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AT Compression Tester O-ring

G

GSITFlyer

I'm New Here
I've got an older ATS compression tester with an 18mm spark plug adapter. The O-ring on the adapter (which seals the adapter into the spark plug hole) has hardened and crumbled into little bits. I'm looking to replace that O-ring - but I am utterly unable to find out what size O-ring is used. The O-ring fits into a groove machined into the base of the adapter.

12-05064.jpg

I contacted Aicraft Tool Supply to ask them, and their response was "it's an 18mm O-ring." Well thanks, but I know that already. What I'm looking for is the ID/OD and/or thickness and material, or better yet - a supplier part number. The ATS rep when pressed replied with "all I can tell you is that it is an 18mm O-ring, and our internal part number is PT1118." It's not available for order from their site. That's again not very helpful.

Anyone have a fresh one that they could measure, or better yet - have you replaced this O-ring, and what did you use?
 
Remove the old O ring and take it and the part to any hardware store. Anyone that works there can find a replacement for you.
No part number needed...... In your application, this is not a critical fit.
 
gasman said:
Remove the old O ring and take it and the part to any hardware store. Anyone that works there can find a replacement for you.
No part number needed...... In your application, this is not a critical fit.
Click to expand...
I would normally do just that - except it crumbled to bits when I removed it!
 
GSITFlyer said:
I would normally do just that - except it crumbled to bits when I removed it!
Click to expand...
That is why I said take the adapter with you.... the O ring presses against a flat surface when installed in the head....
ANY O ring that will fit on the adapter will work just fine. Remember, this goes in hand tight.
 
As gasman said, not a critical fit. Any o ring with approximately 3/4" id will work. Hand tighten, you will hear it leak if not tight enough. Thicker o rings are preferred since we just hand tighten.
MS29513-115 will work
 
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