---
title: ARROW 12-Pack 3500 Leaf Spring Kit Installation
description: Learn how to install Owl's ARROW 12-Pack Leaf Spring Kit on your Mercedes Sprinter with these step-by-step instructions. Compatible with 2015+ 3500 vans.
---
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# ARROW 12-Pack 3500 Leaf Spring Kit Installation
## How to install the ARROW 12-Pack Leaf Spring Kit on your 2015+ 3500 Mercedes Sprinter.
### [PDF Version](https://ready.owlvans.com/hubfs/ARROW%20Installation%20Guides/ARROW%2012%20Pack%20Leaf%20Springs%20for%203500%20Installation.pdf?hsLang=en-us)
### 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.
***Please note: 3500 applications do not use the leaf spring sleeves***
******
---
### Parts List
**2015-Up, Mercedes Sprinter 3500 12- Pack Leaf Spring Kit**
| **Part** | **P/N** | **QTY.** | ✔ |
| --- | --- | --- | --- |
| MERCEDES SPRINTER 3500 12 PACK LEAF SPRINGS | | 2 | |
| U-BOLT 12 PACK | | 4 | |
**2015-Up, Mercedes Sprinter 3500 Rear Bump Stop Bracket**
| **Part** | **P/N** | **QTY.** | ✔ |
| --- | --- | --- | --- |
| MERCEDES SPRINTER 3500 BUMP STOP BRACKET DRIVER | SP-RBSM-3500-D | 1 | |
| MERCEDES SPRINTER 3500 BUMP STOP BRACKET PASSENGER | SP-RBSM-3500-P | 1 | |
| SOCKET CAP SCREW, M10-1.50 X 80MM | | 4 | |
| M10-1.50 STOVER NUT | | 4 | |
| M10 FLAT WASHER | | 8 | |
---
### Tools Needed
**1.** Quality jack and two jack stands
**2.** Basic hand tools:
• Wrench and socket set, including:
• Metric sizes: 16mm, 17-19mm, 21mm, 24mm
• SAE sizes: 9/16”
• Torx bit: T-55
• Allen: 8mm, 7/32”
**3.** Torque wrench
**4.** Dykes or similar tool for cutting zip ties.
---
### 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 **16mm 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 **21mm 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.
Retain all hardware, as it will be reinstalled during
assembly.
**7.**
Support the **rear axle** using a **floor jack or transmission**
**jack**, then remove the **four U-bolt nuts** securing the leaf
spring to the axle housing. Use a **19mm socket** for removal.
Ensure the axle remains securely supported throughout this
step to prevent sudden movement
**8.**
Slowly lower the rear axle on the driver’s side until the factory
rear lift block can be removed.
If equipped, remove the block and then raise the axle back
up until it is just below contact with the leaf spring.
**Note**: The **OEM lift block** will **not be reused** unless these
springs are being installed in conjunction with the **Owl 2.0”**
**front and rear lift kit components**.
**9.**
Using a **24mm socket or wrench**, remove the **forward leaf**
**spring bolt** from the spring hanger.
**Note**: On certain motorhome builds, components or
accessories may be mounted in a way that obstructs removal
of the forward spring eye bolt. In these cases, the **bolt head**
**may need to be cut off** and removed toward the center of
the vehicle to allow extraction.
**10.**
Loosen the **upper shackle bolt** to allow movement of the leaf
spring during removal and installation, but **do not remove**
**the bolt completely** at this stage.
**11.**
Remove the lower shackle bolt, then slowly lower the axle
while carefully balancing and supporting the leaf spring.
Once unloaded, remove the leaf spring assembly from the
vehicle.
**12.**
Note the difference between the **front and rear spring eyes**
on the **Owl leaf spring**:
• The **rear spring eye** has the **main leaf centered** with the **bushing**.
• The **front spring eye** has the **bushing positioned above** the **main leaf**.
This distinction ensures the **correct orientation** during installation.
**13.**
Position the **Owl leaf springs** under the vehicle. The easiest
method is to install the springs upside down, then rotate
them up into place once aligned with the mounts.
**Notes**:
• Ensure the **brake line is routed under the leaf spring**, matching the **factory configuration**.
• On **RWD vans without a factory lift block**, the **Owl Brake Line Drop Brackets** must be installed. If not yet completed, **refer to the drop bracket installation instructions** before
proceeding.
**14.**
With the leaf springs rotated into position, install the **forward**
**spring bolt** through the spring hanger and thread on the nut.
Leave the hardware **loose** for now—**do not fully tighten** until
the vehicle is at ride height to prevent premature bushing
preload.
**15.**
Raise or lower the rear axle as needed to align the lower
shackle mount with the leaf spring. Once aligned, install the
lower shackle bolt and nut, **but do not fully tighten at this**
**time**. Final torque will be applied at ride height to ensure
proper bushing alignment and suspension articulation.
**16.**
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 the spring pack is securely positioned in the
perch.
**17.**
Install the new U-bolts and nuts provided 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 performed once the vehicle is
resting at ride height.
**18.**
Repeat this procedure for the passenger side.
**Note**: Steps **19-23** should **not** be performed if a **2” Lift Kit** is
being installed.
For non-2” lift setups, **reinstall the factory lift block** between
the **new Owl leaf spring** and the axle, positioning it **exactly**
**as it was removed** from the vehicle. Ensure the center pin is
properly seated in the block and axle perch before
proceeding.
**19.**
Locate the **factory lift block** removed earlier and identify the
**two T-55 Torx bolts** securing the **OEM bump stop block** to
it. Using a **T-55 Torx bit, remove both bolts** and separate the
bump stop block from the lift block.
**20.**
Identify the left-hand (LH) and right-hand (RH) Owl 3071
Bump Stop Brackets included in the kit.
Refer to the **image below** for proper identification and
orientation before installation.
**21.**
Position the **Owl Bump Stop Brackets** on their respective
sides of the vehicle. Reinstall the rear sway bar to the axle
using the OEM bolts removed in **Step 6**. Start all bolts by
hand but **do not fully tighten** at this stage—final torque will
be applied after alignment verification.
**22.**
Position the OEM bump stop block on top of the axle,
ensuring proper alignment. The counterbore holes on the
bump stop block **must face inward**, toward the mounting
face of the Owl brackets.
23\.
Reinstall the **lower sway bar link bolt** and **snug it securely**,
but **do not fully tighten** at this time. Final torque will be
applied once the vehicle is at ride height to ensure proper
sway bar alignment.
**24.**
Install the included **M10-1.50 x 80mm socket cap screws** as
shown below, placing a washer under both the bolt head and
the stover nut.
Ensure the bump stop block sits flat on the axle tube, then
snug all bump stop bracket and sway bar mounting hardware.
• **Sway bar clamp hardware**: Tighten using an **18mm**
**wrench** and **torque to 81 ft-lbs (110 N·m)**.
• **Bump stop block hardware**: Tighten using an **8mm**
**Allen socket** and **17mm standard socket**, then
**torque to 43 ft-lbs (58 N·m)**.
**25.**
Reinstall the **lower shock bolt** and torque according to
vehicle configuration:
• **3500 DRW vans**: Torque to **125 ft-lbs (169 N·m)**.
Ensure the shock bushing is properly seated before
tightening.
**26.**
If equipped, **reinstall the headlight adjuster bracket** onto
the **rear axle**, using the **hardware removed in Step 3**.
Ensure the bracket is properly seated and that the linkage
moves freely through the full range of suspension travel.
**28.**
Reinstall the wheels and tires, then lower the van to the
ground. Torque all wheel studs on factory steel wheels to the
following specification:
• **3500 DRW**: **140–150 ft-lbs (190–200 N·m)**
Tighten in a **crisscross pattern** to ensure even seating and
proper clamping force.
**29.**
Torque the upper and lower shackle bolts and the front leaf
spring bolt to **125 ft-lbs (169 N·m)** on **3500 DRW vans**.
Verify that the vehicle is at **ride height** before tightening to
ensure proper bushing preload and long-term suspension
performance.
**30.**
With the vehicle at **ride height**, torque all **U-bolt nuts** evenly
to **125 ft-lbs (169 N·m)** using a **crisscross pattern**. This
ensures uniform clamping of the leaf spring pack to the axle
and prevents distortion.
**31.**
Torque the **lower sway bar link bolt** to **81 ft-lbs (110 N·m)**
using an **18mm wrench**. Confirm that the **bushings are**
**properly seated** and the sway bar is in a neutral position at
ride height before tightening.
**32.**
On some 3500 full-bodied vans, the exhaust pipe may be
close to or contact the driver-side shackle. Inspect the
clearance between the exhaust and shackle after installation.
If contact is present or clearance is minimal:
• Have a **helper pull down on the tailpipe** near the hitch.
• Use a **C-clamp to slightly oval the tailpipe** in the area near the shackle to gain the necessary
clearance.
**33.**
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 engagement
ensures smooth transition under load and balanced
suspension performance.
**34.**
After 100 miles, recheck bolt torques.
---
### Congrats! Your Installation is complete.
---
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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.
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this does not occur, be certain the person(s) installing the product read, understand and follow all
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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.
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exceed conditions anticipated by the vehicle manufacturer. The uses include the high performance
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