[2006greyGT]

Am I the only one who thinks the rust on the axle housing is unacceptable? It is the only unpainted surface and they are rusty when the are on a brand new car. I am going to paint mine black this spring. Has anyone else done anything about this or am I just getting anal in my old age?

[mustang fanatic]

Naw I agree, It looks pretty shity, But im not undr there enough to do something about it.

[Luis_GT]

Yours didn't came painted completly?

My whole axlehousing is black... same with the whole underside of my car... even the driveshaft is black...

[06RedfireGT]

Mine is rusty as shit.

[08Eleanor]

My BRAND NEW (1 month old) 08 mustang has rust all over the axle. It is truly unacceptable, but sadly, so Ford-like. I think I might get it painted, but for now I just stay away from the underside of my stang.

[Drick]

I agree

[2006greyGT]

your the lucky one Luis. I am going to try this stuff unless anyone has a better idea. It will stop the rust from coming back..Eastwood Co. - Eastwood Rust Encapsulator Black 1 Qt
.... I am going to do this when I install my gears this march.... My Mustang to-do list is starting to get out of hand..lol thanks for the replies

[Luis_GT]

That's the only good thing... my car's been nothing but trouble.

[IronStomach]

The rust on non-moving parts is an engineered cost saver. The rust will form a protective shell on the axle housing, stock mufflers, and other parts and act like protective paint and actually strengthen the surface. Some large buildings around here were built in the same manner. It just, er, won't look nearly as decent. Unless one likes the color of rust, but that's probably indecent.

[2006greyGT]

so your saying it is structural rust... haven't heard of that...I don't think painting it will weaken it

[06VistaGT]

Painting won't hurt a thing. I'm thinking about doing the same thing. Let us know how it turns out for you.

[psycho bob]

errrr say again......rust will strengthen metal????? last i heard is that rust will eat metal. look at an old car and the cancer that comes with them quite often

[IronStomach]

Originally Posted by psycho bob errrr say again......rust will strengthen metal????? last i heard is that rust will eat metal. look at an old car and the cancer that comes with them quite often

Ever notice how architectural copper rusts (the green patina) but doesn't rust through?

Depends on if the metal was engineered for the layer of rust. What makes aluminum and titanium rust free? A microscopic and transparent layer of aluminum oxide and titanium oxide that forms immediately on the freshly finished metal and inhibits all future rust growth. These layers of oxides (oxidation is rust) are surface only and prevent penetration from eating into the metal structure. Much like the application of bike tubing made from titanium, the exterior oxidation is similar to shot peening where the surface is pelted by tiny metal balls. This metallurgically changes the outer layer of the surface and further hardens the metal.

The problem with the sheetmetal on the car is I believe a substantially softer and different metallurgical composition of metal. The higher the carbon content of the steel, the softer it is, the easier it is to fabricate and the more readily it rusts. Which is why stainless steel is bad for making swords - it's too hard, too brittle and you can't get as sharp an edge as high carbon steels.

Like I said in my earlier post, there are some big buildings in the area, like the main campus of College of DuPage that was constructed with exterior steel designed to form surface rust.

Still doesn't mean it looks any good though. Just cheap process manufacturing to avoid a layer of paint where it's not necessary.

[SoonerStang]

EfylSetaf,

I hate to disagree with you, but ... wait... no i dont, that who i am!

While some of your points are incredibly valid, the oxidation on the axle housing is not the type for structural stability, it is simply another way for ford to make a CHEAP car. remember that ford made the mustang originally for price and performance. the same is true today, they have to cut costs in many ways. obviously one of those ways in this instance was to let rust form on an iron component. IRON oxide is NEVER a good thing. iron oxide is one of the largest contributors to component failures in the automotive, and aerospace communities. as shown in the picture above, the rust goes completely to the gear housing, the intersection of these two sub assemblies will inevitably break down, and create a failure in one of the two pieces, this is commonly known as stress corrosion cracking, as the axle housings are constantly under a varying state of stress.

on your comment of shot peening. while i agree that it increases the surface strenght of the material, you cannot view that alone, the residual stresses induced by shot peening only penetrate to roughly 5nm thick. because a part, any part must always be in equilbrium, the materail beneath the substrate must then be made weaker. while shot peening is good for some applications, it generally makes the part brittle causing substrate failures.

BUT to the larger question here...

ARE YOU AN ENGINEER? you speak like an engineer.

SPEK!!!

[IronStomach]

Originally Posted by SoonerStang EfylSetaf, I hate to disagree with you, but ... wait... no i dont, that who i am! While some of your points are incredibly valid, the oxidation on the axle housing is not the type for structural stability, it is simply another way for ford to make a CHEAP car. remember that ford made the mustang originally for price and performance. the same is true today, they have to cut costs in many ways. obviously one of those ways in this instance was to let rust form on an iron component. IRON oxide is NEVER a good thing. iron oxide is one of the largest contributors to component failures in the automotive, and aerospace communities. as shown in the picture above, the rust goes completely to the gear housing, the intersection of these two sub assemblies will inevitably break down, and create a failure in one of the two pieces, this is commonly known as stress corrosion cracking, as the axle housings are constantly under a varying state of stress. on your comment of shot peening. while i agree that it increases the surface strenght of the material, you cannot view that alone, the residual stresses induced by shot peening only penetrate to roughly 5nm thick. because a part, any part must always be in equilbrium, the materail beneath the substrate must then be made weaker. while shot peening is good for some applications, it generally makes the part brittle causing substrate failures. BUT to the larger question here... ARE YOU AN ENGINEER? you speak like an engineer. SPEK!!!

Gah, unfortunately no, I (mistakenly) studied economics, I always wished I went mechanical engineering or culinary arts. I take it you're an engineer for reals? I'm a cycling geek and that's where I got the info on shot peening. Independant Fabrications and Chris King had some of their research materials online to showcase their quality (and justify their pricing) and some diehards posted to some (now defunct) bike manufacturer forums on the subject of titanium structural integrity and surface peening.

I bow to those with real knowledge though (makes mine fake knowledge? sigh) and agree Ford wouldn't do something better if they hadn't a way to do it cheaper instead. Guess I had just enough info to be dangerous, huh?

So the question now... will painting or coating the axle & gear housings cure it or is there a suitable, long-term replacement part?

[SoonerStang]

I will tell you what i am going to do,

Same thing that i did on my 1970, I am going to sand the snot out of it, prime it and paint it krylon black. If you sand it to a good surface finish, get some rustoleum primer, and good krylon, and you are good with a rattle can, (which i am not, but my dad has done it for 20 years in the AF) you can get a great finish.

Yes i am an engineer, and working on a masters. yours isnt fake knowledge, you did what everyone does, take someone that should be knowledgeable on the subjects word for it, and used it as fact. most the time thats good, unless its wikipedia. but you have to search for their sources, or their resume, and make your own decision. you were right on quite a few issues.

the long term fix, in short, is sand blast it, and paint it. for those of us without a sand blaster, medium grit sand paper, then water and brillo pad, then rattle can!