Mk5/10 seats

[aquaregia]

Unfortunately, I'm using a different IP gauge to the one I had in the past, so I'm not certain it's not just gauge error. My four regulators (Mk10, Mk5, Mk5, Mk25) are 145, 140, 150, 145 right now. The Mk25 is ~15 dives past service, has a 140->145 in 4 seconds. One Mk5 has a lockup a little under a second, the other Mk5 and the Mk10 are pretty much instant.

I don't remember what controls lockup, but I've got Vance's book here so I guess it's time to reread.

 

[Couv]

Just to re-cap:
(Start with good IP gage as this may really be the problem)
Tear down (leave seat in retainer)
Clean and lube
Break glaze on piston stem
Replace hp o-ring with duro 90
Re-install retainer and seat
Test again. IP still high? Back up and remove shims.
Test again. IP still high? Change hp seat.
Sell MK 25

Edit to answer Q:
Lockup is the condition that exist after the hard and soft seat make contact and creep stops. That’s why a well lubed piston stem, piston head & stem o-rings, and the proper hardness o-ring are important. Anything that slows the piston down will increase creep and IP.

 

[LeadTurn_SD]

Another good thread with great replies from the usual suspects. More tools for my mental "toolbox".

Thanks for starting it aquaregia.

As usual, I have nothing to contribute except a friendly so more folks can read it.

Best wishes.

 

[Zung]

+1 for the IP Gauge: get another one. They are fairly cheap if you don't buy them at a dive shop. Mines are very consistent: left, CL 2.5: $30 @ dive shop, center, CL 1: $2 @ eBay, right, unspecified: $10 @ hardware store.

In addition to Bro couv's good advise: inspect knife edge with a loupe. If you have problem with creep or slow lockup, it's that or the seat.