Project Mini - Front Straight Axle Swap - Part 1
|Author: Jay Kopycinski
With the rear suspension complete, we turned our
attention towards the front end of our truck. The IFS suspension
is fairly capable for many types of wheeling. However, for harder
rock crawling we prefer a straight front axle setup for improved
travel capability and increased durability. To gain these traits,
we'll be swapping in a '84 model front axle and converting to
leaf springs. As we did on the rear suspension, will be doing some
homebrew mods in some places and adding some aftermarket parts too.
Follow along as we show you how we did it......
| Removing All the IFS Components
| Starting the front suspension disassembly
|| The pile of IFS parts we removed
We started by parking the truck with the front
frame rails supported by jack stands placed just behind where we
our shackle hangers to end up. Next, we unbolted just about everything
related to the front IFS suspension and drivetrain. We removed the
pitman arm from the steering box, but let the box in place. We removed
the front driveshaft and plugged the brake lines to prevent fluid
With everything removed that could be done without
cutting, we were ready to proceed with the liquid wrench. We cleared the
area of all our tools and parts and took a look. There were quite a few
brackets left hanging from the frame. I lit the torch and went to
work. About an hour and a half later I had all the remaining IFS hangers
removed. Another hour and a half later and we had the frame rails ground
smooth and had a clean canvas on which to start our swap.
| Here's all the IFS brackets on the frame
|| Here's all the IFS brackets on the floor
|| The frame rails are looking cleaner already
|| Frame rail after being ground smooth
| Installing the Front Spring
|Dropped front spring mount we fabricated
Our overall plan for the front suspension was to
use dropped front mounts and mount the shackle below the frame rail.
We prefer this method over running highly arched springs and it would offer
several benefits. It would give us good lift while keeping the springs
fairly flat. This method is also a bit stronger, keeps the ride
allows the springs to flex very well, and allows the springs to
bend backwards well without fatiguing them rapidly. The only downside
is a small loss of approach angle at the front of the frame when
compared to higher arched lift springs.
|Holding the front mount in place with a
We fabricated a front hanger mount that dropped the
front spring mounts about 2 1/2" when compared to a normal
axle truck. More detail on this type of mount can be found on my
Front Suspension Tech page.
The front spring hanger was positioned under the
front frame crossmember and held in place with a floor jack. We then
welded the mount in place. Our mount was positioned such that the center
of the spring eye holes were spaced 2 1/8" rearward from the front
face of the front frame crossmember (the one with the large holes punched
| Springs and Shackle Hangers
|We used stock rear shackle hangers up front
We had decided to use our old rear springs as the
basis for our front hybrid spring packs. We used just the rear main leaf
to mock-up our front spring mounting. We had also decided to use the
stock rear shackles (3 1/2" eye-to-eye) up front and mount the
shackles under the frame rail using a set of stock rear shackle hangers.
This setup will provide us with plenty of shackle movement without any
problem of the shackle hitting the frame rail, as is sometimes found
with a shackle mount tube sitting in the frame rail.
Energy Suspension bushings (kit #8.2103G) were used in the spring packs
and shackles. The front spring eye was bolted to our dropped mount using
3/4" hex bolts and nyloc nuts.
Using only the main leaf from one of our stock
rear spring packs, we estimated where we wanted our hangers mounted
and tack welded one in place. After several tries of articulating the
main leaf and shackle combination and moving the hanger, we settled
on a final location. We chose a center-to-center distance of 45 1/4"
between the front mount hole and the rear shackle hanger hole.
We marked this location and removed the tack welded hanger.
|A homebrew jig to align the shackle hangers
To ensure we got both hangers located correctly
we used a little trick to hold them in place. After inserting the
new poly bushings in the hangers, we slipped a piece of " electrical
conduit through the bushings. With both hangers slid snugly over the
conduit, we adjusted the distance between the two hangers to match
the mount separation at the front of the truck. With our little jig
adjusted, we used a floor jack to lightly hold the assembly under
the truck. Final adjustments were made and the hangers were tacked
in place. We removed the tube and bushings and final welded the
hangers to the frame.
| Energy Suspension poly bushings were used
|| Aligning the rear shackle hangers
|| Checking the spring movement up front
| Mounting the Springs and Axle
We built five leaf packs for our front axle
using the following leaf stack:
Main leaf: 0.280" thick, 47" long (original rear leaf)
Second leaf: 0.280" thick, 47" long (original rear mil wrap leaf)
Third leaf: 0.280" thick, 45" long (a Mazda 2WD leaf)
Fourth leaf: 0.280" thick, 40.5" long (original rear third leaf)
Fifth leaf: 0.280" thick, 34" long (misc. 2WD leaf)
We mounted our front spring packs and attached the front axle to the
leaf packs using a u-bolt flip kit from All Pro Off Road. Prior to
attaching the plates, we welded a homebrew steering stabilizer bracket
to the driver side u-bolt plate. This allows us to install a steering
stabilizer from this point to a bracket added to the tie rod. I prefer
to mount the stabilizer to the tie rod rather than to the draglink so that the
stabilizer and both mounting points always travel together. This ensures
consistent movement from the stabilizer and makes component clearance
We also positioned the front axle slightly offset from the spring center
pin. With our new spring setup, we chose to move the axle backwards 1"
on the spring pack. To do so, we drilled two new 5/8" diameter holes
in the springs perches, offset 1" from the center of the perch. We also
drilled matching holes in the u-bolt flip plates. Also, to beef up the
stock perch a bit, we had previously welded a 1/4" steel plate to the
top of each perch.
| All Pro flip kit...plates and u-bolts
|| Steering stabilizer mount and new center pin hole
|| Added perch plate and redrilled center pin hole
Stay tuned because next month we'll add our steering, brake upgrade,
shock mounts, and driveshaft to complete the front suspension.
Thanks for reading!
- Project Mini -
- Project Mini - Bobbed
- Project Mini - Rear
Suspension - Part 1
- Project Mini - Rear
Suspension - Part 2
- Toyota Section
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