P38A EAS dropping at rear

So after fitting my "EAS Disable" relay a few years ago, I've always had the rear rising while parked. Not a major issue so accepted it, with the plan to refurb the valve block at some point.

Now suddenly the rear has started dropping overnight. No signs of leaks at the valve block or air-bags with soapy water check, so I thought time to do a refurbish on my spare valve block with new black nitrile o-rings. Bench tested each valve with 6 bar feed, and no leaks. I even check each valve with the solenoid off so I could see the valves. One small bubble around the valve stem seal, but another o-ring fixed that. Put the refurbished block in the car, but still dropping at the back overnight.

Re-checked the air-bag seals, and they look good with no bubbles. The bags were brand new about 3 years ago, and still look in good condition.

Do you know the rear pipes over axle have integrity?

Can you pop the bags out? One of mine had a slow leak where the top cap had shifted enough to leak. Couldn't see it on the car.

Too hot today to get under the car, but yes I can take the air-bags out next week. (Good idea)

Ordered a couple of schrader valves with 6mm fittings today, so I can see if it stays up overnight. This should at least isolate the problem to bags & pipes, or the valve block.

pwood999 said:

Too hot today to get under the car, but yes I can take the air-bags out next week. (Good idea)

Ordered a couple of schrader valves with 6mm fittings today, so I can see if it stays up overnight. This should at least isolate the problem to bags & pipes, or the valve block.

Click to expand...

It is a bit warm to day i got in mine to move it gees it was warm and the back was to the sun good job as only had shorts on the leather was a tad warm,
no way i would be working on a motor.

Could you disconnect the rear bags then plumb a gauge on to the air feeds?
Tell if it’s bags losing pressure or somewhere further forward

Update. Last night I disconnected the two rear airlines from valve block and fitted schrader valves. Inflated both rears to 60PSI and left the car overnight. Unfortunately I didn't measure before & after, but the rears clearly have stayed up (within an inch) overnight.

Now I'm wondering if there's a leak within the valve block I haven't found, or perhaps it's where the airlines enter the block ? The airlines do have some marks from years within the collets, but I could not detect any leaks around them with soapy water.

pwood999 said:

Update. Last night I disconnected the two rear airlines from valve block and fitted schrader valves. Inflated both rears to 60PSI and left the car overnight. Unfortunately I didn't measure before & after, but the rears clearly have stayed up (within an inch) overnight.

Now I'm wondering if there's a leak within the valve block I haven't found, or perhaps it's where the airlines enter the block ? The airlines do have some marks from years within the collets, but I could not detect any leaks around them with soapy water.

Click to expand...

Storage side or where the rubber bits on the solenoids are seated?

pwood999 said:

Update. Last night I disconnected the two rear airlines from valve block and fitted schrader valves. Inflated both rears to 60PSI and left the car overnight. Unfortunately I didn't measure before & after, but the rears clearly have stayed up (within an inch) overnight.

Now I'm wondering if there's a leak within the valve block I haven't found, or perhaps it's where the airlines enter the block ? The airlines do have some marks from years within the collets, but I could not detect any leaks around them with soapy water.

Click to expand...

If they dropped an inch that is not good. Mine doesn't drop that much in a week with everything connected.

Datatek said:

If they dropped an inch that is not good. Mine doesn't drop that much in a week with everything connected.

Click to expand...

Didn't actually measure it Keith, but it hasn't settled any further since Weds evening.

Took the valve block out again today to do bench tests. Used garage compressor to simulate the air tank, and then connected a short airline & gauge to each outlet in turn. Activated Inlet & Corner valve to pressurise that outlet, and left it static for 20mins (see Pic-1). No pressure change at all, so repeated for each corner. For good measure I also removed the solenoids and sprayed soapy water on each valve top (again) while each valve was under pressure. All corner valves seem good so far.

Then connected pressure gauge to Tank feed port, and pressurised via the pump input (activating diaphragm as required). See Pic-2. NRV seems to be holding pressure ok. Next job will be to check tank airline when it's all reconnected.

Also cleaned up the airline ends in the car. They do look a bit worn, but they sealed ok to the Schrader valves over the last few days.

Put the car at extended height & switched of at 13:30 today. Measured top of each wheel arch from floor as a reference.
5.5 hours later the car has changed heights a bit (self-levelling still disabled).

• Front Left minus 5.5"
• Front Right minus 2.25"
• Rear Left minus 1.5"
• Rear Right plus 1.5"

So now it's dropping at the front !! My guess is the 5.5" FL is part of the reason for RR to be 1.5" high. Wish I could find the damn leak.

pwood999 said:

Put the car at extended height & switched of at 13:30 today. Measured top of each wheel arch from floor as a reference.
5.5 hours later the car has changed heights a bit (self-levelling still disabled).

• Front Left minus 5.5"
• Front Right minus 2.25"
• Rear Left minus 1.5"
• Rear Right plus 1.5"

So now it's dropping at the front !! My guess is the 5.5" FL is part of the reason for RR to be 1.5" high. Wish I could find the damn leak.

Click to expand...

Now that's weird. Would that not require at least 2 solenoids to be leaking? Is that with the delay relay in? Thinking spurious signals from driver pack. Blown capacitor in there?

Delay relay is installed but I have separate ignition switched relay that removes power from ECU & delay relay when car is off. I.e EAS completely disabled when parked.

pwood999 said:

Put the car at extended height & switched of at 13:30 today. Measured top of each wheel arch from floor as a reference.
5.5 hours later the car has changed heights a bit (self-levelling still disabled).

• Front Left minus 5.5"
• Front Right minus 2.25"
• Rear Left minus 1.5"
• Rear Right plus 1.5"

So now it's dropping at the front !! My guess is the 5.5" FL is part of the reason for RR to be 1.5" high. Wish I could find the damn leak.

Click to expand...

The plus1.5 may well be due to weight transfer as the front left dropped a lot.

Thought about this all a bit more overnight. Given that on the bench each corner valve didn't even drop 1 psi over 20-30 mins, I think the main suspect is now where the airlines enter the valve block.

Can't be the air-bag ports because they stayed up when using schrader valves, and I cannot see any leaks on those joints. Need to spray more soap around the airline collets, where I suspect the collet scrape marks on the airline are the source of the leaks ?

So now I'm thinking of two options:

1. Cut back the airlines and then make & join new ends. The downside of this is adding new potential leak points.
2. Replace the airline collets & o-rings with compression fittings like this post on RR.net.

pwood999 said:

Thought about this all a bit more overnight. Given that on the bench each corner valve didn't even drop 1 psi over 20-30 mins, I think the main suspect is now where the airlines enter the valve block.

Can't be the air-bag ports because they stayed up when using schrader valves, and I cannot see any leaks on those joints. Need to spray more soap around the airline collets, where I suspect the collet scrape marks on the airline are the source of the leaks ?

So now I'm thinking of two options:

1. Cut back the airlines and then make & join new ends. The downside of this is adding new potential leak points.
2. Replace the airline collets & o-rings with compression fittings like this post on RR.net.

Click to expand...

Take care cutting back the air lines, there is a raised collar to aid insertion, cut back more than a few mm and the collar will stop the pipe going into the second O ring.
No way I would fit compression fittings to worn pipe, the collet and and O rings work perfectly well, better to replace the airlines which is not difficult.

I was thinking about running replacement airlines to each corner but not sure about getting tidy right-angle bends at the valve block ? Don't want kinks in the bends.

Maybe I should do a loose test feed from valve block to all corners & see if it stays level, before doing the fiddly install along the chassis rails ?

pwood999 said:

I was thinking about running replacement airlines to each corner but not sure about getting tidy right-angle bends at the valve block ? Don't want kinks in the bends.

Maybe I should do a loose test feed from valve block to all corners & see if it stays level, before doing the fiddly install along the chassis rails ?

Click to expand...

A loose fit is a good idea for testing.
New pipe can be pulled in using the old pipe.
Bends can be made using heat from a hair dryer or heat gun and a former, @tomcatalan showed a simple former made of wood not long ago.

Datatek said:

A loose fit is a good idea for testing.
New pipe can be pulled in using the old pipe.
Bends can be made using heat from a hair dryer or heat gun and a former, @tomcatalan showed a simple former made of wood not long ago.

Click to expand...

This one,and a hair dryer.leave in situ until cool.

Thanks for the picture. Did you have to heat the airline and then push into the former ?