[Berchmans]

How tight should the fuel fittings be installed in the fuel valve. When I spin the fittings in finger tight it only takes about an 1/8 of a turn with a wrench to line them up in the orientation shown on the drawings, it does two wrenches to make this adjustment. Is this sufficient or should they be turned another 360 degrees.....in other words how tight is too tight? I don't want to break the fitting off or dork it up...

 

[bruceh]

-04 AN nuts get 100-140 in-lbs.
-06 AN nuts get 150-195 in-lbs.
Alternately you can tighten to a 1/4 turn past hand tight.

I got this information out of an Aeroquip Performance Products catalog.

 

[Berchmans]

Ah yes, I have the same manual but does that apply to the 90 degree fitting itself? If turned until a specific resistance is met than the orientation cannot be controlled.

 

[Mel]

I think Burke is talking about the NPT fittings here, not the "B" nuts. Pipe threads can be turned up to 360? after finger tight to attain proper orientation.

 

[Berchmans]

Thanks Mel...that's what I was looking for...don't want to snap that bugger off in the valve by overcranking on it...but just past finger tight did not seem adequate.....I will be spending the day bending fuel lines...

 

[g zero]

use a pipe tap to cut the threads a little bit to get the proper torque/final clocking of the fitting

 

[Walt]

I might add that pipe fittings need to be tight, I can't tell you how many leaks I've found attributed to loose fittings (most folks are scared to really crank em down). Thats also why I prefer steel fittings as most of these are going into aluminum and the steel prevents galling so less worry when really cranking down on them (plus they are stronger). You can also try working them down a few times (tighten em down hard then remove, relube and reinstall). Also swapping out with a different fitting can sometimes give you just enough extra to line it up.

 

[PCHunt]

Not so sure.....

use a pipe tap to cut the threads a little bit to get the proper torque/final clocking of the fitting

Disagree. I don't think cutting threads on an AN fitting is a good idea. AN threads aren't cut, they are rolled, and have a different profile than cut threads. Cutting will introduce sharp edges, which may not seal correctly.

Try setting and resetting as mentioned by Walt. And don't forget to lube.

OMO.

 

[Berchmans]

Thanks for the suggestions...just at the fit up stage so far so still quite a ways from final installation...I was helping a mechanic work on a AT-6 yesterday and he really had to reef on one of these fittings to stop a brake fluid leak...pretty sure they can take the stain after watching him...suggestions on the type of lube?

 

[mcencula]

Thanks for the suggestions...just at the fit up stage so far so still quite a ways from final installation...I was helping a mechanic work on a AT-6 yesterday and he really had to reef on one of these fittings to stop a brake fluid leak...pretty sure they can take the stain after watching him...suggestions on the type of lube?

Fuellube or Easy Turn Lubricant.