Dunlop L.312.C.M User manual

www.dunlopsystems.nl
Auxiliary Air Suspension
November 2018
Installation Manual
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
L.312.C.M
Mercedes Benz Sprinter 200/300 Series (1995—2006)
Volkswagen LT 28-35 (1995—2006)

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
2
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
1. FOREWORD .......................................................... 3
2. INTRODUCTION .................................................... 4
3. VERY IMPORTANT NOTES........................................ 5
4. COMPLETE ASSEMBLY ............................................ 7
5. INSTRUCTIONS FOR INSTALLATION......................... 8
5.1. Bump Stop Removal and fitting of Upper Bracket Assembly...............8
5.2. Fitting of Lower Bracket to Axle ....................................................9
5.3. Fitting of the Air Bellow..............................................................10
5.4. Fitting of Inflator Console...........................................................12
5.5. Tube Connection and Disconnection, Cutting and Routing ...............13
5.6. Spring Inflation.........................................................................14
5.7. Spring Alignment ......................................................................15
5.8. Maintenance.............................................................................15
6. EPILOGUE ............................................................16
CONTENTS
© 2017, DSC Nederland B.V.
DSC Nederland B.V.
Het Wegdam 22
7496 CA Hengevelde
Nederland
Tel. :[phone]
Fax.:[phone]
e-mail: [email protected]
Website: www.dunlopsystems.nl

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
3
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
1. FOREWORD
This manual provides instructions for the installation of an auxiliary air
suspension kit, developed specifically for the Mercedes Benz Sprinter
200/300 series and the Volkswagen LT 28-35 series (June 1996 to June
2006 model Years). To ensure correct installation of the kit, it is strongly
recommend 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.
This kit is suitable for motorhomes and other vehicles with a minimum
rear axle load of 1700kg (3750lbs).
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:
[email protected]

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
4
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
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 passengers…
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.

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
5
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
3. VERY IMPORTANT NOTES
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
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.
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.

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
6
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
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

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
7
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
4. COMPLETE ASSEMBLY
The complete (left-side) auxiliary air suspension assembly is shown by
the diagram below...
1 Upper Bracket
2 Load Sensing Valve Bracket
3 Mounting Plate ‘A’
4 Mounting Plate ‘B’
5 Air Bellow (170mm Nominal Diameter, 2 Convolute)
6 Lower Bracket Plate
7 Lower Bracket

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
8
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
5. INSTRUCTIONS FOR INSTALLATION
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!
5.1 Bump Stop Removal and fitting of Upper Bracket Assembly
i. Remove the bump stop. If necessary use a
long screwdriver or other implement to
prize the stop free from its mount.
ii. Offer the upper mounting plate assembly
up to the bump stop frame. Slide the two
parts*of the assembly apart and into the
frame, as indicated, until they seat snugly
with their M8 holes in alignment.
*The two parts are shown as and in the diagram of Section 4

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
9
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
iii. Offer the upper mounting bracket up to the
mounting plate such that the M8 holes are
in alignment. Attach the bracket to the
plate using a M8x20 bolt and flat washer.
5.2 Fitting of Lower Bracket to Axle
i. Place the lower bracket over the axle,
ensuring correct orientation as shown
ii. Mate the tongue on one end of the lower
bracket plate with the slot in the lower
bracket, then swing the plate as shown
until it contacts the flange on the lower
plate with holes in alignment
iii. Secure the bracket to the plate using a
single bolt, two flat washers and a nut

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
10
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
5.3 Fitting of the Air Bellow
i. Connect the air tube to the bellow, noting
colour designation : Black tube to left-hand
spring, Blue tube to right-hand spring.
Simply push-in the tube as far as it will
travel and release (see Section 5.4). Feed
the other end of the tube through the large
hole in the upper bracket.
ii. Unscrew and disconnect the load sensing
valve (LSV) linkage from the existing
arm . Unscrew the arm from the axle
bracket and remove it.
iii. Position the bellow between the chassis and
the axle, and attach the bottom plate of the
bellow to the lower bracket using two bolts
and two flat washers. Do not fully tighten
at this stage because the bellow may
require alignment once inflated (see
Section 5.7).



L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
11
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
iv. Attach the top plate of the bellow to both
the upper bracket and the load sensing
valve bracket using two bolts and two flat
washers. Do not fully tighten at this stage
because the bellow may require alignment
once inflated (see Section 5.7).
v. Attach the load sensing valve linkage to the
bracket using a bolt, two flat washers and a
nut.
Complete and fully installed auxiliary air suspension system

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
12
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
5.4 Fitting of Inflator Console
Console with Valves Only…
• on the rear bumper
• at the rear beside the license
plate
• on the chassis next to a rear
wheel
• in a service shutter
• beside the fuel cap
Console with Valves and Gauges…
• in the vehicle cabin, within reach
and sight of the driver
• in the wall of a cupboard
(motorhomes)
• in a service shutter
‘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.
Option Valves Option 1
Option 2 Option 3
Your kit is supplied with one of the inflator options shown above…
• ‘Option Valves’, having two valves and a bracket (above, top-left)
• ‘Option 1’, ‘Option 2’ or ‘Option 3’, having both valves and pressure
gauges
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...

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
13
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
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
Connection and Disconnection
Tubes are connected as shown by the diagrams below...
5.5 Tube Connection and Disconnection, Cutting and Routing
A B C
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

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
14
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
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.
5.6 Spring Inflation
Once installation of the air assist kit is complete, inflate the springs via
the inflator console taking careful note of the following...
Maximum and Minimum Pressure
Maximum Pressure 7.0bar Minimum Pressure 0.5bar
Do not exceed 7.0bar (101psi), 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 0.5bar
(7.25psi) should be maintained at all times in order to avoid
possible compression damage to the springs.
Use cable ties (‘tie wraps’) to secure tubing to the chassis, taking
care not to over-tighten them.

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
15
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
5.7 Spring Alignment
Spring out of alignment—
mounting plate axes
offset
Spring in alignment—
mounting plates parallel
and coaxial
5.8 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…
♦ to maintain air pressure in the springs. Much like a tyre, the system
may lose a little air over time.
♦ to keep the air bellows clean. It is suggested that, when washing
the vehicle, the bellows are inspected and cleaned as necessary
(preferable by spraying). Look in particular for stones or grit
trapped between convolutes, as this may damage the bellow.
CAUTION!
Before fully tightening the bolts that secure the air spring to the
upper and lower brackets, set the vehicle at ride height (spring
height approximately 13.5cm) and ensure that the springs are
correctly aligned.

L.312.C.M
Mercedes-Benz Sprinter 200/300 Volkswagen Crafter 28-35
16
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
www.dunlopsystems.nl
6. EPILOGUE
DSC Nederland hopes that you enjoy the benefits that your DUNLOP air
suspension system will provide for you. To ensure optimal performance,
we advise that you have your system checked frequently by qualified
personnel. As recommended in the fitting instructions, it is important to
coat all the steel parts with a protective substance such as body wax.
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:
[email protected]
As a condition of your warranty, modifications to the system may only be
carried out by personnel of DSC Nederland.
Enquiries
For general enquiries please contact one of our dealers. You can find
them on our website.
www.dunlopsystems.nl

www.dunlopsystems.nl
DUNLOP and the Flying D Device are trademarks of Dunlop International Group and are used under license by DSC Nederland B.V.
DSC Nederland B.V.
Het Wegdam 22
7496 CA Hengevelde
Nederland
Tel. : [phone]
Fax. : [phone]
e-mail: [email protected]
Auxiliary Air Suspension