-AN fittings size for trans coolers

[makoshark]

Anyone here familiar with -an fittings. I'm sure they are. Please chime in. On my B&M trans cooler, I can only engage 3 threads of the 1/2" NPT to -6an fitting. That is only hand tight. Will they tighten up more with a wrench and not damage anything? Also, the trans cooler on the radiator is only allowing me to engage 1 thread of the 1/4" to -6an fitting, again only by hand. Will it too tighten up more with a wrench? Or do I need to go to a different size fittings for the trans coolers? The B&M cooler is too large, though, for a 3/8 NPT fitting. Already tried. I don't have an 1/8" npt fitting here to check the cooler on the radiator.

Also, I can't remember, which line on the steering box is the pressure line and the return line? The one closest to the firewall or furthest from it?

[GregWeld]

Originally Posted by makoshark

Anyone here familiar with -an fittings. I'm sure they are. Please chime in. On my B&M trans cooler, I can only engage 3 threads of the 1/2" NPT to -6an fitting. That is only hand tight. Will they tighten up more with a wrench and not damage anything? Also, the trans cooler on the radiator is only allowing me to engage 1 thread of the 1/4" to -6an fitting, again only by hand. Will it too tighten up more with a wrench? Or do I need to go to a different size fittings for the trans coolers? The B&M cooler is too large, though, for a 3/8 NPT fitting. Already tried. I don't have an 1/8" npt fitting here to check the cooler on the radiator.

Also, I can't remember, which line on the steering box is the pressure line and the return line? The one closest to the firewall or furthest from it?

A couple things come to mind -- #1 never try to put two fittings together without some kind of teflon sealant. I prefer the "liquid" paste over the tape...

These fittings will GALL and you might put them together - but coming apart you'll strip out every thread and the part will be unusable.

If you can only engage one thread -- you have a thread mis-match there somewhere...

PIPE THREAD DIAMETER = measure the diameter -- and DEDUCT 1/4" -- so a 1/2 Pipe will measure 3/4" -- minus the 1/4 brings you to "1/2 pipe"...

If the diameter is 3/8" -- then the size is called 1/8 and so on.

The threads in the radiator might be for a double flare fitting... so look inside the "hole" and see if there is just a hole -- or is there a "mound" for a flare fitting to seat against... if so - that's a whole different thread pitch etc.

[makoshark]

Right now I'm just doing mock up. Nothing is tight. Everything has only been screwed on by hand. I do not want any liquids around anything at this moment. Once I start buttoning everything up for final fitment, then I'll do as recommended. Thanks.

I thought about the fitting at the radiator being a different thread pitch. So, if it is, would I need an inverted flare fitting there? As for the fitting on the B&M cooler, I'm still left wondering why only three threads will engage.

[makoshark]

Just checked the fitting on the radiator. There is a mound inside the hole, so it is a flare fitting. Thanks for pointing that out to me

[Rod P]

NPT is National Pipe Thread

Its cut with a taper, that way it pressure fits the connection. 3 threads is about normal it will go in more with a thread sealer paste (don't use Teflon tape please) there is no real lubricating property in tapes

on the 1/4 one it sounds like there are 2 different thread pitches, don't force it, make sure its a 1/4-20 or a AN, a flair or even metric

[makoshark]

the 1/4" fitting I have is a 1/4" NPT to -6an fitting. Only one thread will start, so I have not tried to force it. I know this fitting does not fit the trans mount cooler. The question is, what freaking fitting fits it? I am digging through the mail-order places and not finding anything. What is everyone using there?

[GregWeld]

No "right answer" to that -- because it depends...

Depends on what your female is.... and nobody can see that from your pictures - and even then we'd be guessing. If you have a inverted flare then it's going to take an inverted flare fitting -- not a NPT fitting.

Most likely your radiator trans cooler takes a 5/16" HARD LINE... with a 45* double inverted flare... so if you're going to try to convert that to a -6 AN - you're going to have to figure out what it SHOULD take and then try to find a conversion fitting.

[Vegas69]

Are you sure the cooler isn't AN threads? They are different than NPT.

[GregWeld]

Best thing to do is figure out who made your parts -- and ask THEM --- otherwise it's just wild guessing....

You'll find plumbing very frustrating until you figure out what all these different fittings look like === hot rod parts can be ordered with many different "custom" thread types and sizes... one guy might need his cooler with "O" ring fittings another guy might want NPT to use a barbed hose... that's why nobody can just tell you "IT'S THIS".

[GregWeld]

These guys might be your best new friends.....



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