decided to switch over to a
double cardan (or CV) style rear shaft. In this design, a CV joint is
attached to the transfer case output flange and a traditional u-joint
is attached to the rear axle pinion flange, similar to the front drive
line. With a CV-style drive shaft, you need to tip the pinion up to
point directly at the transfer case. A longer spring shackle helps
here, but I still needed some extra shims (6-8 degrees) to get the
desired angle. One benefit of a CV-style drive line, is that it tips
the pinion and drive shaft up higher for better ground clearance.
One problem with the Alcan pack is that it is THICK,
approx 2-3/8". That thickness, coupled with a thick 5° shim,
and my 3/8" thick lower shock mount plate, the e-brake cables
won't clear the top of the spring. So, I fabricated a 1-1/2"
extension for the brake actuators out of some 16ga. sheet metal. I bent
it around a file to make a U shape and drilled 5/16" holes to bolt
to the existing arm and to attach the cable to. This gives me the
additional clearance I need plus additional travel in the e-brake
handle to allow finer control and more leverage. If your run into
this same issus, you can order a set of e-brake extensions here.
A longer rear brake line is also required to handle the extra droop
offered by the Alcan springs. I went with a 6" lift line and also
modified the upper and lower brackets to point at each other to avoid
putting excessive bends in the s/s brake line.
I finally got everything bolted back together. Overall, I ended up with
3 additional inches of lift, it now measures 41" from the ground
to the center of the rear fender well. SInce 2" of this lift was
due to the lowered spring mounts, the springs only have 1" of
additional lift compared to my NWOR springs. They ride fairly flat and
are *so* soft. I've still not decided if I'll stay with the single long
shackle, or go to a two link arrangement or a 3/4 elliptical setup.
Finally got a chance to wheel with these springs, 33 miles on the Dusy/Ershim trail. One word
describes them: WOW!. They really soak up the rocks and are nice
and soft. I need to run the Rancho shocks on 5 to keep the body rocking
to a minimum. I find I'm getting 13" vertical travel measured at
the bumpstops. This should equate to 24" at the outside of the
rim. The 7" long shackle is vertical at full droop and kicked back
about 50-60 degrees at full compression. I'm planning to relocate the
hole in the spring hanger forward about 1/2 to 1" to center the
tire in the wheel well. Based upon that, I would recommend actually
placing the spring hanger 7 to 7.5" forward of the stock location.
The springs flex backwards nicely, even through brand new.
Here's a shot of the new suspension crossed up at Hollister Hills. I
measured approx. 42" of articulation in this spot, 22" front
and 20" rear. Interesting thing with all than flex is that I was
able to drive through this ditch in 2WD (rear Detroit locker - I was
suffering from a cracked Birfield joint at the time) with no
difficulty. Once again, my rear shocks have at least 4" of extra
travel in their present configuration so I've got some room for future
Plans call for some ~59" AOR Orbit Eye springs, 5.5" lift,
relocated shackle hanger and new wider front spring hanger, set into
the frame and gusseted to make a smooth transition from frame to
hanger. The stock Toyota hangers have proven to be my lowest hanging
bit that likes to snag passing rocks.
While the 4" lift Alcan rear springs were working great, I did
finally decide to replace them. Over the years, my front end had gotten
taller as I got it all worked out. Dropped spring hanger and longer
spring shackles plus adding some leaves to support the load up front
all pushed the front higher. Since it was working so well, I did not
want to mess with it. Also, it seemed that the spring bushings and
spring twist was severely limiting the rear axle articulation. Seemed
like the springs "wanted" to flex more, but they were just
binding up and were not able to do so. So, to solve both problems, I
opted to replace the 4" springs with some 5.5" springs and
have the spring eyes upgraded to the Orbit Eye spherical joints. I
think I am really only getting about 3"-4" of lift out of the
In the stock configuration, the Toyota mini-trucks have a squared-off
u-bolt the wraps up and over the spring pack, with a plate and
retaining nuts located below the axle. As such, the nuts and especially
any exposed u-bolt threads are vulnerable to trail damage. Not to
mention the precious inch of ground clearance they eat up. So, with the
spring swap I also did a u-bolt flip, which involves finding a u-bolt
that will wrap around under the axle and pass through a new plate that
sits on top of the springs.
I had earlier installed an AllPro front u-bolt flip
kit. It worked fine for about 6 months, but then I found the
1/2" diameter u-bolts seemed to be bending and stretching and the,
once long, retaining nuts were crushing and deforming with repeated
use. Then a few hours into the Dusy/Ershim trail, I felt some excess
play up front. I tried to torque down the u-bolts but found one nut on
the verge of stripping out, so luckily I had a few spare nuts and
double-nutted as many of the bolt ends as I could. The upper spring
plates were adequate, although I also noticed some bending in them over
time. Since I had already welded on my bumpstop and shock mounts and
steering stabilizer brackets to the AllPro plates, I decided to keep
using them and simply find a heavier u-bolt to use in place of the
In the meantime, I acquired a set of rear u-bolts and spring plates
from a friend. The plates were made from 1/2" steel plate and the
custom-made u-bolts were 5/8" diameter, with 15/16" (24mm)
nuts. They were a joy to work with, they torqued down to 100 ft.lb.
with ease, never felt like they were about to strip out and they stayed
tight. So, for the fronts, I wanted the same secure feeling. I found
that Rancho makes a perfect match for the Toyota axle with their p/n
RS17436 U-Bolt kit (size: 5/8" x 3.25" x 8.75"). They
cost about $25/pr. and are long enough to fit the long inner passenger
side position, and can be trimmed for the other places. Actually, it
took a bit of work to get that inner passenger bolt installed, as the
bolt has to "bend" around the axle housing, due to the slight
tilt in the spring perch relative to the housing. I used a 20T shop
press to put a "slight" bend, perhaps 1/4", in both
sides of the bolt to get it to line up. Interesting note, with the
original AllPro bolts, the same "modification" must be done,
and it can be done by bending the bolt over your knee. Note: If you run
any angle shims up front, chances are you may not be able to fit these
5/8" u-bolts on your axle. In that case, the thinner 1/2"
bolts may be a "better" solution.
Modifying the AllPro spring plates for the larger bolts, requires a bit
of work, as the existing 1/2" holes must be drilled to 5/8"
to accept the new bolts. However, since the inside dimension of the
u-bolt is the same width, regardless of bolt diameter, the larger holes
must be drilled "off-center", that is the inside edge stays
the same, the outside edge gets drilled 1/8" farther out. Without
a milling machine, this is difficult to do. Another option, is to
re-drill the hole to 3/4", which adds 1/8" on all sides of
the hole, allowing the larger bolt to fit. In any event, it is probably
easier to make new plates from scratch, to fit, than to modify and
Back to my 4Runner page.
[Last updated: 17.October.2011]