A couple comments for discussion:
I noticed that the 4/98 Scubapro chart posted by Superstar has 3 o-rings
The last 3 o-rings listed as p/n 363, 323 and 360 are shown under the "SIZE N" column as 5-101, 5-125, & 5-179. Those size designations appear to be Parker Seals designations for nonstandard dimensions for which Parker tooling is available. At least, the first 2 agree with the Parker size chart but the third is off a bit. The SP chart shows the 5-179 (SP p/n 360) as a 6mm by 1mm but the Parker chart shows it as 6.07mm by 1.02mm (A small difference but the only one that is not a precise match.) The SP chart also seems to have switched the p/n on the first 2. The smaller o-ring used to seal balance chambers should be the SP p/n 363 (aka 399 on older schematics) and the other that is used on the D-series poppet is the SP p/n 323. It would not be the first time I have seen errors like this in SP schematics.
First off, the easier one. The SP o-rings, p/n 360, which are shown in a 3/99 D400 schematic as used to seal the D400 replaceable orifice. These o-rings do not show in a 12/97 D400/350/300 schematic so I guess the replaceable orifice came along after that. So, if you are dealing with a D400, you may have to disassemble a bit to determine whether you need those o-rings or not. Those o-rings are not in the current D400 kit but do look like they are in the older (small, hard plastic package) kit. I think this goes along with DAAquamaster's description of a mid-production change in the D400. (Eyeballing those o-rings through the plastic case, they sure don't look to be 1mm either. They look much thicker. So I don't know what is going on here.)
Next, the small balance chamber o-rings, SP p/n 363 (aka 399). They show on the 4/98 chart as being 2.54mm by 0.97mm which is the size of the Parker Seal 5-101. (I remember looking at the Parker chart and thinking that might be a candidate when I was trying to find that o-ring) On another SP document, the kit table p/n 45-078-101, dtd 03/2002) which was packed in service kits a few years ago; the SP o-ring p/n 363 shows as being 2.2mm ID and 1mm wide. I was surprised to see it as being 2.54mm ID and 0.97 in the SP 4/98 chart. )It made me especially worried as I provided the 2.2 x 1 size for the buy that a group of us made. I hope I didn't screw us up.) So I got out my newly acquired el cheapo calipers and samples from old (used, blue) 363/399, new, from Scubapro, 363, and new from our group buy 2.2 x 1 orings. I decided the caliper was just not precise enough to made a reliable measurement trying to detect a 0.3mm difference so I set out to find gap that these o-rings would just slip through. After doing this a couple times, I concluded that the older. blue o-rings are slightly larger than the other two. That is, when I got down to the critical where some when through and some did not, the blue one got stuck every time and the other 2 slipped through. I then repeated this with the 2 new o-rings and did not find any difference. That is, they either both slipped through or both did not. So, I think we are OK with our 2.2 X 1 generics but looking forward to someone confirming this in a regulator.
Finally, if anyone has any help in confirming the actual size of the SP o-ring p/n 360, I'm sure some D400 owners will be grateful.
