Rio S2K

Can the S2000's suspension parts like control arms, bushings, etc. bend even slightly or will they break under the slightest of strain due to the fact that the majority of the suspension parts are made from brittle cast iron?

Ludedude

The bushings are made from cast iron?

Yes, suspension pieces can bend.

Rio S2K

I'm sorry, not bushings, my mistake, I meant ball joints. Just so I understand this correctly you're telling me suspension pieces which are made of cast iron can bend (physically deform from their intended original physical dimensions) in that if you were to remove let's say the lower control arm and compare to a brand new control arm you would detect a slight deformation in the cast iron pieces w/o any breakage. I understand that suspension pieces can move if let's say the car gets smacked and the car's alignment settings move because these settings are secured via nut/bolt fasteners which can loose grip if the impact is hard enough. I was under the notion that cast iron suspension parts break under the event that the slightest of strain(stress) greater than its yield strain(stress) are sustained. I could understand if steel suspension parts deformed because steel is a ductile material in that it can deform beyond its yield point or point of permanent deformation and still stay intact as one piece but how can cast iron permanently deform and not break due to its brittle nature?

Ludedude

I'd say it's possible, yes. I'm not a metallurgist, nor do I play one on TV, but I think a lot depends on how/where the stress is applied and how fast the forces build on the part. Also, a great deal depends on the metal used; I'm pretty sure that it's not pure Fe that our suspension bits are made of or they'd rust to pieces in short order.

Bassem

Yes, they can bend. It is usually unlikely because the weld of the bracket that they are bolted to would most probably fail, or the bushing will take the brunt of the energy. But if you do bottom out your suspension repeatedly, and use very high spring rates, such events will create some deflection over time.

I hopped a curb once (with my former Subaru) and the cast iron exhaust header bent pretty good. No-one noticed it and no exhaust hangars, bolts etc, bent or broke off. It was only until I was installing a turbo kit and the darned thing did not fit that I discovered it. Thankfully my buddy offered me the use of his.

Cast iron is quite ductile, unless it is cast poorly with many defects. Carbon steels can be quite a bit more brittle however.

Bassem

Rio S2K

I think you have this last statement in reverse. I now agree with you in that the cast iron suspension components can permanently deform w/o breaking. The reason is what Ludedude said: The casting is not pure Fe but rather it is an alloy (molten-state combined mixture of different metals) which makes the cast suspension pieces not behave completely like a brittle material. The fact of whether it will deform or break is also dependent on many other factors such as load(impact) application in terms of force magnitude/direction and duration while also relying on member thickness at those points of stress.

TriaXenginE

my control arm is bent right now, so yeah, they can bend. suspension parts are meant to break easier so as to prevent frame damage.

syncer55

Yea, the parts can bend. Its better to replace them if you start noticing problems than to try to bend or weld them back.

Joe in STL

I hit a curb and the lower control arm BROKE IN HALF! So they may bend a little, but after a certain point they snap.

Rio S2K

You must have hit that curb pretty damn hard to break it since I got a look at that front lower control arm and it's a pretty thick member.