Sealing a NPT fitting
#11
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Re: Sealing a NPT fitting
I would believe that the thread looks as though it is a NPT but it more than likely is SAE straight thread with an o-ring. Both NPT and SAE can have the same threads per inch except one is tapered and one is straight. If it is a straight thread, tapping it out requires a special tap.
Keep in mind they can both look VERY much alike but are very different. It would only make sense to have a high pressure o-ring type of fitting in this installation. Latham and MM both use straight threads not NPT
Hope this helps
Keep in mind they can both look VERY much alike but are very different. It would only make sense to have a high pressure o-ring type of fitting in this installation. Latham and MM both use straight threads not NPT
Hope this helps
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47 Lightning SE
47 Lightning SE
#12
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Re: Sealing a NPT fitting
Originally Posted by Bad Girl
I would believe that the thread looks as though it is a NPT but it more than likely is SAE straight thread with an o-ring. Both NPT and SAE can have the same threads per inch except one is tapered and one is straight. If it is a straight thread, tapping it out requires a special tap.
Keep in mind they can both look VERY much alike but are very different. It would only make sense to have a high pressure o-ring type of fitting in this installation. Latham and MM both use straight threads not NPT
Hope this helps
Keep in mind they can both look VERY much alike but are very different. It would only make sense to have a high pressure o-ring type of fitting in this installation. Latham and MM both use straight threads not NPT
Hope this helps
Steering operates on a much higher pressure than engine oil. The hose and fittings are 3,000 psi rated.
#13
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Re: Sealing a NPT fitting
The fitting I am talking about is IMCO part # FA-14, and the filter is part # HO-18. The catalog describes the fitting as "1/2" M.P. to Metric O-Ring (Brazil) adapter" The leak is where the fitting screws into the filter. The filter says "1/2" F.M.P.T. 1500 PSI max pressure". That makes me wonder? 1500 PSI Max? I assume IMCO knows what they are doing.
Thanks for the replies, I'll let you know how it goes.
Thanks for the replies, I'll let you know how it goes.
#14
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Re: Sealing a NPT fitting
The steering probably doesn't operate at a pressure much over 200PSI when in static, but it may go as high as 1,000PSI under load- probably a bit over that under extreme conditions. I'd imagine they are using an off-the-shelf filter mount- something similar to a remote engine oil filter mount. A suggestion would be to convert this to a commercial-duty hydraulic system filter. You can get them at any Aeroquip distributor, Grainger or McMaster-Carr. The outlets on the filter adapter would then be o-ring fittings. You could then buy filters locally.
#15
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Re: Sealing a NPT fitting
I had the same problem with my IMCO steering a few years back and used Gasoila to seal the threads.
Here's a link.
http://www.gsasupplyco.com/gasharvartyp.html
Here's a link.
http://www.gsasupplyco.com/gasharvartyp.html
#16
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Re: Sealing a NPT fitting
I removed the fitting, cleaned the threads, used teflon tape, re-assembled. I ran for about 1.5 hrs. today and no leaks.
Hopefully this is the end of the story.
Dave M.
Hopefully this is the end of the story.
Dave M.
Last edited by Dave M; 03-22-2005 at 07:14 PM.