Looking for o-ring part number

Darryl Snover

Darryl Snover

Pre-takeoff checklist
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Continental io-360 on a Cessna 172, has an oil sump drain valve, with markings 71C-3H, S1964-4. There's an o-ring on that seals it, and in my case, the o-ring has seen better days (well, decades...). Does anyone have the part number for the o-ring? My A&P wants the 'correct' part number, and doesn't want to guess which o-ring it is. My google skills are apparently lacking, as I can't find a part number for just the o-ring....
 
Darryl Snover said:
Continental io-360 on a Cessna 172, has an oil sump drain valve, with markings 71C-3H, S1964-4. There's an o-ring on that seals it, and in my case, the o-ring has seen better days (well, decades...). Does anyone have the part number for the o-ring? My A&P wants the 'correct' part number, and doesn't want to guess which o-ring it is. My google skills are apparently lacking, as I can't find a part number for just the o-ring....
Click to expand...

Sometimes those sump valves use proprietary o-rings with non-standard dimensions and rubber compounds. If that is the case, might be easier to just get a new valve. They aren't very expensive as airplane parts go.
 
Ed Haywood said:
Sometimes those sump valves use proprietary o-rings with non-standard dimensions and rubber compounds. If that is the case, might be easier to just get a new valve. They aren't very expensive as airplane parts go.
Click to expand...
Aircraft Spruce sells the Saf-Air valves, and they stock the parts for them too.
 
Darryl Snover said:
Continental io-360 on a Cessna 172, has an oil sump drain valve, with markings 71C-3H, S1964-4. There's an o-ring on that seals it, and in my case, the o-ring has seen better days (well, decades...). Does anyone have the part number for the o-ring? My A&P wants the 'correct' part number, and doesn't want to guess which o-ring it is. My google skills are apparently lacking, as I can't find a part number for just the o-ring....
Click to expand...
If it is decades old I would install a new drain valve with fresh o rings if that what they still use to seal it.
 
I've got a P5000 Saf-Air valve on my Lycoming, their website even has a table of the standard o-ring part numbers that fit each valve.

www.saf-air.com

Replacement O-Ring Manufacturer | Saf-Air

Saf-Air is is an aviation supplier for replacement o-rings for both fuel and oil drain valves. Our o-ring chart helps you find the correct size o-ring.
www.saf-air.com
 
Thanks for the answers. I'll see if the owner will go for a new Saf-Air valve. The original is unavailable new, at least at any kind of reasonable price.
 
Darryl Snover said:
as I can't find a part number for just the o-ring....
Click to expand...
I've never seen OEM replacement orings offered for that original quick-drain. However, you can match them but that is not what you want. Regardless, as mentioned, I'd usually recommend installing a valve assy that does offer replacement seals.
 
I know this is an old thread but since I stumbled upon it while looking for a new seal here's what I found/use:

McMaster Car 8297T168

Viton® Fluoroelastomer Rubber

Dash Number 109 Width 3/32 ID 5/16 OD 1/2 Durometer 90A (Hard) Temperature Range -20° to 400° F

$4. for a pack of 10. The one I removed from my 182 shattered when I just touched it with a pick. Most likely a 1978 original.

In the '70s I was a mechanic at a Beech dealer. New planes came with a plug and we installed the quick drains at the first oil change. New seals were in stock too. I was amazed that they were so difficult to find by P/N now but the Viton with the exceptional temperature range is my solution.
 
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