Air Spring Replacement

Introduction :
The Air springs on late model Range Rovers usually need replacing before a coil spring would sag significantly -- a cause for much complaining among Range Rover owners, especially in the early days when the "Genuine" replacements were extremely expensive (close to $US300 each) and in short supply.

Cautionary Note: The E.A.S system uses air at very high pressure -- 10 bar or 150 psi. Be careful when doing any operation on it; according to the shop manual the air should be removed from the system before repairs are carried out.
Depressurizing the System:
The manual advises depressurizing the system before replacing springs, but their procedure for doing so requires the Test Book! We lesser mortals without such facilities simply skip this step (do so at your own risk of course). If you are in the field with a blown air spring, it will already be depressurized anyhow. If it is not blown and still has air in it, you can partly depressurize it by jacking up the chassis so the spring is well extended. If you want to depressurize the air tank, you can SLOWLY unscrew the drain plug -- it has a notch in the threads so when partly undone it lets the air escape without firing the plug out like a bullet.

Disabling the Air Suspension:
You don't want the suspension to adjust itself up and down while you work on the vehicle. Classic air sprung models have a disable switch under the seat. On the 4.0/4.6, no such switch is provided, but leaving the tailgate open effectively freezes the suspension. It is wise to leave a door open as well, in case one or the other accidentally gets closed. For an extra measure of safety you can unplug the air suspension delay timer, a small black box that looks like a large relay under the left front seat (see photo at right). On the 4.0/4.6, removing Fuse 44 or 17 should also work

Air Spring Replacement:
Although air spring replacement on the 4.0/4.6 is very similar to the Classic models, there are a few  differences, including how to disable the air suspension, access to the parts, and in the type of clips used to hold the top and bottom pieces of the air springs in place. (Note: there are very good illustrated instructions for the operation on the Arnott website.
http://arnottindustries.com/manuals/index.asp).
Remember to disable the air suspension first, at least by opening the rear hatch and a door, or other methods described under "Disabling the Air Suspension" above. Regarding the fastenings, the 4.0/4.6 models use "R" shaped pin/clips on the rear, rather than the spring clips used on the Classic and on the front of the 4.0/4.6. Also note that the official shop manual requires removal of the plastic wheel well liners; this is not really necessary, and in the case of the rear springs, barely improves access at all.
Gaining Access to the Top Spring Clips:
The workshop manual tells you to remove the rear inner wheel well liners; this is not necessary and unlike the front springs, makes hardly any difference to access (only a couple millimeters more room where the plastic liner hangs down).  If for some reason your liner hangs down more than a few millimeters it is easier to make a small cut in the liner than to remove the entire thing.  Nor do you even have to remove the wheels. Tools: I suggests one pair of long needle nose pliers to pull the retaining pin, one 6-8" long flat screwdriver to depress the air hose collect, floor jack(s).  Two jack stands, an optional mini LED light (photo at right) to see into the little gap between the wheel well liner and the frame where the "R" pin and air line are located.  Beware adverse climates may have corroded them, and you might need a 8-12" metal hook to "hook" the end of the top "R" pin and yank it out, and a hammer to pound out the bottom "R" pin.



Rear air-spring Removal Procedure:

 1. Pull the bottom "R" shaped pins to release the bottom of the air spring.

2. Lift the car fairly high on both sides and support it on stands under the frame just forward of the rear wheels. Ron used a jack on each side of the rear axle, then put chassis stands under the chassis. This is because you will need to hold the body up whilst lowering the axle to fit the air spring. Ron found it beneficial to use two jacks so you can lower the axle evenly (he used two trolley jacks).

3. With the suspension hanging, disconnect the air line at the top,  pull the top pin or "R clip" (see photo on the right) and it's dead easy to pull the spring out. (Some owners have found the spring is corroded in place and is harder to pull out; of this is the case brute force may be required -- there are no other attachments to worry about other than the two pins you have removed). Ron and I were both able to access everything without removing the rear wheels. If you live in an area where corrosion is a problem, getting the pins out may be harder, and require removal of the wheel arch liner for better access.

4. Fit new spring and reinsert top retaining pin. Fit air line - just push it in.  Jack up axle evenly on each side until the bottom spring plate enters the hole in the axle. If you don't raise the axle evenly a bag can easily pop off the piston. This happened to Ron but he found it was easy to refit -- he lubed the piston with a bit of kitchen washing up detergent and it popped straight on.

5. Fit bottom clips.  Do other side, remove chassis stands and lower the vehicle.

1. Open the hatch and at least one more door to deactivate the air suspension (the hatch is good because when you jack up one side a door can close by itself).
2. Pull the bottom "R" shaped pins to release the bottom of the air spring.
3. Put the floor jack under the frame and lift until you can see the air line with your flashlight above the tire.
4. Hold the air line in one hand and press the metal collar with the screwdriver to let the air out (wear glasses so escaping air can't blow anything into your eyes).
5. Pull out the air line and put a piece over the top of it.
6. Pull the top "R shaped pin"  and the spring will drop out (you may have to wiggle it a little bit).
7. Install the new air spring (the mini LED light lets you see what is going on). First put in the top "R" pin in then slide in the air line.
8. Lower the frame until the bottom of the spring goes in to the hole and slide in the bottom "R" spring and you are done.
Front air-spring Removal Procedure: 
1.Remove Air Spring Top Clips:

The plastic fender liners inhibit access to the two metal clips that connect the top of the air springs to the body. With the liners in place,I found it very difficult to "lift and push" the clips at the same time by reaching down with a standard flat blade screwdriver. So, I ended up pulling the inner fender liner for easier access. If you do this, it is a good idea to buy a couple of the two-piece fender liner retainers as spares, since it is easy to damage them. Similarly with the spring top clips, a couple spare clips are handy in case you break or lose one.
Remove Bottom Pin and Spring:
The bottom of the front spring is secured by a long metal pin that is bolted to the axle. After removing the bolt (13 mm socket) you can pull the metal pin out of the bottom of the spring. Then, with the top clips off and the bottom pin out you can maneuver the old spring out if you raise the chassis or lower the axle sufficiently.

The spring should come out easily, but if yours doesn't, because of salt on the roads causing corrosion, for example, don't hesitate to apply brute force, as there are no other fixings than the top clips and the bottom pin you have already removed.

Installing the New Spring
 Set the new spring in place, slide the bottom pin in and connected the bottom pin bolt to the axle. Then lowered the frame (I raised the axle instead) until the studs on the top of the air spring went in the holes and the top clips cold be put back on.  Then he replaced the inner fender and pushed the air line in to the new spring. The shop manual says "! CAUTION: When refitting the air spring, do not allow the vehicle to rest on the deflated air spring. The chassis must be supported until the air spring is inflated". So, with the axle still on the stand and the frame still on the jack to prevent the vehicle from sitting on the bump stop, he closed the doors and the hatch and started the engine and watched the new spring fill with air. After checking for leaks he put the wheel back on and lowered the vehicle to the ground.
Start the engine (doors and tailgate closed to allow the E.A.S to work) and check that the car rises.

Land Rover air suspension" Problems and solutions" 1995-2002

I have been a land Rover enthusiast and owner for over 10 years and in my time I have visited the dealer once.
Never again would I be fooled into a temporary solution to the planned obsolescence of these vehicles again.
My first and last trip was $expensive$ and the problem reoccurred 2 weeks later not the same spot but the same problem. I had an air leak in the E.A.S "Electronic air suspension" system that was causing my Air compressor pump to overheat eventually leading to pump failure. The dealer had the truck almost 4 weeks before I got it back and at a grand total over $2000.00.  Furious and confused I was off to the net to find a solution. To view an image just click on it to see in full size!!
Here is some useful info I found and interpreted for easy digestion

The Electronic Air suspension System is comprised of 11 key components:
1. Electrical control unit   
2. Compressor
3. Air dryer
4. Valve block
5. Reservoir Tank
6. Height sensors front
7. Height sensors rear
8. Front air springs
9. Rear air springs
10. Relays, fuses
11. Driver controls
Common E.A.S problems
The electronic air suspension system is controlled by an ECU or "electronic control unit" under the drivers  seat, This control unit operates a solenoid valve block in the engine compartment. The ECU has a flawed design and tends to waste a lot of air by raising and lowering each corner attempting to level the vehicle. So the pressure is used and the compressor runs frequently. Another cause of frequent running is the fact that the pressure switch is located remotely from the air tank so the pressure drop in the air line makes it think more air is needed. Another problem which is said to be normal occurs whenever the vehicle is parked on uneven terrain or surfaces. The air suspension system attempts to level itself by first lowering all the air-springs to the height of the lowest one of 4, then realizes it is still not level so it lowers the first spring as well and begins the whole cycle over again until the vehicle ends up on the bump stops. This very ingenious strategy gets to be   annoying when off road, Since terrain varies the ground is nearly always uneven. If you want to stop in such an area temporarily, leave the engine running, or inhibit the system's operation by leaving a door ajar or the tailgate open. Pressing the manual inhibit switch on the dash also helps reduce or eliminate this behaviour.
So whenever the air suspension has some issues switch to manual and inhibit the E.A.S from the Christmas tree control on the center of the dash as to keep from further compressor operation.
Last but not least, Regardless of whether you are on or off road, the ECU often lets too much air pressure out of the system overnight so when you come out in the morning it can take some time for the suspension to raise itself up again to normal height causing excessive compressor operation. This is not supposed to happen but often does, even though the suspension checks out normally on the dealer's T-4 test-book.


Proper Operation according to the Manufacturer:


Air springs provide a soft and comfortable feel to the
ride of the vehicle. The use of a microprocessor to
control the system exploits the advantages of air
suspension.
The system provides a near constant ride frequency
under all load conditions resulting in:
• Improved ride quality
• Consistency of ride quality
• Constant ride height
• Improved headlamp leveling

The system provides five ride height settings plus self
levelling. Each setting is automatically maintained at
the correct height by the system logic with the
minimum of driver involvement. Vehicle height is
sensed by four rotary potentiometer type height
sensors. Height information from each sensor signals
the electronic control unit (ECU) to adjust each air
spring by switching the solenoid valves to hold, add or
release air.
The five height settings are:
1.Standard profile:
2.Low profile: 25 mm (1 in.) below standard.
3.Access: 65 mm (2.6 in.) below standard. Crawl: It is
   possible to drive at the access ride height at speeds
   less than 32 km/h (20 mph)
4.High profile: 40 mm (1.6 in.) above standard.
5.Extended profile: 70 mm (2.75 in.) above standard.
This setting is not manually selectable.

Air is drawn through the inlet filter (1) to the
compressor (2), where it is compressed to 10 ± 0,5
bar (145 ± 7.25 lbf/irr').
Compressed air passes to the air dryer (3) where
moisture is removed as it flows through the dryer
desiccant. The desiccant in the lower portion of the
dryer becomes wet.
Dried air passes through a non-return valve NRV1 to
the reservoir (4).
The 3 non-return valves (6) ensure correct air flow.
They also prevent loss of spring pressure if total loss
of reservoir pressure occurs.
The pressure switch (5) maintains system pressure
between set limits by switching on and off the
compressor via an ECU controlled relay.

For air to be admitted to an air spring (10), the inlet
valve (7) must be energized together with the relevant
air spring solenoid valve (9).
For air to be exhausted from an air spring, the exhaust
valve (8) must be energized together with the relevant
air spring solenoid valve.
The solenoid diaphragm valve (12) ensures that all air
exhausted to atmosphere passes through the dryer.
Exhausted air passes vertically downwards through
the dryer. This action purges moisture from the
desiccant and regenerates the air dryer.
Air is finally exhausted through the system air
operated diaphragm valve (13) and to atmosphere
through a silencer (14) mounted below the valve
block.
Symptom - Hard Ride.

Symptom - Air Suspension System Faulty Or Inoperative.

Land Rover air suspension" Faults & diagnosis " 1995 - 2002 p38 model

"E.A.S FAULT" Message
The "E.A.S FAULT" message is displayed when any number of faults, such as the ones listed below, are detected by the system ECU. As well as the message, all the lights on the height adjustment rocker switch start flashing and eventually settle into staying on, along with the "high" ride height indicator light. There are two degrees of severity of this fault condition:
1. "Hard Fault": If the fault is considered serious, the system goes into what we long-suffering owners call "Hard Fault" mode. It is accompanied by the vehicle lowering itself to the bump stops and displaying the warning not to exceed 35 mph. Even if the cause of the fault is repaired, the hard fault condition cannot be reset without a visit to the dealer or other mechanic with the specialized T4/Test-book, Rovacom or Auto-logic test equipment. Most common causes are serious air leaks or compressor problems.
2. "Soft Fault": This is my own name for the less serious condition when the E.A.S FAULT message appears, accompanied by the Christmas tree lights on the dash, but not the the "25 MPH" warning. The suspension can no longer be moved from the current height, but will continue to run the compressor and make adjustments. In this case you are lucky; if the cause of the fault goes away, the fault clears itself when you switch off the engine for a while and restart it. In my experience and from other reports, The causes of this condition can include a bad E.A.S relay in the engine compartment fuse box, a bad ground somewhere in the E.A.S system, an intermittent electrical connection, or a faulty height sensor.


Frequent Compressor Operation:
Unfortunately this is usually normal. Suspect is the pressure switch being located on the valve block instead of at the tank. This causes the pressure switch to sense a drop in pressure every time air is drawn from the tank -- due to the long narrow gauge airline from tank to valve block. This momentary drop in pressure causes the compressor to come on again. If compressor operation becomes almost continuous, however, something is wrong
Continuous Compressor Operation:
The compressor should shut itself off when it gets hot or when pressure reaches 10 bar (150 psi), but if it seems to remain on too much the first thing to check for is the presence of leaks (see above), most likely from the air tank connection to the valve block. Then, see if either the air compressor relay (Relay 20, Engine Compartment Fuse Box) or the pressure switch is stuck on (see the Electrical Troubleshooting Manual for details). Otherwise, the compressor may be simply worn out -- this does happen. Starting from a completely depressurized tank, the compressor should take about 6 minutes to recharge it. If it stays on long enough to overheat, its thermal switch sends a signal to the ECU which shuts it down for 3 minutes to cool off. 
Frequent Short-Time Ineffective Compressor Operation:
If the pump runs with a short duty cycle, IE runs for a few seconds and stops, without effective pumping action, Its been reported that it is most likely the E.A.S ECU cutting off the pump's power supply die to excessive electrical draw. The computer diagnostic systems often miss this fault. If you pull the pump relay and jumper the 30/51 pin to the 87 pin, the pump will resume running if this is the problem. The most common cause is the failure of the pump's rear bearing. A shortcut for fixing this problem is listed on the Falconworks site, and consists of drilling the brush holder from the rear bell of the motor, so the bearing can be cleaned or replaced and lubed, preloaded and staked back in so it will not shake itself loose again. If you try this, the four brush-holder retainers will need to be drilled on-center and tapped to #4x40 threads. Be sure to touch-up the solder joints on the back of the brush holder that were cracked by the armature flailing around, then refit it with new 4-40 screws. Falconworks advertises the ability to repair your E.A.S pump in this situation for about $100, depending on the level of damage, plus shipping.
Slow Pump-Up after Leaving Overnight:
In theory, even if the unintelligent ECU has lowered the vehicle to the bump stops overnight, the non-return valves in the valve block should ensure that enough air remains in the tank to pump it up again immediately in the morning. If this does not happen, and it takes ages for the system to pump up to normal height in the morning, air is probably leaking from the line from the tank to the valve block (usually at the connection to the valve block). If not, the valves inside the valve block are probably leaking; as of this writing there is no known solution for this other than to replace the $800 valve block.
Noise or Vibration from the Compressor:
After a while the air suspension compressor can get rather noisy due to the rubber mounts wearing out. A Service Bulletin (TEC600695, July 1995, "Electronic Air Suspension Compressor Noisy") recommends updating the compressor mounts with  2 STC 828 Rubber Mounts and 6 STC 3086 snubbing washers. I had this done on my 4.0 and it did quieten down the compressor. The new bushing design is better because it prevents the compressor mounting flanges sagging low enough to hit the mounting surface. Loose mounting nuts, can also lead to noise. Conversely, don't over tighten the nuts as the studs are just embedded in plastic and come loose, again causing vibration. If the noise is a kind of harsh rattle, the compressor is probably worn out and needs replacing or rebuilding.
Compressor Failure:
Complete failure of the compressor could be due to the failure of Fuse 44, Maxi Fuse 2, or Relay 20, all located in the engine compartment fuse box. The easiest way to diagnose the power flow is to unplug relay 20, connect its output socket to 12V and see if the pump runs. If so, the compressor itself is clearly OK, but the problem could be the relay or one of the fuses, the thermal cutout switch, the pressure switch or the ECU. For more compressor diagnostic information see the Compressor Diagnosis and Replacement page.


 Intermittent compressor operation (or only operating for a small fraction of the time, resulting in very slow pump-up of the suspension) can be due to failure of its internal thermal cutout switch, which is designed to shut down the compressor when it gets too hot. In normal operation, the third lead on the compressor (which is internally connected to this switch) is grounded; when overheating, the switch opens. This happened on my 4.0SE; I was able to get the system going again by grounding this lead with a jumper. See the Compressor Diagnosis and Replacement page for more information, and the generic parts sources page for aftermarket replacement compressors.

 
Air Spring Leaks (Slow):
  Rubber air springs do wear out faster than the old coil springs. One symptom is the boot popping out of position, especially in cold weather; I had this happen on leaving the car outside in the desert overnight, in access mode, and the suspension took a good 10 minutes to return to normal height on startup in the morning. The rubber boot seems to mate with the top metal part of the spring somewhat like a tire bead, and will usually reseat itself after a while. One reader pressure tested an old air spring he replaced on his 95 LWB (see replacement procedure); he pumped 20 psi into it and put it into a bucket of water. Air seeped out from the top, between the metal and rubber joint. He tried a higher pressure and it sealed up (the pressure in actual use is up to 20 bar or 150 psi). Another problem is plain old cracks and holes developing in the rubber when it gets worn. This happened on one of my rear springs around 80,000 miles.  I was shocked that the system put up with this situation without shutting down and reverting to the "limp home" mode on the bump stops.

Air Spring Failure (Catastrophic):
Sudden failure of an air spring can occur due to spontaneous bursting or more likely being penetrated by some off road obstacle. If at high speeds the vehicle becomes unstable and can easily overturn.