Question about old SP Max Flo 4500 tank seal.

[Calvin]

I recently picked up an old on-gun max flo 4500 tank regulator for my Pro Carbine setup. I will be putting in a velocity adjustment screw cut to leave the power tube unobstructed and using the reg to adjust velocity.
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I have several other ASA mounted LP Max Flo regs, so I have most of the correct size and hardness of orings already. I just ordered the ones needed for the on/off lever, and the HP piston. My question is in regards to this clearly custom seal between the reg and the tank.

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It is ancient and will need to be replaced. Are these standardized and sourceable? Is there an oring size and type that I can substitute in its place? I will be installing a 60ci Bunker Kings tank on it.

[Reflex0283]

To me that just looks like a standard regulator o-ring that's just been crushed after years of a tank being on there

[Calvin]

So, would an 015-90 Urethane oring work in there?

[Reflex0283]

I really don't know the specifics of the tank-side specs unfortunately, but every regulator I've seen has a round o-ring on that part of the reg so it's definitely not proprietary

[Reflex0283]

For what it's worth, I called my local shop and they said that most regulators use a 113 or 114 there depending on the tank you're putting on, though the resources that other people have posted below are probably more correct for the maxflo reg

[nak81783]

I think it’s a -112 oring.

[Jordan]

According to zdspb.com (and it's not a common size, apparently):

[nak81783]

From theoringstore.com

A 907 has an ID of .530” +/- .007” and cross section of .082”
+/- .003”, resulting in a nominal .694” OD.

A 112 has an ID of .487” +/- .005” and cross section of .103” +/- .003”, resulting in a nominal .693” OD.

Technically, Jordan is correct, and I thought a 900-series is what I bought years ago. However, I’ve never had one go bad, and I couldn’t quickly find a source for the exact size. Captain Oring is where I got the 112 info from; it’s what they put in a Ninja reg rebuild kit.

112 should be at your local hardware store if you want to try that first. My guess is it will work, just stretching more over the threads. Not sure a local hardware store will have a 907.

[Jordan]

That's excellent information to have - I have a couple of bottle MaxFlos that need rebuilding but the oddball bottle seal was stumping me.

[Calvin]

I slapped a 112 on there and I'm sending it.