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Leaking bladder


Les Henson
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I have to replace the air suspension pump an a Rangy next week. The sytem also has a leak somewhere which causes the vehicle to deflate overnight. Is there a particular method to detecting where the leak might be. Also I understand that if you drop the suspension too far to replace a bladder - it doesn't self-inflate after the job is done. Is there a trick to replacing the bladder without this happening?

Les.

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I have to replace the air suspension pump an a Rangy next week. The sytem also has a leak somewhere which causes the vehicle to deflate overnight. Is there a particular method to detecting where the leak might be. Also I understand that if you drop the suspension too far to replace a bladder - it doesn't self-inflate after the job is done. Is there a trick to replacing the bladder without this happening?

Les.

Steve.G's your man for this! I believe he's had similar continence problems in the past ;)

Si

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Which RR Les?

Leaks are normally at junction box of compressor, normally O-rings there, in piping especially where it comes close to exhaust on P38, or at bladder. A spray with soapy water helps trace pipe or O-ring leaks. The bladders can be hard to detect as they can leak only at certain heights. Normally down to rubber perishing and splitting.

If it's a p38, have the owner set the man switch on before they turn off ignition. Then in the morning it will either be all down, which means you have a leak in junction box (or all four corners are leaking! ;);) ) or usually it will be down in one corner.

For changing out the bladder - Disable air suspension by leaving drivers door open or tailgate open. Quick way is to put a jack under chassis in the corner you want to change. You can then simply yank the bladder off by grabbing at the top and pulling at an angle. It will come off with a loud bang! ;) . Clean up air springs mounts and replace with new bladder. Some washing up liquid on mounts may help if it's troublesome to put on.

If you don't like loud bangs you can decompress system by undoing release valve on tank.

Longer way is to remove spring completely by taking off air line at spring, remove R-clips and then take air spring out as a whole unit. Place mounts carefully in a vice a pull bladder off. You can carefully use a screwdriver to prise it off, but be careful not to damage lip. Again, clean up mounts, put bladder on and put back whole spring.

A good compressor will take 5-7min to completely recharge a system, any longer and you have a leak or compressor issue.

Cheers

Steve

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Les,

Be aware that the system operating correctly, with the vehicle parked will self level every 6 hours to the height of the lowest point by letting air out only (it does not inflate at all). My rangie pretty much ends up on the bumpstops after about 2 days because of this.

Try letting the vehicle level, then hit the disable switch under the drivers seat before switching the engine off. Then leave it overnight and see which corner(s) have gone down.

Soapy water is the best bet for leaks, but dear i mind the leak could also be within the valve block (ie one of the air valves is leaking).

Hth

Jon

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Soapy water, you will probably find that the leak is where the air spring rolls back inside itself when the vehicle is at "normal" ride height from the ones I have seen.

Also check for chafed pipes to the springs as that can cause much the same problem!

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Also I understand that if you drop the suspension too far to replace a bladder - it doesn't self-inflate after the job is done. Is there a trick to replacing the bladder without this happening?

Not heard of that before, and can't see why that would be the case? What you can do if you drop the suspension too far is turn the sensor arm inside out, which if you don't spot it before you turn the EAS ECU back on will cause it to throw a sensor out range error and refuse to play again until it's had counselling from a testbook.

If you don't like loud bangs you can decompress system by undoing release valve on tank.

You can also jumper the EAS ECU connector to deflate the relevant spring which is easy and safer.

Try letting the vehicle level, then hit the disable switch under the drivers seat before switching the engine off. Then leave it overnight and see which corner(s) have gone down.

The disable switch is only present on classics - if it's a P38a then setting it to manual may do the same thing (I don't know), else you can pull a fuse or leave a door open. Lots of info particularly for the P38a on www.rangerovers.net. Disconnecting the ECU plug will definitely work on both vehicles, and give you access to the connectors so you can manually control all parts of the system (it just switches 12V lines, so with a pinout and a bit of wire you can do the same).

A word of warning, though - never rely on these methods if you're working under the the car. Always assume it's going to decide to lower itself and support the chassis on axle stands.

I wrote a tech archive article on doing this job on a classic (P38a will be much the same). However, if you're doing this on a customer's car do your sums first - changing bladders is fairly straightforward but changing the complete spring unit is really simple, and they aren't that expensive now so it may well make more sense than putting in the labour.

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and refuse to play again until it's had counselling from a testbook.

Unless its mine which even with a new ECU still flatly refuses to talk to testbook!

It works fine apart from the fact that it doesnt sit level so I'm just ignoring it at the moment!

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Unless its mine which even with a new ECU still flatly refuses to talk to testbook!

It works fine apart from the fact that it doesnt sit level so I'm just ignoring it at the moment!

You could wire another potentiometer in series with each height sensor and then manually adjust the calibration :) You'd only be able to adjust in one direction but you could at least level it, and it'd be easy and dirt cheap to do. Guess if you got hold of some high resistance ones you might be able to get adjustment in the other direction by wiring them in parallel with the sensors.

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The disable switch is only present on classics - if it's a P38a then setting it to manual may do the same thing (I don't know), else you can pull a fuse or leave a door open.

When I had my P38 it would still 'settle' if left set to manual, the only way to stop it settling was to leave the tailgate or a door open.

I had a problem with it dropping down at the ROS and it just turned out to be the relevant bladder not seating properly.

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Just to add another twist to the tale - the new compressor is fitted wothout anything else on the system being touched and although the new pump runs, the suspension isn't being inflated. It seems to be in access mode all the time and any air pumped by the compressor is immediately going back out. This fault was intermittent before, and sometimes the suspension would be fine for a few days and then go down overnight. When you let the suspension down, where is the air in the system released?

Les.

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Les,

Have you got any warning lights showing? If you have then this is normal as it requires a reset via testbook.

The air is released to atmosphere via a valve in the valve block. Only other possiblity is a sticky valve or valaves in the valve block.

Cheers

Jon

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