Jp Magazine – October 2019

(Tina Sui) #1

The BDS 6.5-inch long-arm kit for a 4.0L XJ Cherokee has everything needed to replace our
21-year-old Jeep’s tired suspension. Our kit came with the optional Fox 2.0 shocks, to provide
the optimum ride, and an optional dual-steering stylizer kit (not shown).


OCTOBER 2019 jpmagazine.com Jp 19


lift to accommodate the 35-inch BFG
Mud Terrains. They settled on a 6.5-inch
BDS long-arm kit with the optional Fox
2.0 shocks. It’s a kit that also requires the
t ra nsfer case to be f it ted w it h a slip -yoke
eliminator (SYE) kit and a new CV-style
rear driveshaft to accommodate the
change in the driveshaft angles.


Suspension Travel
In a nutshell, a long-arm suspen-
sion uses longer control arms to reduce
the operating angles, taking stress off
the bushings and arms when the front
suspension is f lexed out. L onger cont rol
arms smooth out a lifted vehicle’s ride
because the suspension geometry remains
closer to stock t ha n it wou ld i f shor ter
control arms were retained.
It’s important to note here that a
vehicle’s ride quality and suspension
travel are not dictated exclusively by the
length of the control arms. The operat-
ing length of the shocks are the limiting
fac tor when it comes to suspension t ravel.
If the stock shocks had 9 inches of travel


and a 6-inch lift was installed, the operat-
ing length of the new shocks would still
dictate how much the suspension would
move—not the height of the lift.
Ride quality depends on several
variables, but the biggest determining factors
are the valving of the shocks and the design
of t he spr i ng s, coi l a nd /or lea f. Shock s w it h
valving tuned to a specific vehicle will give
a better ride than off-the-shelf fits, and
progressive-rate springs will perform better
on- and off-road than fixed-rate versions.
The BDS shocks and progressive-rate
springs in this kit are tuned for the XJ.

Easy Steer
Installing the BDS long-travel kit
probably isn’t for garden-variety DIYer
using jackstands in the driveway and a
set of wrenches rolled up in a plastic tool
holder. Having access to a lift and a good
assortment of tools will make the installa-
tion go a lot easier.
Richard McFarland, the technician at
Dunks who handles most of the suspen-
sion installs and front-end alignments,

replaced the ball joints and all of the
suspension bush i ng s du r i ng t h is i nsta ll.
He also replaced the factory steering gear
with PSC Motorsports’ new Big Bore
steering gear and XD Power Steering
Pump kit to tighten up the XJ steer-
ing—and to help power the BFG 35s in
demanding situations that tend to put a
lot of stress on the factory steering box.
The new power steering pump is
a bolt-in, direct-replacement unit that
provides a higher f low at low engine rpm for
better steering performance. The other half
of the steering upgrade is the gearbox itself.
The 8200 Series has a larger-diameter
piston that increases the torque output of
the steering gear, which makes steering
the 35s on this XJ much easier—especially
when the front Air Locker is engaged.
Installing a long-travel suspension,
along with the other modifications made,
may not fit the needs or budget of every XJ
Cherokee owner. But those that do go this
route will find it’s a good combination for
a daily driver/commuter XJ used to run a
w ide va r iet y of Jeep t ra i ls.

This ’98 XJ Spor t measured 32 inches from
ground to center of front wheelwell trim,
with 13.4 degrees approach angle and 14.
degrees departure sitting on 30x9.50-15LT
BFG Mud Terrains. After the modifications,
ground-to-fender height increased to 44
inches, while approach angle jumped to 64
degrees and departure to 51 degrees. It also
gained almost 3 inches in suspension tr avel.


The BDS long-travel installation up front
required removing everything related to the
XJ’s steering so the coil springs could be
dropped out. This is a good time to address
any engine oil leaks, such as replacing the
rear-main seal and oil pan gasket. It’s also a
good time to rebuild the front axle, which is
what we did. A floor jack is the simplest way
to lower the front axle assembly so the stock
coils can be removed one side at a time.

Chaining up the differential housing after the
coils were dropped out makes it easier to
install the new control arms. We attached the
chains between the Unitbody frame. One end
of the chains attaches to the sway bar bolts,
while a heavy-duty S-hook on the other end
secured it into the frame just above the rear
pocket for the lower control arms.

BDS progressive-rate coil springs (left) give
6.5 inches of lift over the stock XJ coils.
The OEM coil springs on our XJ are the
heav y- dut y ver sions that were par t of the Up
Country option package for the Cherokees.
Free download pdf