Common Air Leaks P-38 Range Rover
Air leaks are the #1 enemy of your air suspension system.
The front Air Springs can come loose from the top mounting. The seal can easily be broken when the wheels have been allowed to hang down without disabling the air suspension system. This can be an intermittent leak when stationary as the weight of your Range Rover will tend to re-seal them, but when driving the combination of movement and heat will allow air to escape. Note: The new style Air Spring has a stainless steel band around the top and I have not had one of these leak – so far.
Front and rear Air Springs have had leaking 'O' Ring seals at the Air Pipe connection and the Air Springs can develop small age cracks that the air bleeds out through. (8 to 10 years seems to be a good age for the Air Springs to develop these small cracks (around Sydney), even earlier if your Range Rover has been used in hot climates.) Replace the Air Springs when the small cracks appear. (After market rubber bellows are available separately.)
The Valve Block has been known to leak from the 'O' Ring Seals for the Air Pipes, from under the Solenoid covers, and internally. Replace the Valve Block. (Reconditioned Valve Blocks may be available from your repairer – quality???)
A leaking Engine Exhaust Pipe Flange over the top of the of the rear axle directs the hot exhaust gasses on to the three Air Pipes located on top of the chassis and melts them. (Air Pipe joiners are available.)
A Battery Acid spill in a Range Rover will eat away the Air Pipe under the battery tray going to the RH front Air Spring.
Air Tank leaks have been found at the 'O' Ring seals for the Air Pipe and at the threaded connections.
It is strongly recommended that your Range Rover be thoroughly checked for air leaks regularly and before you depart for the Outback. The extra work the Compressor and the Valve Block have to do to keep up with air leaks only shortens the working life of both and costs you money.
The job of the dryer is to absorb moisture from the incoming compressed air and hold this moisture until air is expelled at which time the trapped moisture is blown out and the dryer media is recharged. With air leak(s) the incoming moisture builds up in the dryer media as there is more air coming in than being expelled. When the dryer media is saturated it breaks down into a white powder that is blown throughout the system. This plays havoc inside of the Valve Block with valves no longer sealing causing internal leaks, failure of the Air Operated Solenoid Diaphragm and clogged exhaust silencer.
Remember - Air leaks are the #1 enemy of your air suspension system. Stop the leaks and save $$$$
Finding air leaks
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 water solution so that when it is sprayed on an air leak it will bubble and expose where the leak is. I use and recommend diluted Morning Fresh dishwashing liquid - it really is just great at making bubbles.
Start the engine and raise your Range Rover to the highest height setting. When the high setting is reached open a door/tailgate 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 Solenoids that are on top.
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/damaged 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 resistance is normal). Dryer Media in the exhaust port requires a new Dryer, Air Pipe flush and Valve Block flush or in bad cases a replacement Valve Block.
* Classic Range Rovers have an Air Pipe that has to be removed from the Exhaust Port. Thoroughly clean the area and push the Collet in against the Valve Block body and hold it there while wiggling and pulling out the Air Pipe.
Do not attempt to stop leaking air from escaping out of the Exhaust Port.
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.
Looking for leaking 'O' Rings at the Air Pipes. Spray the top fittings of the front Air Springs. Spray the top fittings of the rear Air Springs - from over the top of the tyres.
When the Air Tank is full and the Compressor automatically stops close any open doors/tailgate and put the suspension to Standard height. This is where your suspension is most of the time and where most of the wear on the Air Springs 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. Classic Range Rover - 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 on the tape and write the height measurement.
Drive your Range Rover for 10 to 20 minutes to get the Air Springs hot and release air from the top of the front Air Springs 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 Springs 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. A slight rise in height is acceptable as the air in the Air Springs expands with the heat generated during driving.
Use the spray bottle to check for leaks at the Air Springs. Spray the front Air Springs into the crack between the top Mounting Bracket and the Air Spring.
Spray both the front and rear Air Springs looking for air leaks. Spray the top Air Pipe fittings on the front Air Spring mountings for leaking 'O' Rings. When the rubber of the Air Spring bellows has perished small cracks or splits appear in the rubber. Air will be leaking out of these cracks when the Air Springs 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. Land Rover says that 20 mm (3/4 inch) is the maximum drop in 24 hours. A drop will usually indicate an external air leak and a height increase usually indicates a Valve Block that is leaking internally.
Use the spray to find the leak. If you cannot find a leak in the Air Spring or Air Pipe suspect the Valve Block. 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. It does go in at a slight angle - 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 less than 10 minutes.
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.
You have done the hard diagnostic work when you have found and noted your air leaks. You then have to decide what to do about them.
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.