Coil Spring Conversion (Classic & P38)

Chris on ramp
Introduction
Pros and Cons of Air Versus Coils
Coil Conversion Kits
Getting Rid of Residual EAS Fault Messages
Chris Compton's Experience (P38)
Todd Pfortmiller's Experience (Classic)


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 KitsAB Kit
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.

Strutmasters Coil Conversion Kit

Strutmasters kitLift blocks for Strutmaster conversion kit

Strutmasters Classic Coil Conversion Kit ($339)

Strutmasters Classic coil conversion kit with 2 inch lift ($495). 


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!!

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. 

kit

module

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.

BP Coil Conversion Kit



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.

Conversion4

strutconv4lift blocks

Strutmasters 4.0/4.6 Coil Conversion Kit ($495)

Strutmasters 4.0/4.6 Coil Conversion Kit with 2 inch lift ($545)


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.

Rover Connection kit


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). (Note: As alert reader Robert Seccomb points out, the jumpers go on the back of the connector, under the shield, and the connector remains attached to the ECU). 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).

Dave Paget from Gambia offers this alternative method: "I usually fit the BEARMACH spring conversion ... I have worked out that after you have fitted and welded the base plates to secure the springs, you can make a fairly minor modification to the wiring to get it to come up “EAS MANUAL”. What you do is open up the area around the BeCM then on the plug for the EAS, you cut the blue with white trace wire (pin 18) and the blue and grey wire (pin 9) from the plug. The blue and white wire is extended and fitted to the POSITIVE terminal at the front of the BeCM, ideally with a 5 amp in line fuse. The blue and grey wire is extended and joined to the NEGATIVE terminal at the rear of the BeCM. Tape up the wires that have been cut in the loom, to insulate them separately. Job done.   You will then be able to remove the compressor from the box, giving you a nice under bonnet cubby box. Then you should remove the switch for the ride height, and remove the plug from it and return the switch. You can then also remove the ECU.
When you turn the ignition on, you will see the dash display showing “EAS MANUAL”. You can check the dash display before removing anything, after doing the wiring, if you want to check it out before removing anything."

Chris Crompton's Experience (P38)
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."

ramp2

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 bars 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."



 

 

 

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Page revised February 1, 2012