OP
Zung
Contributor
On to the 3rd one, serviced by a LDS in December 2009. The IP settles to 131 PSI; on a purge, it drops to 123, then takes a minute to get back to 131.
I remove the piston, again a composite one; it looks perfect. I brasso it for about 5': the edge and the body, both outside and inside. It doesn't look any different after that, and, after re-assembly, gives the exact same results: steady state IP: 131 PSI, 8 PSI drop on purge, and 1 minute to recover, give or take a PSI or so. Btw, the LDS who serviced this one must have a special deal with Christo or Tribo: he coated everything with it.
Oh well, I guess it's all within specs; it just doesn't look good, and it doesn't make sense to me: out of the 4 MK20's, all of them in the 130 PSI range:
I remove the piston, again a composite one; it looks perfect. I brasso it for about 5': the edge and the body, both outside and inside. It doesn't look any different after that, and, after re-assembly, gives the exact same results: steady state IP: 131 PSI, 8 PSI drop on purge, and 1 minute to recover, give or take a PSI or so. Btw, the LDS who serviced this one must have a special deal with Christo or Tribo: he coated everything with it.
Oh well, I guess it's all within specs; it just doesn't look good, and it doesn't make sense to me: out of the 4 MK20's, all of them in the 130 PSI range:
- #1 has instant recovery, maybe 50 dives since last service by a LDS
- #2 has instant recovery, after I replaced the piston, as described above, just serviced myself
- #3 has 1' recovery, serviced a few months ago by a LDS
- #4 also has about 1' recovery, serviced a year ago by a LDS
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