tracking down o2 system leaks

[peevee]

Looks like it is indeed the cable bending a bit at the bottle valve, making it hard to get shut off completely. In another plane I was a partner o  the cable broke, I'll look at that thread to replace the cable with thicker. 

[DonMuncy]

 

1 hour ago, peevee said:

Looks like it is indeed the cable bending a bit at the bottle valve, making it hard to get shut off completely. In another plane I was a partner o  the cable broke, I'll look at that thread to replace the cable with thicker. 

Measure the diameter of the wire. Check with California Push Pull. Inc. You will have to buy one with a knob, and cut off the part you don't need. My hangar elf changed mine several years ago. No problem since.

[peevee]

We adjusted the rigging of the cable to ensure the valve is off, we can't find any leaks so next test is to replace the oring as it's still leaking with the valve fully off. 

Edited January 22, 2017 by peevee

[DonMuncy]

Did you check the valve which is used to fill the tank?

[peevee]

59 minutes ago, DonMuncy said:

Did you check the valve which is used to fill the tank?

Yes, no evidence of leaking. In fact  no evidence of a leak anywhere. 

Edited January 22, 2017 by peevee

[peevee]

On 1/14/2017 at 8:35 PM, kortopates said:

 

This repair station specializes in O2 equipment and is very good. I really doubt that will be your problem, but easy enough to tell.

 

This is the little o-ring on the high pressure connection to the regulator - its a MS28775-006. This should be replaced every time the bottle is R&R'd and therefore shouldn't leak unless it was damaged on the install and thus leaking from the start.  

 

oops- I see the repair station didn't get included above as intended - this is it:

http://www.c-l-aero.com/

 

Any idea how I know if the oring is compatible with oxygen? 

[Yooper Rocketman]

1 hour ago, peevee said:

We adjusted the rigging of the cable to ensure the valve is off, we can't find any leaks so next test is to replace the oring as it's still leaking with the valve fully off. 

Peevee,

Are you sure you don't have a line running to your gauge that shows tank pressure even with the valve closed?  I thought we found a leak in my line to the gauge that leaked even when the tank valve was shut off.  I could be wrong?

Tom

[peevee]

2 minutes ago, Yooper Rocketman said:

Peevee,

Are you sure you don't have a line running to your gauge that shows tank pressure even with the valve closed?  I thought we found a leak in my line to the gauge that leaked even when the tank valve was shut off.  I could be wrong?

Tom

Yes, the gauge line tees off before the shutoff valve kind of where the fill line tees in. 

Since the tank was recently tested I think a bad or damaged oring is a plausible place to look, and it's cheap. 

If it's the line to the gauge we have problems. 

[DonMuncy]

44 minutes ago, peevee said:

Yes, no evidence of leaking. In fact  no evidence of a leak anywhere. 

Must be magic then   Actually must be in the regulator. That's about the only thing it would be really hard to completely cover in suds.

[peevee]

10 hours ago, DonMuncy said:

Must be magic then   Actually must be in the regulator. That's about the only thing it would be really hard to completely cover in suds.

well, I didn't pull the side panel and check there at the gauge yet. I want to replace the cable so I'll check when I take the interior panel off to do that. For 20 cents I'll swap that oring too. I'll find it... eventually..

Edited January 22, 2017 by peevee

[kortopates]

18 hours ago, peevee said:

Any idea how I know if the oring is compatible with oxygen? 

No need for concern - Its the part no. called out in the Mooney K IPC which you should of course verify. Installing anything else is technically an alteration. 

Edited January 22, 2017 by kortopates

[kortopates]

18 hours ago, peevee said:

Yes, no evidence of leaking. In fact  no evidence of a leak anywhere. 

So it holds pressure over a couple days?

No point in trying to fix something that's not broke.

[kortopates]

20 hours ago, peevee said:

We adjusted the rigging of the cable to ensure the valve is off, we can't find any leaks so next test is to replace the oring as it's still leaking with the valve fully off. 

These are entirely different unrelated circuits. The regulator feeds the low pressure supply line to cockpit ports and would constitute a low pressure leak. The 0-ring is on the high pressure side that feeds the bottle. 

[peevee]

52 minutes ago, kortopates said:

These are entirely different unrelated circuits. The regulator feeds the low pressure supply line to cockpit ports and would constitute a low pressure leak. The 0-ring is on the high pressure side that feeds the bottle. 

I understand that- that's the point.

That high pressure line is before the shut off valve, so it's a potential leak with the valve off. For $.25 I'll change that oring before sending the valve out for repair.

[peevee]

1 hour ago, kortopates said:

So it holds pressure over a couple days?

No point in trying to fix something that's not broke.

What? No it doesn't hold pressure. Leak detection fluid failed to detect the source of the leak.

Edited January 22, 2017 by peevee

[kortopates]

There the low pressure line isn't getting O2 with the regulator off it shouldn't be the regulator leaking but a high pressure leak.

If the o-ring is leaking it'll blow bubbles.

You could disconnect the high pressure line to the tank for a couple days, replace the o-ring, and then reconnect the high pressure line. If you did not loose any air over the time period it was disconnected, you'll then know its a high pressure leak. (there is a needle valve in the inlet to the regulator that will hold the air in the bottle with the line disconnected).

[peevee]

30 minutes ago, kortopates said:

There the low pressure line isn't getting O2 with the regulator off it shouldn't be the regulator leaking but a high pressure leak.

If the o-ring is leaking it'll blow bubbles.

You could disconnect the high pressure line to the tank for a couple days, replace the o-ring, and then reconnect the high pressure line. If you did not loose any air over the time period it was disconnected, you'll then know its a high pressure leak. (there is a needle valve in the inlet to the regulator that will hold the air in the bottle with the line disconnected).

I'm talking about the high pressure supply line o-ring. I specifically said "high pressure line"? Are we talking about the same thing?

The tank was pressure tested in September, so that was disconnected.

Edited January 22, 2017 by peevee

[kortopates]

10 minutes ago, peevee said:

I'm talking about the high pressure supply line o-ring. I specifically said "high pressure line"? Are we talking about the same thing?

I believe we are talking about the same thing - after all there is only one o-ring in the system. Disconnecting that line will de-pressurize the high pressure line and if the needle valve in the regulator holds pressure as it should you should be able to let it sit and see if you stop loosing pressure. There is no where else left to leak IF the regulator is shut off and not leaking (except at the bottle neck which you have presumably already checked). If leaking stops while disconnected, and you have truly eliminated leaks in the back, then that points to a leak in the cabin. I never used this trick, but then I have never had a leak in the cabin area either, but would want to try to isolate it if possible before pulling side upholstery off next to check there.  

 

Edited January 22, 2017 by kortopates

[carusoam]

Oops, I Misfired a post... 

-a-

Edited January 22, 2017 by carusoam

[peevee]

22 minutes ago, kortopates said:

I believe we are talking about the same thing - after all there is only one o-ring in the system. Disconnecting that line will de-pressurize the high pressure line and if the needle valve in the regulator holds pressure as it should you should be able to let it sit and see if you stop loosing pressure. There is no where else left to leak IF the regulator is shut off and not leaking (except at the bottle neck which you have presumably already checked). If leaking stops while disconnected, and you have truly eliminated leaks in the back, then that points to a leak in the cabin. I never used this trick, but then I have never had a leak in the cabin area either, but would want to try to isolate it if possible before pulling side upholstery off next to check there.  

 

we're missing the glass on our o2 gauge anyway, so if I can find a NOS gauge I'll just buy it and replace it when I replace the cable. I guess while I'm there I can replace the line too but I doubt it's the issue.

Edited January 22, 2017 by peevee

[peevee]

to close it up, we found the leak.

it wasn't the oring leaking, but it was the same line, the one that goes from the bottle to a tee fitting and then one leg goes to the fill port and another to the gauge. Somehow that compression fitting didn't get tight enough.

 

We had the oring replaced anyway, it hadn't been in years and was very stiff.

 

Hopefully that'll resolve our issue. We also had a new old stock gauge installed, ours was missing the "glass"

Edited January 30, 2017 by peevee

[peevee]

On 1/16/2017 at 7:45 PM, DonMuncy said:

 

Measure the diameter of the wire. Check with California Push Pull. Inc. You will have to buy one with a knob, and cut off the part you don't need. My hangar elf changed mine several years ago. No problem since.

an easier solution was to find .063 wire at mcmaster carr and feed new wire through from the front. easy peasy. Cost $5 plus shipping and labor.

[DonMuncy]

Just now, peevee said:

an easier solution was to find .063 wire at mcmaster carr and feed new wire through from the front. easy peasy. Cost $5 plus shipping and labor.

I didn't know the larger wire would comfortably go through the outer housing. You have helped a lot of people.

What size was the original?

[peevee]

23 minutes ago, DonMuncy said:

I didn't know the larger wire would comfortably go through the outer housing. You have helped a lot of people.

What size was the original?

in the vicinity of .055

I purchased both in case the heavier wouldn't go but it did, and is less likely to bend. It moves like butter now. I expected to fight it going in but it was no issue at all, just slid through. I had wire lube but didn't need it.

link to the parts list: https://www.mcmaster.com/#catalog/122/3820/=15i9puw

 

part link: https://www.mcmaster.com/#9495K93

 

the part cost is less than shipping, buy both in case .063 doesn't fit. As I said you couldn't tell it wasn't the standard size on ours.

 

Edited January 30, 2017 by peevee

[thinwing]

On 1/22/2017 at 4:42 AM, peevee said:

well, I didn't pull the side panel and check there at the gauge yet. I want to replace the cable so I'll check when I take the interior panel off to do that. For 20 cents I'll swap that oring too. I'll find it... eventually..

Well if you do that is time to lube cable