8v_chris said:

I’m sure this has been flogged to death and then some but I didn’t find a response to a similar question online and I’m pretty much just rambling out loud here but hopefully the huge knowledge base here will know. Can a leak on the EAS be detected using a UV type dye similar/the same as used on an AC system to nail down a leak? I’ve had a slow leak on my EAS for a wee while now and it needs addressed so as not to burn out my pump.

The situation - my EAS inflates as normal, works as normal (ignoring a recent pump failure prior to valve block rebuild), goes from empty tank to full tank in about 8-9 minutes or so with the door open etc, and crucially, the air bags do not lose any air at all overnight; no low corners indicating a bad bag and she will sit up nice and high for days on end with no problems. The tank however will have emptied itself to about 20 psi over say two days. This morning it was full at 130 psi and over 4 hours dropped to 90 psi. I’m monitoring this on my inline pressure gauge plumbed in on line 6 between the level block and the tank.

What I’ve tried - I found that about a few weeks ago my diaphragm valve in the valve block was leaking and air was moving back through valve block, through the air dryer and out into the air. This was found by the bubble mixture method. I’ve stripped the block down and did a full rebuild from X8R, using the Vaseline in the right places and it sealed it up nicely. I’ve been round and round the while system with more bubble mixture but haven’t found anything since despite this weep of air showing on my air pressure gauge. I also ran a temporary line between the gauge and the tank thinking maybe there was a leak in the line but it’s just the same. I’ve also capped off the tank from the rest of the system using a black plug just after the valve block and seeing the same effect - air leak leaking, so I don’t think it’s the tank and it’s plumbing, it’s somewhere in the valve block. Should also note that watching the gauge the leak is there whether the engine runs or not.

With no bubbles appearing anywhere I’m at a loss and don’t really want to pull the valve block apart again but not know where is “bad” nor do I want to chop up my EAS adding in manual valves etc. in my mind this opens more problems further down the road. So going back to my original question - in this scenario would UV dye in the EAS work? Thanks!

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Datatek said:

No to UV dye and as far as I'm concerned, it's no to Vaseline. Have you checked the dryer for leaks, they rust like the tank.

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8v_chris said:

Yes, I’ve had the dryer out and apart, replaced all of the o rings and the ballast type stuff in there too. I had the tank out a while ago as it has service rust on it. Took it back to bare metal with a poly carbide disc and coated it with por15. There wasn’t anywhere obvious on it that seemed to be holed or at least corroded enough to have a hole. I’ve also thrown loads of bubble mixture up and around the tank and couldn’t see any bubbles. That aside though, the pressure still drops when the tank was capped off with a blanking push fit plug.

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Datatek said:

Where are you measuring pressure when the tank is capped off and where is the cap.
Have you removed the filter/silencer at the rear of the valve block and checked for leaks there?

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8v_chris said:

I have a T piece I fitted into line 6 just after the pipe for the tank leaves the valve block. One end runs on to the tank as it should the other to my wee gauge.

When capped off, I just pulled the pipe to the tank out and replaced it with a small length of pipe with the cap in it so the pressure reading is being taken from the valve block to the plug. Hopefully I’ve described that properly!

I’ve had the exhaust silencer off but can’t feel anything, it’s also been sprayed with bubble mixture but no bubbles appear.

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Datatek said:

From your description, it doesn't sound as though you are reading tank pressure but pressure remaining in the system so I must be misreading it.

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pwood999 said:

Soapy water is the best leak finder for EAS. Squirt over every joint, and anywhere else you suspect leaks.

I'm also confused about your tank check. With the system off, the tank pressure should be blocked by NRV-1 from the diaphragm valve & dryer. NRV-2 will be open allowing tank pressure to one side of Inlet valve.

Check for pressure at the dryer port with system off. This will always happen if NRV1 is leaking. Alternatively, it requires both Inlet valve and Exhaust valve to be leaking air.

Inlet & Exhaust valves could also be leaking through the bases. Easy to check by taking the solenoids off & squirting soapy water around the bases while solenoids are off.



View attachment 300839

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pwood999 said:

The valve block does not retain much air when off - i.e. just the main gallery as I described above. It could also be the gauge leaking internally - many cheap gauges do leak. (I have several !! )

Go back to basics. Reconnect the tank line normally & pressurise it. Then check all joints for leaks with soapy water.

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Datatek said:

You do realise that the system is expected to lose pressure, RAVE if I remember correctly specifies a drop over night of around 5/10mm as being acceptable.
I have never found the need to use gauges, if the system works, does not drop excessively and the compressor doesn't run too much then all is well.

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8v_chris said:

I’m sure this has been flogged to death and then some but I didn’t find a response to a similar question online and I’m pretty much just rambling out loud here but hopefully the huge knowledge base here will know. Can a leak on the EAS be detected using a UV type dye similar/the same as used on an AC system to nail down a leak? I’ve had a slow leak on my EAS for a wee while now and it needs addressed so as not to burn out my pump.

The situation - my EAS inflates as normal, works as normal (ignoring a recent pump failure prior to valve block rebuild), goes from empty tank to full tank in about 8-9 minutes or so with the door open etc, and crucially, the air bags do not lose any air at all overnight; no low corners indicating a bad bag and she will sit up nice and high for days on end with no problems. The tank however will have emptied itself to about 20 psi over say two days. This morning it was full at 130 psi and over 4 hours dropped to 90 psi. I’m monitoring this on my inline pressure gauge plumbed in on line 6 between the level block and the tank.

What I’ve tried - I found that about a few weeks ago my diaphragm valve in the valve block was leaking and air was moving back through valve block, through the air dryer and out into the air. This was found by the bubble mixture method. I’ve stripped the block down and did a full rebuild from X8R, using the Vaseline in the right places and it sealed it up nicely. I’ve been round and round the while system with more bubble mixture but haven’t found anything since despite this weep of air showing on my air pressure gauge. I also ran a temporary line between the gauge and the tank thinking maybe there was a leak in the line but it’s just the same. I’ve also capped off the tank from the rest of the system using a black plug just after the valve block and seeing the same effect - air leak leaking, so I don’t think it’s the tank and it’s plumbing, it’s somewhere in the valve block. Should also note that watching the gauge the leak is there whether the engine runs or not.

With no bubbles appearing anywhere I’m at a loss and don’t really want to pull the valve block apart again but not know where is “bad” nor do I want to chop up my EAS adding in manual valves etc. in my mind this opens more problems further down the road. So going back to my original question - in this scenario would UV dye in the EAS work? Thanks!

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Grrrrrr said:

My guess would be the cones on the solenoids in the valve block. @kurtjohnson10 might be able to help you find a replacement.

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pwood999 said:

Look at the diagram & understand the air flows. There's two easy ways to check for slow internal valve block leaks.

1) Reconnect everything without the gauge or tee pieces & fill the tank. Put a balloon over the exhaust silencer, and wait a few hours. If the balloon inflates then something in the valve block is leaking. (balloon will burst if you run the car with it there !! )

2) As above reconnect everything & fill the tank. Then connect your gauge to the drier using an 8mm to 6mm adapter. Wait a few hours. If the gauge rises then NRV-1 is probably leaking.

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