JKS 6125 User Manual
Product: Adjustable Control Arms
Part Number: JKS6125
Applications: Grand Cherokee WJ, 1999-04 (rear only)
INSTALLATION
INSTRUCTIONS
517-278-1226 • tech@jksmfg.com • www.jksmfg.com
491 W. Gareld Avenue, Coldwater, MI 49036
Welcome
CONGRATULATIONS on purchasing a set of new Adjustable Control Arms from JKS Manufacturing. We are committed to providing you with the best products available and
your satisfaction is our rst priority.
PLEASE READ these Installation Instructions carefully,
and save them for future reference, as they contain important installation and maintenance information.
Important
COMPATIBLE WITH original 3-link suspension con-
guration and vehicle ride height up to 6.0”.
SUSPENSION COMPONENTS THAT HAVE RUBBER
BUSHINGS must be tightened with vehicle on level
ground and at normal ride height. The springs must be
supporting the weight of the vehicle when the hardware is torqued; or else ride comfort could be affected
and premature bushing wear may occur.
RUBBER BUSHINGS MUST NEVER BE LUBRICATED,
as doing so will impair performance and longevity.
SUPPLIED FLAT WASHER SHIMS must be used to ll
the void between the suspension arm brackets and
control arm bushings. Additional shims are included for
customers installing front Control Arms at same time.
REFER TO FACTORY SERVICE MANUAL for information and procedures not covered in these instructions.
JKS6125JKS Adjustable Control Arm Installation
ATTENTION INSTALLER
Install Adjustable Control Arms ONE AT A TIME for easi-
est alignment of mounting hardware.
Tools Required
Hydraulic Floor Jack and Jack Stands
Metric/Standard Socket Wrench Set
Torque Wrench
Tape Measure
Anti-Seize Lubricant
Hand-Pump Grease Gun
Moisture Resistant Marine Style Grease
Heavy Duty Ratchet Strap *
Factory Service Manual (recommended)
* Asterisk denotes tools that are not required for some applica-
tions. Thoroughly read instructions rst to determine which tools
will be required for your application.
Installation
1. REMOVE ORIGINAL LOWER
SUSPENSION ARM
Raise and support the vehicle chassis with jack
stands positioned in front of the rear lower suspension arm brackets.
Raise the axle housing back into position and sup-
port with a hydraulic jack. HINT: The axle housing
should be evenly supported and the suspension
at normal ride height. Do not attempt removal or
installation with the suspension extended, or the
axle drooped, as this will place tension on suspension arm mounting hardware.
Page 1
Remove the lower suspension arm nut and bolt
Use flat washer shims
to fill void between
bracket and bushing
VOID
9/16” SAE
FLAT
WASHER
from the axle housing bracket. Retain the original
mounting hardware.
Remove the nut and bolt from the chassis rail
bracket. Retain the original mounting hardware.
Remove the original lower suspension arm from
the vehicle.
2. SET CONTROL ARM LENGTH
Adjustable Control Arms are fully collapsed when supplied
from JKS and must be adjusted to the desired lengths
before installation.
The working length of each lower Control Arm can be increased (up to 2.25” longer), decreased (up to 1.0” shorter), or exactly the same as the OE suspension arm.
Determine ideal Control Arm length for your ap-
plication by considering factors such as:
 Length of OE suspension arm
 Tire Clearance
 Pinion Angle
Rotate adjustable end of Control Arm until the
desired length is achieved.
Adjust corresponding Control Arm to exact same
length.
3. INSTALL ADJUSTABLE CONTROL ARM
The factory suspension arm brackets on the chassis and
axle are wider than the Adjustable Control Arm bushings.
Therefore, it will be necessary to insert at washer shims
between the bracket and bushing to ll this void.
IMPORTANT: Each Control Arm requires three (3) at
washer shims for installation. Two (2) at washers are
required for the chassis end of the Control Arm, and
one (1) at washer is required for the axle end.
For your convenience, enough at washer shims have
been supplied to accommodate installation of front and
rear lower Control Arms.
Apply anti-seize lubricant to bolt threads of original
mounting hardware.
Mount the non-rotating (BLACK) end of Adjustable
Control Arm to the chassis rail bracket with the
greaseable tting facing up.
Insert two (2) at washer shims – one on each
side of bushing – to ll the void between the chas-
sis bracket and Control Arm bushing. HI N T: Flat
washers must be installed to ensure proper bushing performance and reliability.
Install the original mounting bolt and nger tighten
the nut. DO NOT torque mounting hardware until
instructed.
Mount the rotating (GOLD) end of Adjustable Con-
trol Arm to the axle housing bracket.
Insert one (1) at washer shim to ll the void
between the axle bracket and Control Arm bushing. HINT: Flat washer must be installed to ensure
proper bushing performance and reliability.
Install the original mounting bolt and nger tighten
the nut. DO NOT torque mounting hardware until
instructed.
HI N T: If mounting bolt is difcult to install due to misalignment of Control Arm bushing with mounting bracket, either
(1) adjust height of axle housing with hydraulic jack, (2)
move axle housing into position with a heavy-duty ratchet
strap, or (3) temporarily disconnect track bar until mounting
holes align.
2 Page
JKS6125
4. TIGHTEN MOUNTING HARDWARE
Once both Adjustable Control Arms have been
properly installed, lower the vehicle to the ground
until coil springs are supporting the full weight of
vehicle.
Using a torque wrench, tighten the mounting hard-
ware to 130 ft-lbs.
JKS Adjustable Control Arm Installation
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