EAS tank not holding pressure.

[PeterH]

Hi all, I've done a fair bit of work on my EAS over time (as we all have), most recently 3 new air bags, the fourth is only about 12 months old.
The compressor and valve block have been rebuilt about 12 months or so ago.
The car has been dropping over a few hours, the new air bags have improved that greatly.
My problem is the air tank seems to be losing pressure while parked.
I have checked and rechecked all hose connections, valve block, read and cleard any fault codes, can not find any leaks.
So my question is, if the tank is losing pressure, could it be the non return valves letting the pressure escape?
Or something else maybe? Any suggestions welcome.
I just want to investigate any possibilites before I take anything apart.
Cheers, Pete.

[davidsonsm]

If the NRV's are leaking, to symptom is usually the front end or the rear end dropping uniformly - that's been my experience.


You've got to have a leak somewhere. Can you get your hands on an ultrasonic leak detector?

[PeterH]

Thanks David, yes I agree it must be a leak somewhere...no I don't have acces to a leak detector, that would make life easier!
I had a friend with a Disco 2, the rear end just dropped one day while driving, sounds like what you describe with the nrv symptoms.
I'm wondering if the air hose from the tank on mine has developed a leak somewhere, I might try and get under with low tech soapy water and see if I can find anything.

[finallyrangie]

worth a second to check the drain bolt on the tank is tight to, hopefully it's something simple.

Good luck

[davidsonsm]

Have you tried leaving it at standard height, to see how it settles with the EAS timer delay relay disengaged. That could help diagnose whether the leak is one sided or NRV related. Pretty rare to hear of the tank leaking.

[finallyrangie]

I found a crack in the plastic body of one of my solenoids that was letting out just enough pressure to let it gently down, quick visual check but worth it to rule it out.

[PeterH]

I got under and sprayed soapy water on the air tank drain bolt, alas, no leak.
I'll disable the eas tonight and see what happens...would love to get this sorted!

[PeterH]

I have an update, I changed the eas relay under the passenger seat to a yellow one as described in another post, effectively disabling the eas while the vehicle is not running.
Since doing that, it has stayed up perfectly overnight at all four corners, which has been excellent.
I started it up this morning and found the tank must still be draining, it took exaclty 10 mins for the compressor to shut off with a door open.
So it appears the tank is completley draining overnight and I seem to have ruled out leaks in the airsprings or lines.
So, eas gurus, what should me next step be here?
Do I need to take the valve block out and inspect it?
If so, what should I be looking at here, any particular areas or valves I should be checking as the most likely culprit?
Any help here will be most appreciated!
Thanks, Pete.

[daf11e]

Pete have you checked for leaks with the air dryer?

[PeterH]

Yep, sprayed soapy water on the top and bottom connections of the air dryer, did not see any bubbles forming.

[daf11e]

If all external points aren't leaking I would assume valve block internals...NRV or diaphragm maybe. Also have you checked for leaks at compressor fittings?
I have read also of slow leaks between the valve block square components themselves...I think the valve block is made up of three.

[PeterH]

Have also checked the compressor fittings with no leaks.
I rebuilt the compressor and valve block about a year ago, so I'd say the diaphragm would be ok, but I am suspecting a problem with the nrv's.
Looks like I'll be taking out the valve block soon!
Would be nice to have it all working properly again.
Thanks for your suggestions.
Cheers, Pete.

[finallyrangie]

from the sound of it I think you may be right about it being non return valves, pain to have to take it all back out again, keep reminding yourself it will all be worth it when it's working.

let us know how it goes and good luck, after all this you have earned a break!

[davidsonsm]

Have you tried ziplocking a rubber balloon over the exhaust? If it fills, it helps to understand the air flow path out of the system.

[daf11e]

If it's leaking through the exhaust valve wouldn't that indicate a diaphragm issue?

[PaulP38a]

My money is on the "red" NRV and possibly the Diaphragm Valve leaking in the following schematic http://paulp38a.com/wp-content/uploads/2014/04/EAS-ValveBlock-v1.6-Inflate-LF.jpg

If the car stays up with the EAS Timer removed or door/tailgate open, but tank pressure drops, then solenoids for air springs and inlet should be ok. exhaust solenoid might still have a problem though.

This schematic is part of an article that might be useful in troubleshooting How EAS Works | PaulP38A.com (http://paulp38a.com/range-rover-p38/how-eas-works/)

Hope this helps to narrow down the problem.

Cheers, Paul.

[PeterH]

Thanks Paul, that was exactly the point in the right direction I was hopping for.
I had the same thought about the air spring and inlet solenoids probably being ok.
I pulled the valve block out yesterday to give it a mini check over, in particular the diaphragm and the nrv's.
The diaphragm looked ok, (it's only about 2 years old), but when I took off the block that holds the nrv's, I discovered the middle valve had fallen apart, (see attached pic).
No wonder I was having troubles!
I had to retreive the stem from inside the block with a pair of tweezers.
Fortunately I have a spare valve block on hand, so I was able to replace the damaged valve, (yes definitely in the correct direction!).
Got it all back together and I noticed the compressor seems to be running very often, then it shuts off and the valve block makes those levelling click noises, I can see the front of the vehicle lower slightly, then the compressor kicks in again after about 30 seconds and the cycle begins again.
Sounds like the slow dance I have experienced before, only it's doing it while idling and no foot on the brake.
Maybe I need to replace all the nrv seals to be sure it's not that?
I'm not sure what to do from here.

[daf11e]

Peter when I rebuilt my valve block last time I had the same dancing and it turned out to be a pinched o ring . I found it on the EAS software the fault came up Right Front and sure enough o ring.
Mine was coming down and dancing RFront first.
Does your front come down evenly both sides?

[PeterH]

Yes it appears to be even both sides, the slow dance it is!
When you say you had a pinched o ring, do you remember which o ring it was?
That will help me to know what to suspect first.
I'm thinking I need to redo all the nrv's, I could be wrong though!
Cheers, Pete.

[daf11e]

I am pretty sure mine was in the front right solenoid hence that side going down first....the tic tic tic....then compressor ....again and again.

When I opened it and took the top off it was the centre o ring pinched.

PS. Both together does sound like NRVs though.

[Hoges]

Hi Peter,
in the photo in your post above, there's what seems to be whitish powder ...is it from the air dryer? If so, it may be collecting around some of the O-rings and causing leaks. It's worthwhile opening up the air dryer occasionally and tipping the desiccant into a large strainer to get rid of the "fines". You then "bake" the large particles at 90 deg C on a flat tray for a couple of hours in the kitchen fan-forced electric oven (not gas---you don't want water vapour around) to drive off the water and regenerate the desiccant. Wait for the oven to cool near enough to room temp and then replace the desiccant in the air dryer making sure that the filter paper and spring are properly installed... (reassure SWMBO it's all in the name of science):angel::wasntme:

[PeterH]

Nice one Hoges! I'll check that out for sure.
Is the dessicant something that can be replaced for new, or is the oven baking method fine?
I can't say I've ever seen the dessicant as an available part.
Any tips on getting into the dryer, does the top just screw off or is there more to it?
I'll have to pull the valve block apart to check everything over properly by the looks of things.
I'll do the dessicant bake as well.
Will keep you posted.
Thanks, Pete.

[daf11e]

Pete there's one bolt holding it in 8ml I think....remove air lines and remove...the top screws off and could be a bit firm as IIRC there is a spring inside....good luck.

[p38arover]

Pete there's one bolt holding it in 8ml I think....remove air lines and remove...the top screws off and could be a bit firm as IIRC there is a spring inside....good luck.

10mm socket required. The lid is a bit tight. I did mine yesterday. I held the body in a vice so I could get a good grip on the lid. I'm about to go out and reassemble it after having it in the oven after my wife cooked dinner in there.

[daf11e]

There's the spring and the metal inside is the cover.

[p38arover]

That saves me having to take pics! :D

What I did notice was that the filter material under the top screen on mine was twisted up and not fully covering the screen. It may have let dust through into the system. I've never had it apart before.

[PeterH]

Thank you all for the advice, certainly makes life easier!
I'll get on it as soon as I can.
Cheers, Pete.

[PeterH]

I got the cannister out and did the baking trick, Martha Stewart would be proud!
Also pulled ou the valve block again and checked for any obvious o ring problems, but could not find any.
Checked the diaphragm and non return valves, as far as I can tell, it all looks ok.
Got it back together and it is still doing the slow dance, only a bit worse now, compressor runs for a few mins, shuts off, immediatley the valve block ticks and lets the front of the car down, compressor kicks in again and it keeps cycling like that.
What is my next step here, do I need new non return valves or o rings for the nrv's?

I also noticed air escaping from the valve block exhaust while the car is switched off.
Does not seem to do it while running.
Would this indicate a diaphragm issue?
I would love to get this sorted!
Cheers, Pete.

[daf11e]

Pete I am pretty sure if air is escaping while off you have a diaphragm issue.
The diaphragm may look ok but it may still be u/s.

[Hoges]

Pete I am pretty sure if air is escaping while off you have a diaphragm issue.
The diaphragm may look ok but it may still be u/s.

yep, what he said;)

[Hoges]

Nice one Hoges! I'll check that out for sure.
Is the dessicant something that can be replaced for new, or is the oven baking method fine?
I can't say I've ever seen the dessicant as an available part.
Any tips on getting into the dryer, does the top just screw off or is there more to it?
I'll have to pull the valve block apart to check everything over properly by the looks of things.
I'll do the dessicant bake as well.
Will keep you posted.
Thanks, Pete.

My ol' chemistry professor would be (almost) pleased:D except that it is spelt desiccant ... small spelling slip cost me dearly 47yrs ago...you'd think I'd have got over it...ah well those were the days when English grammar was taught properly ...and generally "I done good" :eek: :wasntme:

Anyway apart from that small digression... yep, perfectly OK to regenerate it in the oven... you can do it countless times until you need to buy more because of the gradual attrition from it powdering. If the spring and filter paper are in good nick then the stuff shouldn't jump around too much. It's the constant engine vibration I suspect which largely contributes to the large particles gradually disintegrating.

[PeterH]

Ok, I'll be ordering a new diaphragm tonight.
What do you gents think about the nrv slow dance problem?
Maybe I should replace the nrv o rings too, or is there another cure for that?
Cheers, Pete.

[daf11e]

Pete I would start with rechecking nrv's and valve block in general.....if the valve block is 100% ok then there are I believe two other possibilities...
Height sensor
Driver pack.
From what I have read the driver is not very common but does fail.
I am sure others will chime in if I am wrong. If you get to the stage of wanting to check the driver I believe their not cheap and I do have a spare you can try if you want.
Just re read your thread and yes if you havnt replaced the o rings in the NRVs then that's first.

[Hoges]

The back of the driver pack is sealed with resin material. If the resin surface looks like heat-shocked chocolate and the driver pack is original, then it's likely the pack is on the way out...

[PeterH]

Hoges, that is an excellent descripton, it does look like heat shocked chocolate, yes it would be the original driver pack.
I have ordered a complete o ring kit, including diaphragm, once that arrives the block will be coming out once again to do the nrv's and diaphragm.
On the up side, after pulling out the valve block a few times, you get really fast at it!

I disabled the eas last night and the rear has stayed up fine, I can see the front has dropped slightly, the tank has no pressure.

I've also read the height sensors can be swapped from side to side, can this be done on a 2001 HSE?
So I'll do the o rings first, if no joy I'll swap or replace the height sensors, after that will be the driver pack.
Thanks for all the help everyone, I'd be on the bump stops without it!
Cheers, Pete.

[p38arover]

If you swap the height sensors, you will need to recalibrate the heights with Testbook, Nanocom, or Faultmate, et al.

[Hoges]

Sensors can indeed be swapped on the 2001 model. Re. calibration, include in Ron's list under "et al" Story Wilson's free EAS software which does a very good job on this score

[daf11e]

I swapped my front height sensors no worries when I was having FR dancing issues.....nothing changed ruling out the sensors, that's when I found the pinched o ring in FR solenoid......it's a good way to eliminate sensors.

[PeterH]

OK, failing the o rings and diaphragm, sensors will be getting swapped!
I already have the eas unlock software and my own home made calibration blocks, so re calibration is not a problem.
I suspect the rest of the valve block is fine, it holds up fine overnight with the eas disabled, even though the tank is still draining.
I'll be on it as soon as the o rings arrive.
Cheers, Pete.

[p38arover]

Inside the valve driver block. Sorry about poor quality, I'll take better one later. It took me quite some time to dig out the tpoxy.

Edit: I found a better one that I had annotated.

https://www.aulro.com/afvb/images/imported/2015/05/204.jpg