1. Has anybody else seen this in their axles during tire swaps etc.? I've had axle sliders on for the last ~4,500 miles if that's pertinent at all. Only present in the rear axle.
An update. DO NOT use Apple Cider Vinegar on your axles to remove this material. The vinegar will react and darken the finish (pulls carbon out of the aluminum?). I let it soak for ~1 hour and came back to a rather dark finish surface. I would have taken pictures, but I wanted to address the issue as quickly as possible. Luckily I had some Meguiar's Mag & Aluminum polish, so I used that and some steel wool to polish the exterior back up. This worked, but the inner surface, while clear of the white powder is now a dark rust color (don't think it's actual rust).
I had some CLR handy so I picked the bottle up to put it to use as suggested, but upon reading the label I decided against it. The label on standard CLR says explicitly not to use it on aluminum. However, they make a product called Metal Clear that I may go hunting for tomorrow. http://www.jelmar.com/CLRMetal.htm
Other options of varying degrees of undetermined inadvisability: Mineral Spirits Muriatic Acid
Kenm123t, stick to the politics verses giving advice on cleaning. Phosphoric Acid is also used as a cleaner. What is in coke is a lower amount, but it will clean stuff.
Phosphoric acid may be used to remove rust by direct application to rusted iron, steel tools, or other surfaces. The phosphoric acid changes the reddish-brown iron(III) oxide, Fe2O3 (rust) to ferric phosphate, FePO4. An empirical formula for this reaction is:
2 H3PO4 + Fe2O3 → 2 FePO4 + 3 H2O
Liquid phosphoric acid may be used for dipping, but phosphoric acid for rust removal is more often formulated as a gel. As a thick gel, it may be applied to sloping, vertical, or even overhead surfaces. Different phosphoric acid gel formulations are sold as "rust removers" or "rust killers". Multiple applications of phosphoric acid may be required to remove all rust. Rust may also be removed via phosphate conversion coating. This process can leave a black phosphate coating that provides moderate corrosion resistance (such protection is also provided by the superficially similar Parkerizing and blued electrochemical conversion coating processes).
that krud was all over my axle, I assumed it to be dried up lithium grease. On my last tire change it made getting my axle out a bear. I had a 3/8 extension in the center and banged it off with a hammer. kind of effed up the extension. I sanded it off and gave the axle a liberal coat of anti-seize.
I considered using Coke, but doing further "research" on Youtube revealed it to be less effective than vinegar.
I went to Home Depot trying to locate an aluminum specific cleaner such as the CLR Metal Clear, but they did not have any. The staff was unaware of any product they carried that was safe for aluminum, and many of their suggestions specifically precluded use on aluminum on their labels. I will have to go back and look for the Phosphoric Acid cleaner if WD-40 doesn't cut the mustard.
All this search for an aluminum safe cleaner/oxidation remover was apparently in vain however. I just tested the axle, and it is definitely magnetic. On the other hand it definitely showed signs of carbon reaction with the vinegar. Possibly a steel aluminum alloy?
Application of copious amounts of anti-seize duly noted.
Wire wheel, wire brush, coat with anti seize in the threads and WD40 (Water Displacer, 40th recipe) on the rest, install without sliders. They're what's trapping the moisture in the axle to begin with...
I think I'll be willing to remove the sliders and inspect/clean on a regular basis as opposed to doing without them. But the numerous admonishments to use anti-seize will definitely be heeded.