ARROW 12-Pack 2500 Leaf Spring Kit Installation

 

Notes

For the most up-to-date and current installation
instructions, please visit our website at
www.owlvans.com

• Please read all instructions carefully before installing
Owl products on your vehicle.

• This is a bolt-on spring kit designed for easy
installation using basic hand tools.

• The Owl 12-Pack Springs are shipped in their fully
assembled “Max Spring Rate” configuration. Refer to
the Spring Configuration Chart at the end of these
instructions to properly set up the springs according
to the vehicle’s weight.

Note: The chart serves as a general guide—final adjustment should be
made by the installer and end user to achieve the desired balance of
ride quality and ride height.

• This spring kit is fully removable, allowing the vehicle
to be returned to its original stock configuration if
desired. 

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Parts List

2015-Up, Mercedes Sprinter 2500 12-Pack Leaf Spring Kit

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Tools Needed

1. Quality jack and two jack stands

2. Basic hand tools:

• Wrench and socket set, including:
• Metric sizes: 10mm, 18mm, 19mm, 21mm
• SAE sizes: 9/16”, 7/32” allen

3. Torque wrench

4. Dykes or similar tool for cutting zip ties

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Installation

These instructions show installation on the driver’s (left-hand)
side. Passenger side installation is similar; any differences will
be noted in the steps. 

1.
Loosen lug bolts then safely support the vehicle on an
appropriate lift or jack stands so the rear suspension can hang
freely. Ensure the support method follows the vehicle
manufacturer’s specifications.

2.
With the suspension supported, remove the rear wheels and
tires. Factory lug bolts typically have a 19mm head.

3.
If the vehicle is equipped with a headlight adjuster bracket,
disconnect it at the axle by removing the 10mm nut securing
the L-bracket to the axle. Retain the nut for reinstallation
later in the process. 

4.
Support the rear axle with a jack or stand, then remove the
lower shock bolt using an 18mm socket and wrench. This
allows the axle to droop freely for leaf spring removal.

5.
With the lower shock bolt removed, proceed to remove the
upper shock bolt using a 21mm socket. Retain all OEM
hardware, as it will be reused during installation. Once both
bolts are removed, remove the shock assembly from the
vehicle.

6.
Using an 18mm socket and wrench, remove the lower sway
bar end link bolt on both sides of the vehicle.

Note: Retain all hardware, as it will be reinstalled during
assembly

7.
Remove the brake hose from the factory lift block to free
the line before removing the block assembly. See image
below for reference.

8.
Using a 19mm socket or wrench, remove the U-bolt nuts
securing the axle to the leaf spring, then remove the U-bolts
completely. See image below for reference.

9.
Slowly lower the rear axle until the factory lift block can be
removed. Carefully remove the block and set it aside for
reinstallation later in the process. 

10.
Using an 18mm socket or wrench, remove the forward leaf
spring bolt from the front spring mount. Retain the bolt and
nut, as they will be reused during reassembly.

11.
Remove the lower shackle bolt and carefully lower the leaf
spring onto the axle. Then, remove the axle and shackle
assembly from the vehicle.

It is often easier to perform this step with the help of a
second person to safely guide the spring from its mounts.
Once removed, place the factory spring next to the Owl
12-Pack Spring for comparison and configuration setup.

12.
Note the double military wrap on one end of the Owl 12-
Pack Leaf Spring — this identifies the front of the spring and
must be installed toward the front of the vehicle.

Next, remove the bolt securing the shackle to the rear
of the leaf spring to prepare for installation.

13.
Attach the shackle to the rear of the new Owl 12-Pack Leaf
Spring, ensuring it is positioned perpendicular to the arch of
the main spring. Once properly aligned, torque the shackle
bolt to 100 ft-lbs (136 N·m).

14.
Position the Owl 12-Pack Leaf Springs under the vehicle.
The easiest method is to install the springs upside down,
then rotate them up into position once aligned with the
mounts.

Ensure the brake hose is routed over the spring during
installation.

Note: On RWD vans, the Owl Drop Brackets must be
installed. If they have not yet been fitted, refer to the 2” Lift
Kit instructions included with this package before
proceeding.

15.
With the leaf springs rotated into position, install the
forward spring bolt through the spring hanger and thread
on the nut. Do not fully tighten at this stage—leave the
hardware loose to allow for proper spring and shackle
alignment during final installation. 

16.
Raise or lower the rear axle as needed to align the lower
shackle mount with the leaf spring. Once the holes are
aligned, install the lower shackle bolt and nut, but do not
fully tighten yet—final torque will be applied at ride height to
prevent bushing preload.

17.
Ensure the leaf spring center pin is properly seated in the
spring perch pocket on the axle. Once aligned, jack up the
axle slowly until the leaf spring begins to take load,
confirming correct engagement between the spring pack and
axle perch.

18.
Install the new U-bolts and nuts included with the kit over
the axle and leaf spring assembly. Using a 19mm socket or
wrench, snug all nuts evenly, but do not fully torque at this
stage. Final tightening will be completed once the vehicle is
at ride height.
.
19.
Repeat the leaf spring installation procedure on the
passenger side of the vehicle, following the same steps and
ensuring all hardware is installed and snugged evenly prior to
final torquing.

20.
Cut the 3/8” ID rubber vacuum hose (included with the
spring kit) into equal-length sections. Place one section over
each brake hose where it makes contact with the leaf spring.
Split the hose lengthwise, then wrap and secure it around
the brake hose using multiple zip ties, as shown. This
provides long-term protection against abrasion or chafing
during suspension movement.  

21.
Reinstall the shock and both mounting bolts in their original
positions.

• Lower bolt: Torque to 81 ft-lbs (110 N·m) using an
18mm socket or wrench.
• Upper bolt: Torque to 102 ft-lbs (139 N·m) using a
21mm socket or wrench.

Ensure the shock bushings are properly seated and that the
shock is not twisted before tightening.

22.
Reinstall the lower sway bar link bolt and torque it to 81 ftlbs (110 N·m) using an 18mm wrench. Confirm the sway bar
and link bushings are properly seated before tightening.

23.
If equipped, reinstall the headlight adjuster bracket to the
rear axle, using the hardware removed in Step 3. Ensure
the bracket and linkage are properly aligned and free from
tension through the full range of suspension travel.

24.
If the approximate vehicle weight is known, this is the time to
configure the Adjustable Preload Spacer (APS). Refer to the
Spring Configuration Chart provided at the end of this
manual as a setup guide.

Note: The chart serves as a baseline reference—final
configuration should be determined by the installer and end
user to achieve the desired ride height and ride quality
balance. 

25.
Important: Always install the slider pad with the countersunk
holes facing upward.

• Countersunk bolts: Torque to 15 ft-lbs (20 N·m)
using a 7/32” Allen wrench.
• APS mounting bolts: Torque to 20 ft-lbs (27 N·m)
using a 9/16” socket, ensuring a flat washer and
lock washer are placed under each bolt head.

26.
Reinstall the wheels and tires, then lower the van to the
ground. Torque all wheel bolts on factory steel wheels to
177–187 ft-lbs (240–250 N·m) using a calibrated torque
wrench. Tighten in a crisscross pattern to ensure even seating.

27.
With the vehicle at ride height, torque both the lower
shackle bolt and the front leaf spring bolt to 100 ft-lbs
(135 N·m). This ensures proper bushing preload and longterm suspension performance.

28.
Torque all U-bolt nuts evenly to 125 ft-lbs (169 N·m) in a
crisscross pattern to ensure uniform clamping across the
spring pack.

29.
With the vehicle on the ground at ride height, adjust the
overload engagement pucks as needed to achieve optimal
ride height and ride quality. Fine-tuning puck height allows
for proper load transition and ride compliance based on
vehicle weight and setup.

30.
After 100 miles, recheck bolt torques. 

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Congrats!
Your Installation is complete.  

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RELEASE OF LIABILITY

I, the customer, do hereby release and forever discharge Owl Vans LLC, their agents, employees,
successors and assigns, and their respective heirs, personal representatives, affiliates, successors and assigns, and any and all persons, firms or corporations liable or who might be claimed to be liable, whether or not herein named, from any and all claims, demands, damages, actions, causes of action or suits of any kind or nature whatsoever, whether known or unknown, fixed or contingent, which I now have or may hereafter have or claim to have, as a result of or in any way relating to the following: Parts sold & installed by Owl Vans LLC or parts sold & installed by end-user; any parts sold online, any parts sold online or installed by a re-seller, any parts installed by an installation shop.

It is understood and agreed that this payment is made and received in full and complete settlement and satisfaction of the aforesaid actions, causes of action, claims and demands; that this Release contains the entire agreement between the parties; and that the terms of this Agreement are contractual and not merely a recital.

Furthermore, this Release shall be binding upon the undersigned, and his respective heirs, executors,  administrators, personal representatives, successors and assigns. This Release shall be subject to and governed by the laws of the State of Arizona. 

PRODUCT SAFETY WARNING:

Owl Vans LLC strongly recommends the installation of products be done by a certified mechanic. If
this does not occur, be certain the person(s) installing the product read, understand and follow all
instructions and warnings pertaining to the application before installation. Do not add, alter, or
fabricate any factory or aftermarket parts to increase vehicle height over the intended height of the Owl Vans LLC product purchased. Mixing component brands is not recommended.

Installation of suspension lift kits or any other lifting kits or devices will raise the center of gravity. For this reason, Owl Vans LLC urges that extreme caution be used when encountering driving conditions which may cause vehicle imbalance. Furthermore, the driver’s field of vision and judgment will not be as good due to the height of the vehicle. Due to the installation of larger tires, the speedometer will read slower than the actual speed being traveled and more distance will be required to stop the vehicle. It is the owner’s responsibility to caution and warn any potential driver of the vehicle about these driving and handling conditions. Owl Vans LLC will not be held liable or responsible for damages or personal injuries resulting from the use of lifting devices and or related products. The tires and rims should be changed to sufficiently increase the vehicle’s total overall width and stability to help accommodate lifting devices.

Owl Vans LLC aftermarket suspension products and accessories modify a vehicle for uses which
exceed conditions anticipated by the vehicle manufacturer. The uses include the high performance
demands required during off-road. These conditions vary in the degree of extremity and cannot be
controlled by the vehicle or product manufacturer. If the components within the suspension system or accessories become worn due to frequent and/or extreme use, the safety and reliability of the vehicle is at risk. The maintenance of aftermarket equipment to ensure the vehicle occupants safety is entirely your responsibility. Do not purchase Owl Vans LLC products unless you are willing to accept this responsibility. Do not install any Owl Vans LLC suspension products or accessories unless you feel competent at installing the product without causing present or future injury to yourself or other vehicle occupants; seek an authorized installation center.

Most states have some type of law limiting vehicle height. The amount of lift allowed, and how the lift can be achieved, varies greatly. Several states offer exemptions for farm and commercial registered vehicles. It is the vehicle owner’s responsibility to check state and local laws to ensure that their vehicle will be in compliance.

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This Release of Liability and Product Safety Warning has been read and fully understood by the
undersigned and has been explained to me.