Dunlop L.412.C.M User manual

L.412.C.M and
L.412.4.C.M
MERCEDES BENZ SPRINTER 408D / 416CDI (1995-2006)
WDB 904 AND 4X4
VOLKSWAGEN LT-46 (1995-2006)
DOUBLE TIRES AND 4X4
INSTALLATION MANUAL
DSCSYSTEMS.NL

2 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

1Foreword 4
2 Introduction 5
3 Very important notes 6
4 Overview 7
5 Instructions for installation 9
5.1 Recommended Tightening Torque 9
5.2 Preparation 9
5.3 Bump Stop Removal and fitting of Upper Bracket Assembly 10
5.4 Fitting of Bellow to Upper Bracket Assembly 10
5.5 Fitting of Lower Bracket 10
5.6 Fitting of Bellow to Lower Bracket 10
5.7 Modification of Load Sensing Valve (LSV) Assembly 10
5.8 Fitting of Inflator Console 11
5.9 Tube Connection and Disconnection, Cutting and Routing 13
5.10 Bellow Inflation 14
5.11 Spring Alignment 15
5.12 Maintenance 15
5.13 Check List 16
6 Installation pictures 17
7 Epilogue 22
Contents
3 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

1 Foreword
This manual provides instructions for the installation of an auxiliary air
suspension kit, developed specifically for the Mercedes Benz Sprinter
408D / 416CDI and the Volkswagen LT 46 (1995-2006).
To ensure correct installation of the kit, it is strongly recommended that
these instructions are read thoroughly before commencing any
installation work. Installation should only be carried out by a suitably
qualified mechanic or specialist installation facility. DSC Nederland will
not accept any responsibility for faults or defects arising from incorrect
installation, which automatically renders the guarantee invalid.
IMPORTANT: Manufacturer’s Declaration Form
A manufacturer’s declaration form is provided with your kit. Following installation
of the kit please ensure that this form is completed, signed by a qualified fitter and
a copy is returned to DSC Nederland by post, fax or e-mail. Our e-mail address is:
[e-mail]
4 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

2 Introduction
THANK YOU FOR CHOOSING AN AUXILIARY AIR SUSPENSION KIT FROM THE RANGE
OFFERED BY DSC NEDERLAND. AUXILIARY AIR SUSPENSION IS FITTED IN TANDEM WITH
THE STANDARD STEEL SPRINGS OF THE VEHICLE SUSPENSION, AND PROVIDES
ENHANCEMENTS IN TERMS OF BOTH THE STABILITY OF THE VEHICLE AND THE
COMFORT OF THE PASSENGER.
VEHICLE LEVELLING
Simply by varying the air pressure in the springs, the vehicle can be
levelled both front-to-rear and side-to-side. Keeping the vehicle level
optimises stability, ensures correct headlamp beam distribution and
reduces tyre wear arising from uneven distribution of weight.
STRAIGHT LINE STABILITY
Straight line stability is greatly increased at higher speeds, and when
subjected to buffeting from cross-winds or large overtaking vehicles.
REDUCED BODY ROLL
Body roll when cornering or negotiating roundabouts is significantly
reduced.
FATIGUE REDUCTION AND WEAR COMPENSATION
Suspension fatigue is reduced, so helping to prevent leaf springs from
sagging under repeated or constant loading. Any sagging already
present can be compensated-for. This is a particular benefit for
motorhomes, which are always fully laden.
RIDE COMFORT
Air springs help to absorb shock loads from uneven road surfaces,
therefore general ride quality is much improved.
5 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

3 Very important notes
VEHICLE UPRATING
Despite the above words of caution, it is possible to upgrade the weight
rating of your vehicle. This must be carried-out by a specialist supplier
that will:
• carry out any necessary modifications in addition to fitting the air
assist kit
• complete documentation as necessary to inform the Vehicle and
Operator Services Agency (VOSA) – a mandatory requirement
• supply and fit a new weight plate to replace the original plate
supplied with the vehicle
This process applies to United Kingdom registered vehicles. The process
in other countries may be different.
SAFETY GUIDANCE NOTE
The following very useful guidance note is available for free download
from the Health and Safety Executive (HSE):
PM85, July 2007 Safe recovery (and repair) of buses and coaches fitted
with air suspension.
The uniform resource locator (URL) for this document is:
http://www.hse.gov.uk/PUBNS/pm85.pdf
IMPORTANT: Gross Vehicle Weight (GVW)
Air assist kits are not in themselves designed to increase the gross vehicle weight
(GVW) rating of a vehicle. They do not legally allow for carriage of a load greater than
the carrying capacity stated on the data plate of the vehicle.
Do not exceed the maximum load specified by the vehicle manufacturer.
• to avoid compromising passenger safety
• to prevent possible damage to the vehicle
• for legal reasons
IMPORTANT: Load Sensing Valve (LSV) Adjustment
If your vehicle is not fitted with an antilock braking system (ABS) then it will have a
load sensing valve (LSV) to automatically adjust braking force under varying load
conditions. This valve must be adjusted immediately after the fitting of an air assist kit
and before the vehicle is driven again on public roads.
If the LSV is not adjusted following the fitting of an air assist kit, it may misjudge rear
load conditions to the extent that the braking pressure applied to the rear brakes is not
correct (e.g. the rear wheels may lock with no load on the rear axle). The
consequences of this in terms of vehicle stability and safety are potentially serious.
6 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

4 Overview
THE COMPLETE BELLOW AND BRACKET ASSEMBLY
ARE SHOWN OF THE LEFT SIDE BY THE DIAGRAM
BELOW.
20
10
1
4
3
20
17
24
21
25
13
6
9
11/12
27
18
2
8
22
26
16
19
23
29
25
14
28
15
7 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

NUMBER PART NUMBER DESCRIPTION QUANTITY
1 49.06.00.1.01 Upper bracket Left 1
2 49.06.00.1.01.03 Support upper bracket 2
3 49.06.00.1.01.04 Stut strip upper bracket 2
4 49.06.00.1.01.05 Base clamp strip upper bracket 4
5* 49.06.00.1.02 Upper bracket Right 1
6 49.06.00.1.04 Lower bracket Left 1
7* 49.06.00.1.05 Lower bracket Right 1
8 49.06.00.1.07 LSV modification bracket 1
9 OPN.LB.170-2.CPL Air bellow 170/2 2
10 DIN 7991-M8x20 Counter sunk bolt M8x 20 4
11 DIN 933-M10x60 Hexagon bolt M10 x 60 4
12 DIN 933-M10x30 Hexagon bolt M10 x 30 4
13 DIN 933-M6x20 Hexagon bolt M6 x 20 2
14 DIN 933-M6x30 Hexagon bolt M6 x 30 1
15 DIN 933-M8x16 Hexagon bolt M8 x 16 6
16 DIN 933-M8x20 Hexagon bolt M8 x 20 2
17 DIN 933-M8x25 Hexagon bolt M8 x 25 2
18 DIN 933-M8x30 Hexagon bolt M8 x 30 2
19 DIN 7991-M8x16 Counter sunk bolt M8 x 16 2
20 DIN 934-M8 Fixation nut M8 4
21 DIN 985-M6 Self locking nut M6 2
22 DIN 985-M8 Self locking nut M8 2
23 OB.0394.06 Flange nut M6 1
24 DIN 125A-M10 Washer M10 4
25 DIN 125A-M6 Washer M6 5
26 DIN 125A-M8 Washer M8 4
27 DIN 127B-M10 Spring washer M10 4
28 M8 Disc spring washer 6
29 OB.43110.000.306 Pipe clamp 13 mm 2
* Left side not in the assembly drawing
NOT IN THE ASSEMBLY DRAWING
• Tie wraps
• Blue hose
• An inflate option
• Declaration of conformity
• Installation manual
8 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

5 Instructions for installation
IMPORTANT: Preparation and Precaution
Before beginning installation, ensure that you have sufficient clearance between
the axle and the chassis. Use a jack if necessary. Install at one side of the vehicle
at a time.
Pay attention to your safety at all times during installation - always use axle
stands to support the vehicle!
The position of the axle stands should be under the chassis NOT under the axle!
5.1 RECOMMENDED TIGHTENING TORQUE
During fitting of the air suspension system, it is recommended that nuts
and bolts are tightened in accordance with the following table...
THE FOLLOWING INSTRUCTIONS MAKE REFERENCE TO THE
DIAGRAMS ON PAGES 17 TO 21 INCLUSIVE.
5.2 PREPARATION
1. Secure the front wheels, use wheel chocks on both sides of both front
wheels.
2. Take the ground terminal from the battery when work to electricity
is involved.
3. Lift the rear of the vehicle till there is working space of approximately
15 cm between bump stop and rear axle.
TIGHTENING TORQUE IN Nm
SIZE CLASS 8.8 CLASS 10.9
M6 x 1.0 11.3 16.5
M8 x 1.25 27.3 40.1
M10 x 1.5 54 79
M12 x 1.75 93 137
M16 x 2.0 230 338
IMPORTANT:
• When both the bolt and nut are
made from steel use either class
8.8 or 10.9
• For all other dimensions and
tighening torques is left to the skills
of a well-trained person
9 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

5.3 BUMP STOP REMOVAL AND FITTING OF UPPER BRACKET ASSEMBLY
1. Remove the bump stop—Figures 1 to 3
2. Insert the two small ‘shoe’ plates into the frame left vacant by removal of the bump stops—Figures 4 and 5
3. Offer the largest part of the upper bracket assembly up to the ‘shoe’ plates. Attach the bracket to the
plates using two M8 x 20mm countersunk bolts—Figures 6 and 7
4. See Figures 8, 9, 10 and 11 : Install three M8 x 20mm bolts to (a) attach the ‘rib’ bracket to the upper bracket
assembly and (b) secure the upper bracket assembly against the chassis. Note that the two uppermost
bolts are tightened until they abut a small plate placed between the bracket and the chassis. This plate
serves to protect the coating of the chassis rail from being marked by the bolt ends.
5.4 FITTING OF BELLOW TO UPPER BRACKET ASSEMBLY
1. See Section 5.9 - “Tube Connection and Disconnection, Cutting and Routing” : Connect a tube to the
bellow. Use black tubing for the left-hand bellow and blue for the right-hand bellow.
2. Manually compress the bellow and then bung the end of the tube to maintain the compressed state
3. Feed the tube through the slot in the upper bracket and offer the bellow up to the bracket. Secure the
bellow to the upper bracket using an M8 x 16mm bolt and an M8 disc spring washer, and an M8 x 20
countersunk screw (already installed in the air bellows) —Figures 12 to 15 inclusive. Do not fully tighten at
this stage because the bellow may require alignment once inflated (see Section 5.11, Figure 30).
5.5 FITTING OF LOWER BRACKET
1. Remove the two bolts from the bracket that attaches the torsion beam assembly to the axle—Figures 16
and 17
2. Place the lower bracket over the axle then reattach the bracket that secures the torsion beam assembly to
the axle, thereby also securing the lower bracket to the axle—Figures 18 and 19
5.6 FITTING OF BELLOW TO LOWER BRACKET
1. Release the bung from the tube. This allows air into the bellow, which consequently expands downwards
towards the lower bracket—Figures 20 and 21.
2. Attach the lower bracket to the bellow using two M8 x 16mm bolts and two serrated washers—Figures 22
and 23. Do not fully tighten at this stage because the bellow may require alignment once inflated (see
Section 5.11, Figure 30).
5.7 MODIFICATION OF LOAD SENSING VALVE (LSV) ASSEMBLY
1. Disconnect and remove the load sensing valve linkage and arm, but retain the pin that connects the
linkage to the bracket at the top end—Figures 24, 25 and 26
2. Using the pin retained from the previous step, install the small adaptor bracket. Place the hook on the
open end of the LSV spring through the hole in the adaptor bracket—Figures 27 and 28
3. Loosen the LSV spring retaining nut and adjust as necessary to achieve the 233mm dimension as shown
in Figure 29. Once this dimension is achieved, re-tighten the retaining nut.
10 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

5.8 FITTING OF INFLATOR CONSOLE
Your kit is supplied with one of these inflator options:
OPTION VALVES Two valves and a small bracket
OPTION MANO
(WITHOUT CONSOLE)
Two valves and two independent 10-bar
pressure gauges
OPTION 1 Two valves in a console with two
independent 10-bar pressure gauges
OPTION 2 Two valves in a console with two
independent 10-bar pressure gauges and a
rocker on/off switch to operate the electric
motor driven air compressor
OPTION 3 Four valves (two for raising the vehicle
(’UP’) and two for lowering the vehicle
(’DOWN’)) in a console with two
independent 10-bar pressure gauges. A
pressure switch operates the electric motor
driven air compressor to keep the air
reservoir of 1.9 litre or 0.5 gallon at pressure
OPTION 3
11 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

Mount the console in a position of your choice whereby it is firmly fixed, has some protection
from the environment (particularly important for the console with gauges) and is easily
accessible. Suggested possible locations include.
‘STANDARD’ CONSOLE
• on the rear bumper
• at the rear beside the license plate
• on the chassis next to a rear wheel
• in a service shutter (motorhomes)
• beside the fuel cap
‘OPTION 1’, ‘OPTION 2’ OR ‘OPTION 3’
Console…
• in the vehicle cabin, within reach and sight of the driver
• Beside, under the driver seat
• in the wall of a cupboard (motorhomes)
• in a service shutter (motorhomes)
‘COMFORT’ PACKAGES
The ‘OPTION 2’ and ‘OPTION 3’ panels, as shown above, are each part of a Comfort
Package that is supplied with a compressor (and also an air reservoir in the case of the
‘OPTION 3’ panel) for ease of spring inflation and ride height setting. For further
information please ask your dealer. The photograph below shows all of the parts of Comfort
Package ‘OPTION 2’ and ‘OPTION 3’.
OPTION.2 OPTION.3
12 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

5.9 TUBE CONNECTION AND DISCONNECTION, CUTTING AND ROUTING
CONNECTION AND DISCONNECTION
Tubes are connected as shown by the diagrams below:
A. Slide a nut over the end of the tube B. Push the tube onto the
connector as far as possible
C. Feed the nut up to the connector,
fully tighten by hand and finally
tighten one additional turn using
spanners
CUTTING
To achieve good sealing and air-tight fitting of tube ends to their
connecting parts, it is very important to cut tubing cleanly and squarely. A
dedicated guillotine action tubing cutter is recommended, or a craft knife
if such a tool is not available. Do not use electrician’s side cutters.
A dedicated tubing cutter
RECOMMENDED
Electrician’s Side Cutters
NOT RECOMMENDED
13 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

ROUTING
Study the underside of the vehicle and decide how to route each branch of the air circuit.
• To minimise the risk of chafing, avoid running tubing over metal edges as much as possible
• Avoid close proximity to heat sources such as the exhaust assembly
• Choose a route that provides as much protection as possible from dirt, debris and any
solid objects that may impact the underside of the vehicle
> It is recommended that tubes are guided alongside brake lines as much as possible.
Use cable ties (‘tie wraps’) to secure tubing to the chassis, taking care not to
over-tighten them.
5.10 BELLOW INFLATION
Once installation of the air assist kit is complete, inflate the air bellow to achieve the desired
ride height via the inflator console taking careful note of the following.
ONCE THE INSTALLATION OF THE AIR ASSIST KIT IS COMPLETE:
• Inflate the air bellows to achieve the desired ride height via the inflator console.
• To achieve a correct ride height, the rear of the vehicle is approximately 6 cm higher than
the front of the vehicle. That will correspondent with a bellow height between 13 cm and
15 cm.
• The correct used pressure is up to the discretion of the installer, but is mostly between the
1.5 bar and the 4.5 bar.
• The pressure for driving your vehicle is depending on the weight of the vehicle and the
condition of the original springs.
• Always keep in mind that you are using air assist suspension, that means helper springs,
they are designed to help. Do not let them take over the original springs.
• Because our system is independent between the left and the right side, it is not a problem
to inflate one side more to achieve the same height on the left and also on the right side.
• Once you know the pressure on your left and on your right side, make good notice of it, so
you can check the pressure of your system every time you start driving.
• The note here below is for extreme situations.
IMPORTANT: Maximum and Minimum Pressure
MAXIMUM PRESSURE 7.0 BAR
MINIMUM PRESSURE 0.5 BAR
Do not exceed 7.0 bar (100 psi), which is the recommended maximum charge pressure
for the air springs. The springs may be deflated if the vehicle is to be stored for a lengthy
period without use, but a pressure of at least 0.5 bar (7 psi) should be maintained at all
times in order to avoid possible compression damage to the springs.
14 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

5.11 SPRING ALIGNMENT
1. With the vehicle standing at the desired ride height, ensure that the
springs are correctly aligned as illustrated above and then tighten
the bolts to secure the bellow to both the upper and the lower
mounting brackets.
2. Always check if the air bellow won’t touch any obstacle
5.12 MAINTENANCE
Following installation, it is recommended that all metal parts are coated
with a protective substance such as body wax.
The system does not require very much maintenance other than…
1. To maintain air pressure in the springs. Much like a tyre, the system
may lose a little air over time.
2. To keep the air bellows clean. It is suggested that, when washing the
vehicle, the bellows are inspected and cleaned as necessary (pre-
ferable by spraying). Look in particular for stones or grit trapped
between convolutes, as this may damage the bellow.
3. Check before and after the winter period the wax coating. Re-wax
when necessarily
15 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

5.13 CHECK LIST
Before driving the vehicle following completion of installation of the auxiliary air suspension system,
please check:
All bolts tightened to the recommended torque (Page 9)?
Air springs set in alignment (Section 5.11)?
Enough free space around the air springs to avoid wearing?
All metal parts wax coated (Section 5.12)?
Manufacturer’s declaration form completed and a copy returned?
A wait of 24 hours is recommended in order to ensure
that the vehicle has maintained its stance and that there
are no air leaks present.
16 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

6 INSTALLATION PICTURES
17 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

1
3
5
7
2
4
6
8
18 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

9
11
13
15
10
12
14
16
19 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021

17
19
21
23
18
20
22
24
20 | INSTALLATION MANUAL | AUXILIARY AIR SUSPENSION | SPRINTER 408D/416CDI AND 4X4 / VOLKSWAGEN LT-46 AND 4X4 (1995-2006) JULY 2021