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1995-2002 Range Rover P38A
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Discussion Starter #1
Hi

It has been a long time since I posted a question here :)

My EAS has been overhauled (some time ago now) by me and I have done these overhauls before. The valve block has new o-rings etc and I installed 4 new airbags and the compressor was given "a birthday".

After the overhaul, the rear LHS would drop almost to the bump stops within 6-8 hours. From a previous overhaul experience (on a different RR) where I inadvertently "pinched" a valve block o-ring and caused a leak, I assumed I had done something similar on my current RR to cause this "leak" or suspension drop.

In the short term as a quick fix, I disconnected ALL the airbag lines and used my "emergency kit" of schrader tyre valves to manually pump up the suspension. I also thought this would allow me to verify the air lines / airbag leakage. The whole system was fitted with new o-rings (and the new air bags), so in theory the leaks should be minimal.

So, the problem seems to be within the rear LHS air line or air bag. Most of the time this rear LHS corner drops within two days and sometimes overnight. HOWEVER sometimes when I pump it up the (supposedly leaky) rear LHS stays up for at least TWO weeks (while the other corners slowly drop). REMEMBER this is under full "MANUAL" control (with my workshop compressor providing the airbag inflation), there is NO interaction with the valve block or EAS electronics. ALL air lines from the valve block to the airbags are completely disconnected.

This status is random(?) as most times the rear LHS does drop but after inflating the bag it just MAY retain its pressure for this extended time frame.

This to me, seems to indicate a "sweet spot" where the air bag and piston are just at the right location to form a REALLY GOOD seal. Either side of this sweet spot, the seal is not so good and the pressure drops. I cannot duplicate the situation on demand (though I have not tried to adjust the height by monitoring the air bag pressure to find the sweet spot). BTW the potential "sweet spot" is not at full height where the airbag is pressed up against the larger part of the piston. It "happens" at about the standard ride height.

Has anyone else experienced this or something very similar?

I have contemplated using o-ring lubricant on the airbag pistons and deflating/inflating the airbags to try and improve the "seal" between them, then wiping off any excess lubricant to ensure that dirt/grit does not stick to the piston body.
 

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1995-2002 Range Rover P38A
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What airbags are you using? It does not sound like the newer kind with a metal band that seals the upper and lower bladder. I don't think I would mess with the lube yet. The problem is to get a good test you need them at pressure and under load which is tough to do when they are off the vehicle. Have you done a soapy water test on them at various ride heights? Take the wheel off and use a stand so you can get full access to the bag. Run it through its paces and soak it carefully and look closely to see what happens. You can take the bag off and inspect it to see around the seal area, could be some contamination. I have taken bags off and pressurized them and held them in a tub to look for leaks. The problem is you cannot easily cycle them to simulate ride heights. If you use low enough pressure to do that, you probably won't get leaks.

You can also swap bags left to right and see if the problem travels with the bag.
 

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1995-2002 Range Rover P38A
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336 Posts
Discussion Starter #3
Thank you for the reply. I am reasonably sure the problem is with the airbag, as this is really the only variable (well apart from the air pressure). The o-ring at the air line connection remains the same of course. If could duplicate the problem on demand I "could" swap the bags side to side, but this is too much effort for no real gain/proof of the fault. The airbags are Dunlop replacements a "whole" units, not just the bladders.

If I really have to, I could make up a welded steel frame to allow testing under pressure at different "heights".

In the next few days, I'll investigate for potential leaks and see what I find.
 

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1995-2002 Range Rover P38A
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343 Posts
Just a sidenote: you talk about 'the O ring at the airline connection', Original Dunlops come with two O rings per bag, I know one aftermarket supplier that has cheap copy-Dunlops that come with just one ring, guaranteed they tend to leak.
 

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1995-2002 Range Rover P38A
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336 Posts
Discussion Starter #5
Hi

Thank you for the note. I'm sure there are two o-rings in the connection, but I will now double check that just in case :)
 

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Also check the end of the airline has a smooth chamfer. Doesn't always happen, but sharp edges on the airline can damage the o-ring when inserted into the airbag.
 

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1995-2002 Range Rover P38A
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Discussion Starter #7
thank you...:)
 

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1995-2002 Range Rover P38A
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336 Posts
Discussion Starter #8
A quick update. The problem was a faulty push on airline connector. While I set the RR in "manual mode" using schrader valves on all the airlines removed from the valve block, I would inflate the EAS using a compressor. If the faulty valve was not in the "right spot" it would leak. Sometimes after inflation it would be in the right spot and would not leak. Holding it at a slight angle allowed the air to leak.
 

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1995-2002 Range Rover Classic
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1,413 Posts
I use arnott gen 2 and still leak, it is inherent of the rubber. it will leak/ seep. currently in my area the weather is changing were going into the fall. cool nights (50 degrees F) and warm days (75 F) make both of my trucks drop to bump stops before midnight even with 2 yr old bags, one fitted with factory style the other with arnotts.
in retrospect they stay up off the bumps 24/7 for nearly 2 weeks during the summer at 80 plus temps.

there is always a weak link. the land rover tradition ...
 
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