How-to: Long Arm Suspension
Lift for Jeep XJ Cherokee or MJ
The Jeep XJ Cherokee is a cost-effective way to ply
the back country. These SUVs, built from 1984-2001, offer the utility, space and conveniences often
missing in the more spartan CJs, YJ or TJ Wrangler models. Due to its unitized body and high transfer case
location, the 101.4" wheelbase Jeep XJ Cherokee—or its counterpart Comanche MJ—provides surprisingly good
ground clearance when mildly "lifted."
Arguably, for off-road four-wheeling a unitized body/frame has its
limits. Its structural stamina dictates just how much pounding the vehicle can take.
Off-road racing, trail running and JeepSpeed™ XJ Cherokee models are often reinforcement plated from
bumper-to-bumper. They weigh hundreds of pounds more than stock!
In the years since the XJ Cherokee earned its share of aftermarket lift kits and
axle modifications, these 4x4s have proven their mettle. Longevity is high, and the Jeep XJ
Cherokee provides impressive utility. They built so many of these basic wagons (2.8-million!) that
they're also abudantly available and cheap. The good
news: most XJs survived the "clunker" round-up, and they remain in large numbers.
When lifting a Jeep XJ Cherokee, its similarity to
the YJ and TJ Wrangler become apparent. The front link-and-coil (Quadra-Link) suspension is similar to the
TJ Wrangler, while the rear leaf springs are more like the earlier CJ Jeep and YJ Wrangler.
Installing a suspension lift kit is actually made easier by this configuration, as you will
discover within this project.
If you intend any serious kind of off-road use for your XJ
Cherokee, there are many lift kit approaches available. The comments that I provide here are intended as a
lift kit orientation and overview. Always follow the steps
outlined in your lift kit. Supplement this information with the Jeep XJ Cherokee factory workshop
manual or similar guide.
You will also want to see the article on an
Advance Adapters SYE kit and CV rear driveshaft installation!
This six-inch "long arm" chassis lift is a thorough and well-conceived approach
to raising a Jeep XJ Cherokee. I installed the Full-Traction Suspension kit several years ago. The system has
proven itself time and again in the backcountry. This XJ Cherokee, now fully outfitted with off-road
accessories, doubles as a highway SUV.
Lift Kit pictured above illustrates the front suspension components found in aFull-Traction
Suspension lift kit for the Jeep XJ Cherokee. This well-designed, precise
set of pieces will lift and upgrade an XJ Cherokee. If you want to ply
backcountry with 33" diameter tires, without the need to cut out fender wells, an FTS lift kit is as close to
"bolt-on" as you will find. The rear suspension consists of hefty leaf springs and shock absorbers. FTS
includes these rear pieces plus shocks for the front as well.
significant tools are shown here: a vehicle hoist and sturdy axle stands. Using a fixed lifting point and
supporting the front axle during disassembly and assembly work, axle alignment can be maintained. This saves time
later, when adjusting and aligning the four-link front suspension. If necessary, you can simulate this
approach with four frame stands and a pair of hydraulic floor jacks.
2: Axle suspended and supported stably, the
front sway bar is disconnected and stock shock absorbers removed. Keep parts together to maintain their layout.
Extend the distance between the axle and frame/body to relieve the front
coil spring tension. Remove the track bar as shown here. I like to remove the steering linkage for better
3: Once spring tension is relieved, you can uncouple and remove
the springs. When performing this work, refer to steps in your Jeep XJ Cherokee workshop manual. Springs exert
considerable force and can cause physical injury if not handled properly. Make certain there is no tension on the springs before removing
them. Keep the axle in alignment with the body/frame
items in the chassis lift are the front and rear brake hoses. As the chassis spreads away from the axle, the
hoses become too short. Quality lift kits like this one contain new, longer brake hoses and mounting brackets. I
cap the lines to prevent contamination. After installation of the kit, you will need to bleed the brakes of air and
fill the master cylinder to its "full" mark. At higher mileage, this is a good time to flush fresh brake fluid
through the system.
5: The stock sway bar brackets at the axle
require modification. With the lifted chassis, the original brackets
would be too short. Full-Traction Suspension provides new, weld-on brackets that extend the sway bar link attaching
points. The stock bracket requires cutting and becomes part of the modified link mount system. I use my plasma
cutter for the cutting chore.
6: Having cut the brackets with a plasma
cutter, I dress and bevel the cut
edges. This is a high stress point and requires skilled welding. For those unfamiliar with welding, the chore might
best be sublet to a profession.
Note: In the welding
section of this website magazine, I provide tips
on welding and how to
improve your welding skills. If you have welding or metallurgy
questions, send me a 'Q & A' E-mail. I'll answer promptly.
7: My MIG 170-amp unit and 0.035"
ER70S-series wire with 25% CO2 and 75% Argon gas work well with this
material. Clear the area of all flammables before creating
heat or sparks. Allow metals to cool naturally (at ambient or room temperature), and keep
Ludel's welding tips: Before welding, wire brush away scale from the original brackets and the axle member.
Use a welding amperage and wire speed (MIG or GMAW) that will burn into the thicker plate
material. Concentrate your gun or stick electrode slightly more at the heavier plate side.
The factory bracket is thinner, so weld to deposit some crown at that side. Welding will be in all
positions for this project—go for strength. If you have an SMAW (stick) welder, try 1/8" 6011 or dry 7018
8: When metal
cools completely, paint the new bracket appropriately. Minimize the risk of rusting, especially if you live in an
area with salted winter roads! I have mated the original bracket with the new part, carrying a bead into the axle's
knuckle support. This produces a stronger piece than simply welding the new bracket to the old
9: Note that the lower link
arms, shock absorbers, sway bar, track bar and steering linkage were each removed prior to welding. This is to prevent heat damage or
the risk of the bushings catching on fire. The upper link arms, away from the weld area, help keep the
axle in position until the new parts go into place.
10: This kit
requires redrilling these holes to accept larger hardware. The new track bar will mount to this point. Overall, the
FTS lift kit is well conceived and designed for minimal modifications and relative ease of installation.
Understand, going in, that lift kit work gets involved!
11: Full-Traction Suspension draws
upon the engineering structure of the XJ Cherokee unitized body.
Following the Jeep strength points, FTS attaches hardware with bolt-on, high-grade fasteners. (There is
minimal welding in this entire installation.) Here, the link arm bracket
is fitted at the reinforced side section or "frame."
Note: Long-arm suspension has many advantages. The primary one is the
moderate "arc of radius" (impacting
caster angle) changes when the front axle rises and sets. Ride
quality, steering stability and wheel travel are each dramatically improved with a "long arm" suspension
approach. Though more costly, the long-arm suspension is better for the Jeep XJ
12: The long arms
attach near the transmission cross-member, well back in the chassis. I would not consider a short arm lift kit
unless total lift is in the two-inch range. Beyond that, consider the many advantages of the long arm suspension
13: Side profile
demonstrates the long arm's value. Note the original link arm mount, further ahead in the chassis. Long travel
suspension with short arms will cause dramatic caster angle changes as the axle rises and sets. The cliche
"death wobble" is one side effect of short arm lifts or too little caster angle at the front axle. My approach of
choice is a well-conceived long arm suspension.
14: For the bump
stops to be effective, with the longer springs and a wider gap between the axle housing and frame/body points, a
bump stop spacer must be installed. Here, I drill and tap into the original stop pad. Spacers are part of the lift
kit and come with mounting hardware. I assisted the "self-tapping" bolts, using an appropriate
absorbers must be longer and rated for the new suspension. With long travel, stiff off-road springs and more
unsprung weight mass, these shocks have a job to perform. The shocks, an 'M-Force' design from FTS, have held up
well in a variety of driving environments. Note the installation of a new, FTS dropped pitman arm at the steering
Caution: This kit requires a "dropped"
pitman arm to reduce the slope angle of the raised steering tie-rod. The lift kit includes a new pitman arm, which must be carefully installed using
factory steps. Do not damage the steering gear during the
pitman arm installation. If you need more information on safe
parts installation methods, use the 'Q & A' questionnaire form to submit a question. I will
16: Here, the
track bar, track bar bracket, cross frame brace, steering linkage, springs, shock absorbers and bump stops are all
in place. (Follow the assembly sequence in the lift kit instructions and your factory-level workshop manual.) The
axle has remained stably on the stands, and the link-arm and track bar adjustments will be close to
17: Front axle caster angle is critical. I like
7-plus degrees of positive caster for a Jeep XJ Cherokee front axle. Here, an inclinometer reads the approximate caster, using the factory knuckle support flat as a reference
align the front axle with the rear axle, run a string line in diamond shape. Measure length from the right front to
left rear and right rear to left front. Pick reference points that match from side to side. The spring center bolt
points at the rear and the lower ball joint centers at the front often work well. The string should be the same
length in cross. If so, the front axle lies parallel to the rear axle and also aligns laterally. That's the value
of measuring in-cross or "diamond." Remember those Geometry lessons?
Additional Note: Once the lift
installation is complete and the vehicle sets weighted on the ground, use equipment like
the FasTrax 91025 alignment system to confirm caster, camber and
here to read my
in-depth article on SPC's FasTrax alignment equipment and the techniques that work
well at home or a 4x4 shop.
18: At the rear
axle, the brake hose junction is loosened and pipes capped to prevent contamination. A longer rear brake hose is
essential. When installing new hoses, route them in a manner that will prevent interference with other parts. Make
sure you allow for the full range of suspension movement, the axle's rise and drop. Hyperextending or damaging
a brake hose can be dangerous! Bleed and replenish brake fluid when done.
19: The Full-Traction Suspension rear leaf
springs are a heavy-duty design. They have enough arch to lift the vehicle six-inches at the rear. Note the secure,
reverse "military" wrap of this spring design. This will protect the spring from
separating in the event of main leaf breakage. These springs
have held up very well with added weight, off-road use and plenty of highway miles. After 30,000 miles of testing,
there is no sag or sign of wear!
20: Rear spring
hanger shackles are exceptionally stout. FTS has exceeded the factory design by a wide margin. The springs and
shackles use urethane bushings, and these, too, have held up well. A lift kit designed for off-road use must meet
or exceed the original equipment. Check hardware and bushings periodically for wear.
springs fit neatly into the stock Jeep XJ Cherokee mounting points. The exhaust system may require some attention
or slight tweaking. Make sure all parts can move freely, without interfering with each other. Torque hardware to
specification. Check hardware after the vehicle has been in service for a while.
22: Here, the rear suspension and a new
driveline are in place. A raised chassis calls for a longer driveline. The new rear driveline should be a CV style. The Jeep XJ Cherokee requires a slip yoke eliminator
at the transfer case. With the chassis at curb (normally weighted, on the ground) height, I like a 1.5 to 2.0
degree pinion angle at the rear axle for a CV-type driveline.
23: This is a "CV" or constant velocity style,
Double-Cardan joint. The NV231 transfer case on this Jeep XJ Cherokee now has an Advance
Adapters slip yoke eliminator (SYE) fixed yoke kit that accepts the CV joint. The front end of the
rear driveshaft is a CV joint and the rear U-joint at the axle is a
single Cardan (cross-type) U-joint. Sizing is traditional Spicer 1310, ample for this XJ
24: Here is the rear driveline. Note the double
Cardan CV at the front and single U-joint at the rear. I support all of the vehicle weight on the axles before
measuring rear axle pinion angle. The FTS springs are designed for a CV rear driveline. Curb height angle of the
pinion is approximately two-degrees. Check the angle with both axles on the
ground and the vehicle normally weighted.
25: View from rear forward shows entire front
suspension in place and relationship of parts. This is now a versatile Jeep for off-pavement and highway use. The
vehicle soon received a low-restriction Borla-based exhaust system, heavy duty bumpers, a Warn 9000# winch and
other off-road accessories. At its first off-road test, the '99 XJ Cherokee performed
before 4-Wheeler TV cameras at Moab, Utah. It has done many other trails since.
26: The Jeep XJ Cherokee front suspension is a
marvel! Its centerpiece is a strong beam axle assembly. While a 6-inch lift sounds considerable, this is the
actual amount needed to run 33" diameter tires on an XJ
Cherokee—unless you want to hack out the wheel wells, which I do not advise on a
unibody vehicle. The lift has worked optimally, without tire-to-body interference at extreme axle
look with American Racing alloy wheels and Toyo tires! This is far more than cosmetic, though. The tires are
rugged, and the wheels hold close tolerance. This package provides impressive, useful ground clearance. In a world
of 35"-37" tires, the Cherokee holds its own. Know the limits of a unitized body and how to keep an XJ Cherokee
alive. 33" tires are plenty. Pick trails accordingly.