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]

For pictorial completeness, and to share more observations, w/o mounting the brake, I have included photos of the right front tire, as mounted, with lug nuts torqued down.

Examined the tire and suspension for any problems I might know how to check for:

1) Rotated the tire by hand in several ways. When spun, using a stethoscope I can hear what sounds like a "little bit of" metal grinding (not loud, but after 300,000 miles one might suspect that the wheel bearing is showing signs of wear; cannot hear this w/o steth). Also w/o steth I can hear a soft 'clicking' sound that correlates with the speed of the tire (to me I would call that CVJ noise). These two noises are so minimal that I find it hard to imagine them indicating severe problems, although I am reporting them to be complete.

2) When rotating slowly back and forth cyclically while pushing with hands on 9 and 3 things seemed smooth; same when pulling.

3) When trying to push/pull with hands at 12 and 6 (twisting about horizontal axis), I could NOT detect any motion.

4) When trying to push/pull with hands at 9 and 3 (twisting about vertical axis), there was some movement and 'clunking' or 'thudding' coming from the area inside of the tie rod end. Didn't seem bad, but I am no expert.

5) When I tried using a pry-bar to lift the tire in an upward direction, looking for a ball joint problem, there was nothing moving.

6) There is only one more thing that I noticed to be (slightly) imperfect. I measured the sway-bar links and determined that they differ slightly in length, causing one side of the sway-bar to be about 2 mm closer to the control arm (? is it). Such a slight difference, right? Not a problem. . . right?

Ok now for the photos of the mounted tire:

From a distance



Fill the frame:



Centered on the hub?



Straight forward:



Backside (look at that ugly scratch caused by the rotor hitting the caliper mounting bracket):



Ok, I'm done. What other photos might provide key information? Those ears on the steering knuckle still "look" bent to me!