Coil Spring Conversion
(Classic, 4.0/4.6)
Introduction
Pros and Cons of Air
Versus Coils
Coil Conversion Kits
Getting Rid of Residual
EAS Fault Messages
Chris Compton's
Experience (4.0)
Todd Pfortmiller's
Experience (Classic)
More Information
Introduction
At the first hint of air suspension trouble, the Luddite
contingent
-- so prominent among Land Rover Owners -- advocates replacement
of that pesky airbag system with "good old coil springs". Of course
these
are the same folks who were so reluctant to admit that coil springs
were
better than the medieval farm cart springs used on their Series Rovers.
As readers of this website will be aware, I am a fan of the Range Rover
Electronic Air Suspension, but can totally understand the motivation of
those who are tired of spending money on it and feel they would rather
do away with its hassles once and for all, converting back to good old
fashoned coil springs. There is no doubt that coil springs are more
reliable, and they also
tend to give a softer ride, a thing many Range Rover owners (including
me) sorely miss from the old Classic days.
Accordingly, this page attempts to relay some of the options for coil
conversions and relate the experience of some actual owners. (Photo above is of Chris Crompton's
coil-sprung 4.0 demonstrating its articulation).
Pros and Cons of Air vs Coils
But first -- a bit of debunking about air suspensions. Firstly, every
truck uses one form of air spring -- it's called a "pneumatic tire".
Even the use of air-filled rubber bags to replace coil or leaf springs
has been standard for years on large trucks. The only
new
aspect is the Range Rover's electronic control system for varying ride
height. The standard question posed by the Luddites is "What do you do
if an air spring fails due to off-road stresses?" My standard response
is "what do you do if a leaf breaks?" (a not uncommon occurrence, which
leaves you stranded). If a spring breaks on an air sprung Range Rover,
you just give
a light-hearted shrug and drive it home -- the special bump stops are
designed to act as emergency springs. As Bill Adams says, "Actually, having
worked on both types of suspension as well as Series leaf and
parabolics, the air suspension is far and away easiest to work on. The
risk of field failure is pretty much moot once you know how the system
works, besides I'd rather install an air spring in the field than a
coil spring (those break too). It can all be bypassed with a few short
bits of wire. [For details of how to do this see the Air
Suspension
Manual Operation page]. The air suspension is just too cool.
You don't get 5 ride heights with coils! Or load leveling, or high
center detection. I love the lowering button!"
Coil Conversion Kits
Classic
On the air-sprung Classic models, in which Land Rover was
experimenting
with the new air suspension controls, there seems to be a propensity to
revert to the "limp home" mode too readily whenever a fault of even a
minor nature is detected in the system. On these models,
therefore,
coil spring conversions seem to have gained the most popularity, and
can be
less
expensive than repairing the air suspension. Converting back to coils
is more or less a
no-brainer, as these models were designed for coils in the first place.
This
fact greatly simplifies the conversion, reduces the number of
components needed, and increases the range of choices of coil springs.
Many of the major mail-order parts houses now provide complete kits for
converting your Classic back to coils. Conversion consists of
changing
the air bags for spring cups and springs, and disconnecting the
electronics.
Examples of available options include the "air suspension conversion
kit" for $349 from Atlantic British,
depicted at right. It includes 8 bolts 10mm x 30mm, 32 Washers 10mm, 8
Nuts – Self Locking 10 x 1.25,
4 Cap – Rubber Tubes, 4 Ties Nylon 6”, 4 Spring Seats Front/Rear, 4
Spring Retainers Front/Rear, 2 Springs Left Front – Blue/White, 2
Springs Left Rear – Green/Pink, and a set of instructions. They have
several other variations including a kit with everything but the
springs (you choose your own) for $99, and Heavy Duty and Old Man Emu
spring kits.
Another option is the coil conversion kit from Strutmasters.
They have
long been in the business of making replacement parts and coil
conversions for a wide range of vehicles, not just Land Rovers. Their
kit, illustrated below, contains everything needed to convert to coils
and comes with a lifetime warranty. They now offer a choice of standard
height or 2 inch lift conversion kits.
John
Robison of Robison Service
offers a coil spring conversion for about $1200 (parts and labor),
making
the final vehicle height a bit higher than standard. The East
Coast Rover website has pictures
of a Safari Gard Stage II coil conversion costing about $600. Rovers North also now has its own
coil conversion kit for the Classic, as does MotorcarsLtd.
To prevent error messages from appearing, you can remove the ECU, fuses
and
relays for the system, which are under the left front seat, accessed by
removing the side panel covers from the seat base. Or, just remove the
fault indicator bulbs!!
4.0/4.6/p38
John
Robison was one of the first shops to offer a coil conversion for
the 4.0/4.6, initially costing about $2,500. Several aftermarket
suppliers now have lower
cost versions. For example, Motorcars Ltd now offer one for under $800.
Strutmasters
(who have
long been in the business of making replacement parts and coil
conversions for a wide range of vehicles, not just Land Rovers) offer
an extremely economical
conversion kit for the 4.0/4.6 for $495.
It
comes with everything needed to convert to coils
and includes a lifetime warranty.
If you do this conversion there was previously no way to
prevent the BeCM issuing fault messages and irritating beeps for ever
after; fortunately
now Atlantic
British
has a complete kit including
a specially-developed box of electronics ("EAS Override Module") to
fool the ECU so this does not happen (their part number
9520BLD). You can also purchase this module from them
separately and do your own coil conversion from any supplier you
like.
|
|
Coil conversion kit for 4.0/4.6
(photo courtesy of Atlantic British)
|
EAS Override Module (photo
courtesy of Atlantic
British)
|
The photos above illustrate the complete Atlantic British
kit including their specially designed "EAS Override Module"
mentioned above. The standard duty kit
($849 including the override module) includes aluminum spring perch
adapters designed by AB, custom
made coil springs designed to replicate standard ride height and
provide maximum articulation, and step by step
instructions. A heavy duty kit is also available
($949) with beefier coils designed for a higher ride height and
heavier loads.
I recently discovered (Sept 2004) that British
Pacific
has developed their own heavy duty conversion set, which uses upgraded
Old Man Emu springs, renown for their off road ability. Their kits also
include hardware and detailed fitting instructions with photos, plus
their own EAS override 'black box' to tell the BECM computer that
everything is fine. The conversionn has been extensively road tested,
and found to give a superb ride. Vehicle height is just a touch higher
than the middle setting on the stock air suspension. The kit uses the
stock 4.0/4.6 shocks. The price is $799.95.
|
Coil conversion kit from British
Pacific, using heavy duty Old
Man Emu (OME) springs.
|
A new development in this field is the Arnott
Industries coil conversion kit, also using existing shocks, for
$579. Typical of their thorough approach, their spring seats are CNC
machined from solid 6061-T6 aluminum alloy, and the mounts are designed
to
bolt directly to the current suspension brackets. The kit features
powder coated variable rate coil springs made in the USA, and includes
step
by step instructions on how disarm your EAS alarm. Strutmasters
makes a simpler kit with fewer components for $495.
Christian Kuhtz recently
pointed out (September 2006) that The Rover
Connection also now has an excellent kit for the 4.0SE. If you
already have some coil springs left over from other vehicles, they can
supply the necessary mounting hardware kit for only $250! This includes
upper and lower spring mounts, spring seats, and rubber isplators. Or,
you can get the the complete kit (see
photo below) with custom progressive coil springs made in the
USA for $499. In either case, you get complete instructions for
disabling the EAS electronics.
Getting Rid of EAS Fault Messages
If you convert to coil springs, the EAS system will get confused
and constantly issue "EAS Fault" messages accompanied by annoying
beeps. The different conversion kits have different methods of dealing
with this problem, using proprietary electronic workarounds that fool
the BeCM into thinking everything is fine. If your kit does not address
this problem, or you do your own conversion, you can use the following
home-grown method discovered by Dennis Altman. To clear the "EAS Fault,
slow 35mph max" warning from the dash, put two
jumpers on the connector to the ECU, one from pin 7 to pin 18 (ground )
and the other from pin 25 to pin 1 (+12v). When you start up you will
get a soft beep and short "EAS manual" message, then normal message
center operation will resume. (This also work whenever you have the ECU
disconnected - eg when in hard fault,
waiting to get a reset and using manual operation).
Chris Crompton's Experience (4.0/4.6)
Chris Crompton of Abu Dhabi is one who finally got sick of
dealing with EAS problems and went to a coil setup on his 4.0. Chris
reports "I’ve finally got the
suspension pretty much how I want it, the car is running on OME springs
and
shocks, but with an extra lift at the front and back. I have also
relocated the front shock mounts to give me a bit more travel, and
welded an
extra inch onto the axles where the bumpstops meet to stop the bigger
tyres
catching the wheel arch.
"The overall set
up is now running
about 4.5” higher than a Rangie on standard EAS setting with OEM tyres,
I’ve
got about 1.5” raise from having larger diameter tyres and 3” from
the suspension."
|
Chris Crompton's RR on the ramp
with the new suspension.
|
Todd Pfortmiller's Experience (Classic RR)
Todd has a 1995 Classic
Range Rover, and reports: "We replaced my air bags with OME 761 Front
(MED) and OME 764 Rear (MED) and removed the sway bars. [Editor's note: Remove sway ars at your own
risk -- it adversely affects pavement handling and can make the vehicle
dangerous]. I ended up at
the same height as my high profile air bag setting and the front and
rears are almost perfectly even, with .25 inch higher in the rear.
These were recommended by Bill at Great Basin Rovers and I think he did
very well.
I do have a non-winch ARB on the front and some tools/supplies in the
rear. Now I will have to mount some 235/85r16's in the near future!
Things I've noticed. The coils are much more linear and smoother in
their action. The lean is not to bad, much more noticeable, if you are
a seafaring person. But the tires always feel planted. Some cornering
testing away from the general population has re-calibrated my seat of
pants flip-o-meter (hopefully). Some light off roading has felt less
jarring also."
More Information
Alan
Bates's coil conversion and lift is described at this link
(he used a Motorcars Ltd kit).
If
you have had experience with coil conversions, please write in with
your experiences!
