A parts question; A junkyard question Options

[Langing]

Have never done it before, but I plan on visiting local auto junkyards very soon to try to find a steering knuckle to replace the one I have that has bent ears. I'm looking for two things: advice on using auto junkyards from you experts, such as how to know the part was not involved in a collision if it has already been removed (and yeah, I'm a little scared of the dog), and I need to know what vehicles used the same knuckle as my manual 94 Celica ST Coup (1.8L) w/o ABS. I know it's the same for all 94-99 Celicas, but are there any others that used the same part?

The Toyota part number is 43211-29015.

Would very much appreciate getting advice.

TIA

[timdog1720]

Have never done it before, but I plan on visiting local auto junkyards very soon to try to find a steering knuckle to replace the one I have that has bent ears. I'm looking for two things: advice on using auto junkyards from you experts, such as how to know the part was not involved in a collision if it has already been removed (and yeah, I'm a little scared of the dog), and I need to know what vehicles used the same knuckle as my manual 94 Celica ST Coup (1.8L) w/o ABS. I know it's the same for all 94-99 Celicas, but are there any others that used the same part?

The Toyota part number is 43211-29015.

Would very much appreciate getting advice.

TIA

Wouldn't you need extreme heat to bend ductile Iron? do you have pics of the bend?

[Langing]

Have never done it before, but I plan on visiting local auto junkyards very soon to try to find a steering knuckle to replace the one I have that has bent ears. I'm looking for two things: advice on using auto junkyards from you experts, such as how to know the part was not involved in a collision if it has already been removed (and yeah, I'm a little scared of the dog), and I need to know what vehicles used the same knuckle as my manual 94 Celica ST Coup (1.8L) w/o ABS. I know it's the same for all 94-99 Celicas, but are there any others that used the same part?

The Toyota part number is 43211-29015.

Would very much appreciate getting advice.

TIA

Wouldn't you need extreme heat to bend ductile Iron? do you have pics of the bend?

I am almost certain (since I know it has been done before) that if I tried I could use heat (as you are suggesting) to bend the ears back so they align the caliper mounting bracket with the rotor, even though this part is said to be cast iron ('said' by whom I do not know; perhaps I initially made that assumption and it was reinforced?). Another 'it has been said' is that the common wisdom says "Cast Iron Doesn't Bend." But until you made your statement, I had not heard anyone say it was 'ductile.' Actually, I've only heard the opposite, namely that cast iron does not have a "Yield" specification because no materials testing can show at which point of any bend a part made of cast iron might just break, snap.

Your statement lead me to Wikipedia where I did find some interesting and related information:

"Ductile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spherulitic graphite cast iron[1] and SG iron, is a type of cast iron invented in 1943 by Keith Millis.[2] While most varieties of cast iron are brittle, ductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions." and

"Ductile iron is not a single material but is part of a group of materials which can be produced to have a wide range of properties through control of the microstructure. The common defining characteristic of this group of materials is the shape of the graphite. In ductile irons, the graphite is in the form of nodules rather than flakes as it is in grey iron. The sharp shape of the flakes of graphite create stress concentration points within the metal matrix and the rounded shape of the nodules less so, thus inhibiting the creation of cracks and providing the enhanced ductility that gives the alloy its name." and

"In materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized by the material's ability to form a thin sheet by hammering or rolling. Both of these mechanical properties are aspects of plasticity, the extent to which a solid material can be plastically deformed without fracture."

I did not know about ductile cast iron prior to reading your comment! All you have to do now is prove to me that Toyota steering knuckles are made of this type of cast iron and I might switch my conclusions (and since it was invented in 1943, it's possible), however, until I know for certain what metal these knuckles are made of I am compelled to default to my prior personal theories, which include:

Most times a piece of cast iron is bent, it just unbends when the stresses are released. There are many considerations one must deal with when working with cast iron, far more than I first thought, and many of the issues I have tried to discuss on the threads I posted about my current brake rebuilding project. If interested, search for topics started by Langing. There you will find at least six examples from around the net where people reported bent ears on steering knuckles, pretty much debunking the myth that cast iron doesn't bend, unless the Toyota steering knuckle isn't made of cast iron the likes of which most people are familiar, which is precisely what you implied.

However, all that said, being conservative in the positive sense, the uncertainty presented by the facts I have uncovered concerning cast iron lead me to (justifiably) fear using a knuckle that has once been bent, and to believe that for this critical safety part, I need to either get a new one or find an old one which I know has not been subjected to the forces of a collision. Imagine travelling along at 80 mph and having to slam on your breaks, and since the front brakes provide about 2/3rds of the stopping forces, the ears on your right front steering knuckle, which normally support those forces with ease, in this case happen to break along fracture lines produced on the ears back when you bent (with sudden impact) and unbent (using heat) them. The caliper mounting bracket comes loose of course, while the rotor is spinning at the same speed of the tires. What happens next seems to me. . .

There is also among my postings a link to a site where people who are expert metal workers discuss "bending" of cast iron. It's an interesting thread to read. My take away is that whatever crystal-like micro-structure exists inside cast iron is much unlike other metals (namely it is non-ductile), and it can make sudden and unexpected rearrangements when stressed laterally, usually causing it to crack apart like a brick would if laid across two supports lengthwise and forced downward at its mid-point. I think it is probably reasonable to claim that cast iron doesn't like being bent.

And there are other 'sudden rearrangements' of its micro-structure that do let the cast iron bend. For example, there are reports of extremely heavy metal working machines placed on uneven surfaces for a number of years, some of which show signs of minute bending that somehow becomes part of the large cast iron piece such that it does not snap back to square when moved to a level surface.

As to photos of the ears that show the 'bending' I tried several times to capture that in a beautiful pic so I could show it around, but all photos I took required explanation since the bending didn't show up well, probably since I was doing it myself, and it is not all that much of a bend. It is just enough of a bend to cause a brand new rotor to crash with the side of the caliper mounting bracket, but not enough for the older, much thinner old rotor to crash with the mounting bracket, so until I began this project I didn't even know it was bent. It was, let us say, hidden damage from when my wife struck a curb with the right front wheel. If I do get a good photo I will come back and post it here.

Sorry for the long answer cause basically I believe you are correct I just do not know what actual metal is being used in the Toyota knuckles and don't know how to go about finding out.