torque for mixed steel/alum fittings

[prkaye]

The chart in the std a/c handbook has different values of torque for aluminum alloy tubing, bolt, fitting or nut as it does for steel tubing, bolt, fitting or nut. What if you are putting one against the other, like a steel nut on an aluminum fitting? I'm assuming one should use the lower value (the aluminum value)?

[DanH]

To which chart do you refer?

[prkaye]

Originally Posted by DanH

To which chart do you refer?

I'm away for the week and don't have the handbook with me... but I think it's in the section of the book on AN fittings. I'll look up the page number when I get home next week.

But regarding my question, is my supposition correct?

[DanH]

I was trying to figure out what you were bolting together. The section on AN fittings, eh? I assume you're talking about a steel AN818 nut on an aluminum flare fitting. If so, yes, use the torque value for aluminum.

[prkaye]

specifically the question has come up because I want to use a steel AN "T" fitting in the brake fluid reservoir. This is a pipe thread joint (so I don't think those same torque values apply), but the other two sides of the "T" will connect to the aluminum AN fittings on my fuel and brake lines.
Which leads me to another question - the fittings on the Bonaco braided stainless steel brake lines, am i correct in assuming these are aluminum? They're not blue, so maybe they are steel as well... of course if they are steel then I still have the mixed alum-steel joints where they connect to the AN fittings that go into the master cylinders.