[HO455]

The spools can be removed by pulling them out but the spring side. I don't have a reason why the O-ring came off. The spools have been lubed with a silicone grease which is very sticky I don't know if that was contributing to the failure or not. I had prelubed the valve set as per the manufacturer's instructions with some air tool lube and it is possible the two different kinds of lube didn't play well together. I have never seen a silicone grease in an air valve so I removed as much of it as I possibly could. (I have rebuilt untold numbers of air control valves in a previous life as a tug boat repairman.). Under careful examination I could see no defect on the problem O-ring, the spool, or in the valve body. I replaced both O-rings on the problem spool. They fit very tight as expected. After lubing I installed the spool . Then I inspected the rest of the spools one by one and lubed them all with Pink Grease from Systems Engineering. It is a special grease developed especially for use in air controls.
Photo 1 shows the spool with the O-rings installed. After the O-rings are in place you have to carefully slide the spring over the O-rings and seat it against the lip on the spool. I initially thought this may have been the cause of the failure, but I didn't find any burrs on the springs and they are barely snug as they pass over the O-rings. The last thing I did was to remove the extra grease on the rollers and reapply it where it seemed to be lacking.
For reassembly I lined the back and center pieces up and put the #11 short bolt in to hold them together. Then in reverse of disassembly I inserted the other ten screws and snugged them down and then in half turn increments I tightened them in a circular pattern until all were "Tee handle tight". Don't use a long Allen wrench or socket to tighten these down as they would strip easily. Use a Tee handle or the turn with the short end of the Allen wrench. I plan on calling Aire Jax this coming week to discuss what I have seen and to thank them for the quick service on the O-ring delivery. If there are any insights I will share them.