~!@#$%^&*() acetylene leak

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I have this cool old Victor 200 series set of regulators. Made in San Francisco, glass lenses, everything seems to work. Except when I back the acetylene adjusting screw way out and shut off the cylinder, the high pressure gauge creeps down. They all go down eventually, but this one goes down too fast. I tried using Snoop to do a leak test, but I can't find any bubbles anywhere. I figured to heck with it, I'll swap out the POL fitting. Couldn't get the dang nipple unscrewed from the reg body.Anyone got any ideas? I really don't think the regulator case is cracked. metalmagpie
Reply:If the tank is leaking around the valve stem when it has been shut off (so isn't back seated anymore), that will happen. The bubbles should show there if the rate is fast.Is that a single, or double stage regulator? Since you gave the model number,  OA Doc. can probably give you all the details of how it's built.
Reply:http://www.sealseat.com/prod01.htmDownload the Victor pdf for a view of the internals.I remove nipples by crushing them in a bench vise and twisting the regulator body by hand. I also have an aluminum tube that fits over the part of the cap that holds the adjusting screw (remove the screw) I can use for extra leverage without scratching the regulator more than slightly.
Reply:Use a socket wrench to remove the old inlet nipple. With the adjusting screw out, and the delivery pressure gauge not creeping, the only place the regulator can leak is where the inlet nipple is screwed into the regulator body, where the high pressure gauge screws into the regulator body, the cylinder connection, a crack in the regulator body, the acetylene cylinder valve, or the most likely suspect, a leaking gauge.  A leaking gauge is extremely hard to find with leak detector.OAdoctorwww.regulatortorchrepair.com
Reply:Originally Posted by OAdoctorUse a socket wrench to remove the old inlet nipple. With the adjusting screw out, and the delivery pressure gauge not creeping, the only place the regulator can leak is where the inlet nipple is screwed into the regulator body, where the high pressure gauge screws into the regulator body, the cylinder connection, a crack in the regulator body, the acetylene cylinder valve, or the most likely suspect, a leaking gauge.  A leaking gauge is extremely hard to find with leak detector.
Reply:Originally Posted by Oldiron2I once had some balloons, the inlet section of which would stretch enough to get over a whole gauge. With the inlet taped around the stem (if there's enough room; not always), a leak gradually enlarges the balloon. A plastic bag might work, but would be harder to seal and it doesn't stretch well so would be harder to 'read'.
Reply:Originally Posted by OAdoctorUse a socket wrench to remove the old inlet nipple.
Reply:It may actually be better to get it on less than fully tight, attach it VERY firmly to the tank, and turn the regulator until it is fully tightened (without putting pressure on the gauges, or opening the tank).
Reply:Originally Posted by OAdoctorWhen we are rebuilding a regulator and can not kind a high side leak, we simple replace the HP gauge.  But if you do not have another gauge the balloon or bag is a great idea.
Reply:Originally Posted by metalmagpieI might try a latex glove. This high pressure slow leak is bugging me.metalmagpie
Reply:The nipple on this regulator has no hexes or flats, and may be sealed to the body with litharge.metalmagpie
Reply:Saving removed nipples that were pulled for suspected defect is like saving used toilet paper. I'm sure someone does, but I don't. The thing that matters is not to damage the regulator body. Make sure the replacement nipple had the little sintered metal filter insert to keep nasties out of the regulator.
Reply:Away back in the dark ages of the last century I had two stems crack where the nut bears to tighten the stem into the bottle. I was driving on very rough roads all the time and figured that was the cause. Both cracks occurred within a short time and then I never had it happen again although I continued to drive those same roads with the same regulators for around 10 more years.. I don't remember the regulator number but it was a large single stage Victor with glass guage lens and I purchased it in 1970. It will show as if the stem wasn't well seated in the bottle valve.Your set of regulators could be from this era so it might be something to check. The crack can be difficult to see but you should be able to see bubbles but not for long as it will leak down quickly with the bottle turned off.PS. No one in those days pulled their regulators off their bottles while traveling. Now the state DPS frowns upon the practice.