This process is, at best, a half-day exercise. Read these instructions through first and then follow them.
You will need a spray bottle with a soapy solution so that when it is sprayed on an air leak it will bubble and expose where the leak is. Diluted Morning Fresh dishwashing liquid is just great.
Start the engine and raise your Range Rover to the High setting. When the High setting is reached open a door to prevent any further height changes.
While the Compressor is running use the spray bottle to check for leaks in the EAS-Box. Spray around the bases of the black Solenoid Valve covers that are accessible. Un-screw the Silencer* from the Exhaust Port, wet your finger with soapy water and gently place it over the opening. If you get a steady flow of air out of the Exhaust Port you have a split Diaphragm in the Air Operated Solenoid Valve. (Replacement diaphragm kits are available.) Check the inside of the silencer (Air Pipe) for a white powder residue (Dryer Media) and with your mouth blow air through the silencer to check for a blockage (some resestance is normal). Dryer Media in the exhaust port requires a new Dryer, Air Pipe flush and Valve Block replacement.
* Classic Range Rovers have an Air Pipe that has to be removed from the Exhaust Port. Thouroughly clean the area and push the Collet in against the Valve Block body and hold it there while pulling out the Air Pipe.
Just before the Compressor stops running you can hear and see it working at it's hardest pumping the Air Tank to 10 bar (150 psi). Spray the blue Compressor Air Pipe, the Dryer, the Solenoid Valves again and the Air Pipes on the side of the Valve Block while the Compressor is working at its hardest.
Spray the top fittings of the rear Air Bags - from over the top of the tyres. Looking for leaking 'O' Rings at the Air Pipes.
When the Air Tank is full and the Compressor stops automatically close any open doors and put the suspension in Standard height. This is where your suspension is most of the time and where most of the wear on the Air Bags takes place. When the suspension has settled at Standard height and the Compressor stops automatically after re-filling the Air Tank - stop the engine and open a door to prevent any further height changes.
Disable your Range Rover EAS - unplug the delay relay from under the left front seat.
Disable your Classic Range Rover EAS - use the disable switch located at the rear under the RH front seat.
Put a piece of masking tape at the top of each wheel arch. Measure the height from the bottom edge of the wheel rim, place a mark and write the height measurement on the masking tape at each wheel arch.
Drive your Range Rover for 10 to 20 minutes to get the Air Bags hot and release air from the top of the front Air Bags if they are leaking. If there is a leak at the upper mounting the front may drop while you are driving. If you need to refill the front or rear Air Bags to get back, stop in a safe place and enable your EAS.
Park your Range Rover (at Standard height) on a level surface where you have access to the under side to check for air leaks. (Disable your EAS again if you enabled it during your drive.)
Measure the corner heights again. If there are no leaks a slight rise in height is acceptable as the air in the Air Bags expands with the heat generated during driving.
Use the spray bottle to check for leaks at the Air Bags. Spray the front Air Bags into the crack between the top Mounting Bracket and the Air Bag.
Spray both the front and rear Air Bags looking for air leaks. Spray the top Air Pipe fittings on the front Air Bag mountings for leaking 'O' Rings. When the rubber of the Air Bag bellows has perished small cracks or splits appear in the rubber. Air will be leaking out of these cracks when the Air Bags are hot and flexing - replace the bellows.
Spray all of the Air Tank fittings.
Leave your Range Rover for half a day and check the corner heights. 20 mm (3/4 inch) is the maximum drop in 24 hours. A drop will indicate an external air leak and a height increase indicates a Valve Block that is leaking internally. (Replace the Valve Block.)
Use the spray to find the leak. If you cannot find a leak in the Air Bag or Air Pipe suspect the Valve Block. (Reconditioned ones are available.) Your repairer can undertake further diagnosis or you can try this yourself. Wet your finger with soapy water and gently place it over the Exhaust Port opening. If you get a single puff or a steady flow of air out of the Exhaust Port you have an internal leak.
Range Rovers - Carefully refit the Silencer to the Exhaust Port - do not cross thread it.
Classic Range Rovers - Just push the clean Air Pipe all the way back in to the Exhaust Port and it should seal itself.
Check the Air Tank for leaks by first opening a door to prevent height changes and refitting the Delay Relay. Start the engine and see if the Compressor runs or not. If the Air Tank has not lost much air the Pressure Switch will not turn the Compressor on. If the Compressor does run there is a leak - a short run time means that you have only lost a little air. A good Compressor (and no leaks) will fill an empty Air Tank in under 10 minutes.
You have done the hard work when you have found and noted your air leaks. You then have to decide what to do about them.
You can replace some leaking O-Ring seals. Using ROVAIR you can depressurise the part of the system where the leak is and replace the leaking O-Rings. (Available from your repairer.) Take care not to break the Collet or scratch the housing. ROVAIR PLUS has the repair instructions and spare O-Rings.
Major component replacement can be dangerous in many different ways. Numerous safety precautions must be observed to prevent injury to yourself and possible damage to your Range Rover. Unless you have the equipment and knowledge to safely carry out the repairs perhaps it is best left to your repairer to replace major components.
When your Range Rover, with the EAS disabled, does not drop overnight and the compressor does not have to refill the air tank in the morning you have no major air leaks.