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]

MaskedMan, thank you for the information. I scanned 23 pages of ILoveMySilly97's posting, looking for anything like what you mentioned, but got plumb tired out, fell asleep, and then just gave up and sent a PM.

While writing to ILoveMySilly97, I remembered there is something of significance that I had not yet posted about this problem with the right front wheel of my Celica, and would like to bring it to everyone's attention now. I honestly had not remembered this:


This morning I asked my wife if she had ever hit a curb with the right front wheel and she said "Yeah, remember back when the passenger side motor mount broke?"

She was referring to the time, almost two years ago, right after I had the car in the shop to replace its clutch, when the service technician had failed to replace the nuts on the underside (2 down-facing) bolts of the motor mount (they are difficult to reach, should I blame them for being lazy?).

I was not with her when she struck the curb, but evidently the force of the collision caused the single remaining bolt holding the engine in place at the right side to bust, dropping the engine an inch or so, and later that day when I heard a strange noise and checked, I just proceeded to fix the motor mount. To me, all I had remembered of the incident was that the motor mount had failed, the significance of which (to me) caused me to totally give up on paying anyone to do any of my car repairs out of my sight ever again, unless I was forced.

This event from the past may be significant to this problem (really?), so I am now posting it so anyone who reads about my problem might be able to understand my situation properly, with all pertinent facts on the surface.

I am still waiting on the pack of Federal dial indicators, hoping just one of them is smoothly operating so I can get a reliable measure of the run-out. Will report as soon as I have it.