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Place a small flat blade screwdriver between the collar and housing and gently twist. The collar should come out real easy, in fact finger nails alone may work, there’s actually a mating metal brass collar in the housing, so you shouldn't damage the plastic.

Yes there’s 2 O-Rings in each port, once the collar is out you should be able to see them. They sit in a recess around 0.37” deep (all 3 ports the same) they sit literally one on top of the other, so no assembly order, once cleaned push in the 1st one until it expands into the recess, the push in the 2nd one on top of the 1st.

The pipes are held in by friction and air pressure, so any grease will cause them to pop-out, leave these dry (as I discovered)

Normally new valves will have no grease inside, however since mine showed signs of wear I though a tiny amount of SG would help, but that is just my opinion.

I did use an ultrasonic cleaning tank, but brushing and cleaning with IPA (isopropyl alcohol) should work fine.

Just measured the O-Ring sizes:-

• the two 8mm ports are 11.3mm OD x 7.16mm ID (0.445” x 0.081”)
• the four 6mm ports are 9mm OD x 5.15mm ID (0.354” x 0.0203”)

These are most likely nitrile rubber and since it is rubber the above sizes are approximate.

Also the brass pressure sensor (27mm A/F nut) has an O-Ring, which is 19.65mm OD x 15mm ID (0.774” x 0.59”) its possible this could also leak (takes some effort to unddo)

If you have the previous AS unit it could prove very handy 👍

 

So after a weekend at this I do have bit of a victory. While I still cannot get the truck to calibrate, I have fixed the leaks at the compressor ports for the lines to the bags.

I think a couple things were going on to cause the leaks.
First, the shop I had do the work didnt use the H2 air ride line kit I bought from Rebuildmastertech. I dont remember what he said exactly was the issue, but something about them wasnt working. What he used for the high pressure bag lines was common 1/4 inch (6.35mm)OD. I see that what I got from RMT as being specifically for the H2 measures 6mm OD. So I dont know... I see both 6mm and 1/4" are mentioned in threads and I dont have the original lines to confirm what was OEM, but the 1/4inch OD lines are notably beefier and fit more snugly in the ports.

Second, the lines are not formed with the OEM bends. They're just flexible, but straight tubes, so they're pulling sideways on the compressor port where they are routed to the bags. This probably results in uneven seal against the two orings.

What I did.... I didnt remove the compressor assembly or the solenoid block. I did all right from the back of the truck with the bumper removed. I followed oceanbrave's instructions to remove the port lock collars and original o-rings. Mine was all clean and no corrosion. It was sourced from a southern 06 donor. I cleaned in the ports with IPA on a Qtip and vacuumed to ensure no debris in the port. I decided to replace the 18 year old orings and unsuccessfully tried 5-9 and 6-10 common sizes from NAPA. Both leaked badly. I then tried 5-10 from ACE Hardware which were hard to get properly seated in the port, but worked.
Against oceanbrave's advice, I did put a thin coating of marine grease on the o-rings to help get them seated and to help lubricate for inserting the hose into the tighter fitting. I used IPA on the lock collar and plastic line to be sure the lock wasnt fouled by the grease.

Thank you oceanbrave and mixman and others who posted their experiences. Gave me confidence to mess with these aging and imcreasing rare components.

Now if I can just get it calibrated and sitting level!

 

Ok I think I have one other theory for you to try.... I had not seen you post in this thread which is specifically for those who swapped out to the newer style dual pump compressor and since you swapped in a compressor shelf from a 2006 that might be the difference. I know for a fact that the AS module has different software on the newer dual pump style than the older single pump style as GM warns not to attempt to update the AS software on an older model that has been updated with the newer style pumps.

I wonder if the calibration is failing because you are selecting a 2003 (or it was automatically selected by the VIN) in the diagnostic tools you are using?

I think it would definitely be worth trying again but manually selecting a 2006 H2 instead (of auto detecting on some tools) and trying it with that selected as the vehicle.... It might not make a difference as that specific bit of the programming might very well be the same between the generations but maybe not.

 

MixManSC amazing take a look at the other thread