Right front steering knuckle caliper mounting bracket tabs bent Options

[Langing]

ADDED NOTE: I am not a trained auto mechanic; I try to DIY whatever I can to keep my 300,000 mile Celica happily running. Thanks to a wise comment below, I now see that making the statement 'my steering knuckle is bent' is oxymoronic on its face. The steering knuckle is made of cast iron and it is well known that cast iron does not bend (though exceptions exist). Cast iron acts more like a brick which cracks when a transverse force is placed between its two ends. Nonetheless, there exists a situation with my right front caliper mounting bracket, in conjunction with the disc, that causes it to seem very much like the mounting tabs on the steering knuckle are bent. I am seeking the true explanation for this (at least apparent) bending of a cast iron part. It would be great if some expert in front suspensions would stop by and explain my observations set out below, and pinpoint my problem. Until then, I dare not change the title of this topic; what cannot be is.

2nd ADDED NOTE: After much on-line research, I have been convinced that bending of the tabs (or ears) on steering knuckles is more common than most people believe, despite the fact that "cast iron doesn't bend." Not sure what that has to say about steering knuckle castings, or what exact metal they are made of, but evidently it does happen. See my posting near the end of this thread.

94 Celica ST Coup 1.8L Manual:

Installed a new rotor (measures 0.986"; manual specifies 0.984" maximum). Rotor run-out minimized; much less than maximum. The caliper mounting bracket bolt tabs/ears on my right front steering knuckle are slightly bent toward the rotor (worst is the lower tab; 3/32 inch; shown in following photo). This causes the caliper mounting bracket to be misaligned so much that it interferes with my new rotor.




It has severely scratched the last ¾ inch of the rotor (to the outer rim), during short test drives (less than 1000 feet). Of course it made a lot of noise, but it was the first time I had ever done a job like this and just wasn't aware of the severity of the problem.



What is the best way to fix this problem?

Should I attempt to bend the steering knuckle tabs? Is the steering knuckle a cast iron part? Should I die grind the proper alignment into the caliper mounting bracket surfaces where they meet the steering knuckle tabs? Should I buy and install a new steering knuckle; they cost around $200 and require a lot of work to install?

This post has been edited by Langing: Jun 1, 2014 - 4:44 PM

[Langing]

ILoveMySilly97 did experience bending of an ear on his steering knuckle. He had taken it to Pep Boys to have them press a wheel bearing, and when it came back he immediately could see that they had bent one ear on it. Took it back to Pep Boys and they used heat to bend it back.

From time to time I run into threads on various websites that talk about bending the ears on steering knuckles, such as this one, where a guy beat on his with a 5 pound sledge:

http://www.thechicagogarage.com/forum/car-...ng-knuckle.html

And this one were the guy did much the same thing, namely, he beat his rotors into the ears trying to remove a rusted on rotor that just would not come off. Ended up cutting the rotors off.

http://www.hyundai-forums.com/180-xd-2001-...g-knuckles.html

And another where the vehicle is a Jeep, the owner knows nothing about DIY or auto mechanics, and people are talking about offset ball joints, C-gussets, and other things I have never heard of:

http://www.jk-forum.com/forums/stock-jk-te...nuckle-90726/#b

And some guys in North Carolina riding FJ Cruisers. Guy was wondering how come the steering knuckle ears got bent do easily, when there are so many more delicate parts to the suspension system. One commentor offered the opinion that the ears of the steering knuckle are the weakest parts of the suspension system:

http://forum.ncfjcruisers.com/t594-possibl...teering-knuckle

And one from ToyotaNation that sounded exactly like my experience, so I PMed the guy to see how he finally resolved his problem:

http://www.toyotanation.com/forum/104-5th-...er-bracket.html


So, I guess the ears on my steering knuckle actually could have been bent, most likely when my wife nudged a curb (she claims it was a soft landing). The only other possibility is that somehow the hub/bearing assembly might have been shifted from their installed position such that the disc spins without run-out, but in a different plane, giving the appearance that the ears on the steering knuckle are bent. It's one or the other, and I think the most likely is a bent ear.

If I get the cast iron ear red hot and bend it a small amount, what am I doing to the cast iron part? Will it form 'fracture' lines inside such that it is just waiting till some unusual force causes it to just break off?

This post has been edited by Langing: Jun 1, 2014 - 12:55 PM