Message-ID: <002d01bfb181$c2811440$5eb30218@CLNVL1.CT.HOME.COM>
Reply-To: "Neal Garvin" <ngarvin@home.com>
From: "Neal Garvin" <ngarvin@home.com>
To: "Lancair List" <Lancair.List@Olsusa.Com>
Subject: Hydraulic fittings
Date: Fri, 28 Apr 2000 22:22:26 -0400
Mime-Version: 1.0

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I originally used a Loctite hydraulic thread sealant for NPT fittings.
Every one of them leaked!  It was one of the most frustrating experiences of
the entire project.  After searching out the best, hi-tech thread sealer I
thought it would be idiot proof - NOT.

I ended up redoing every NPT threaded fitting with teflon tape - carefully -
keeping it off the first 1-2 threads. I found the fittings easily screwed in
at least two to three full turns further with the teflon tape (which
required me to make a couple longer aluminum lines). I was really amazed how
much easier they went in. The hi-tech loctite stuff must have had poor
lubricating qualities/very high friction that caused me to stop tightening
the fittings well before the mating threads were sealed.

I concluded that the teflon, being a superior lubricant allowed the fittings
to turn in further with much less friction yeilding a tighter leakproof fit
of the mating threads - mechanically sealing off the spiral leak path as
opposed to relying on a sealer compound to do most of the work.

I know they say not to use teflon tape on hydraulic fittings, because small
chards can get in the system causing shuttle valves etc to not seal
completely. But I'd use teflon tape again. Be sure to keep it off the first
two threads and you should be able to turn the fittings in until snug (or up
to the specified torque) then turn additional to the required clocking
position.

You could try Teflon Paste type thread sealer. Keep it off the lead
threads - it will ooze out the front threads and into the system when the
fitting is snugged up. Teflon paste has a high content of abrasive filler
that can cause problems if enough gets into the system.

Experiment with a couple fittings and different thread sealers and use the
one that allows the fittings to thread deeper with minimal friction drag. Be
sure not to over torque or you may crack the body of the female fitting or
component.


>>>Can anyone tell me how to stop a screw-in hydraulic fitting in the right
>>>place, and still make it seal??

>>>I don't think you are supposed to use a teflon type tape.


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