I've had this problem since I bought my 95. When braking I get a grinding from the front end. I have replaced rotors, calipers, ceramic pads, still getting the same grinding. I do not see on the rotor, wheel or tire any unusual wear that the grinding should cause. I do have a little more wear on the top 3/4" of my rotor face, both left and right, but nothing that could cause the grinding that I am getting. I do not have any movement in the bearing hub when pulling at 6 and 12 o'clock, I do have some movement of the suspension at 3 and 9, fixing to address that with new tie rod ends, ball joints and bushings. Is there a way the caliper can be bottoming out on the top edge of the rotor? Can the bearing be grinding without movement? How about the ABS, is there anything that could cause this, no ABS or ASR lights on. If I really bare down on the brakes it is very noticeable. I have 17" Z06 wheels with Firehawk wide oval P285/40 R17 tires. Is there anything in the suspension that could cause the grinding, ball joints, steering rack? I just had it aligned after going through my rear end with bushings, tie rod ends, u-joints and rear wheel bearings. No problems with the alignment job. I am at a total loss. I purchased a Precision wheel hub, 513085, I know it is not a premium Timken or SKF, but for $68.00 shipped on Amazon, I thought I would give it a try. Should be here in a few days. I don't know what else to do. Someone had suggested it could be the tires, I don't think so, it is a definite grind. Surely I am not the only one to experience this issue, but then that would be my luck. At this point I am open to any suggestions. I'm willing to throw more money at it, just need a direction to throw.

 

Being no one has commented, I'll add some questions.
Are you sure it's the front?
Any chance the pads or caliper is hung up? The wear should be even.
As you have non-standard rims and tires I assume, have you looked at the inside of the rim to see if there's any rub marks on it?
Grinding happen any time you touch the brake pedal or is it hard braking?
Going straight or turning? If hard, is there a chance the front end is dropping enough for the tire to touch the hood?
Have you checked the front spring to insure it's ok and tight?
Is it possible it's the wear indicator on the pads?

I had a caliper bolt work loose on my one truck, ground some for a little while according to the wife then it fell out (when she told me about it). Bunch of sparks when that happened.

 

Definitely the front, no wear on the inside of the rim, I replaced both calipers a month ago, thought that might be the problem.
Grinding is more noticeable below 30 mph, but continuous at slow speeds when braking, and more noticeable when hard braking.
It happens when straight or turning. Not rubbing the hood, and it is not the wear indicator. When I replaced the rotors, calipers, pads and caliper pins, everything looked great. I do have a different wear pattern on the rotors, as I said in my op, the top 3/4" of the rotor show wear different than the rest of the rotor, and this is on both the right and left rotors. Not sure what is going on there, but it is a smoothe wear pattern, just noticeable. I did not suspect the front spring since it happens at slow speed when soft braking as well, the spring really does not come into play.
If the problem is the calipers, hence the different wear pattern, it is a smoothe wear pattern, so why the grind?

 

I would go with the hub. Usually this kind of problem is in the rotating area. Its a good chance it has to do with the abs sensor mechanism.

 

You have me stumped. Only things I can think of is the spring on the top of the brake pads (if yours is like mine) or the hub itself. If it's the hub, then why isn't it grinding when not braking? If the spring, again I would think it would sound off even when not braking?

Very perplexing.

 

I agree, I'm stumped. I will get my new bearing assy in a few days, going to install it and will post the results.

 

Is the wear on the rotors, on both sides of each rotor. Did the old brakes have the same wear pattern?

 

The wear is not on both sides, and I don't recall if the wear on the old rotors was the same or not.

Here are a couple of pics:


Right side, not much wear


Left side, wear on top 3/4"


Another left side


The left side pics show the wear on the top 3/4", not a very even wear pattern. Does not seem like it would cause the grinding that I am experiencing. Does it look like a caliper problem?
Really not that bad of a wear pattern, can't see where that would cause grinding

 

I do not have pull from either side when braking. I would think that if I had a caliper problem I would get pull from one side or another. It brakes straight, just grinds.

 

(800)Car-Talk

 

Hmmm. You seem quite knowledgeable and apparently have done a lot of thinking on this.

As you indicate, it appears the pads on right side are making full contact with the rotor while the wear pattern on the left rotor suggests more localized contact on the outer diameter. Considering the different wear patterns I’m surprised that it doesn’t pull when braking – but have experienced weird things before – LOL.

Looking at the left rotor, the machining marks are still visible on the inner diameter, which seems to indicate little or no clamping force in that area when the brake is applied. This inner diameter minimal wear pattern is consistent with the normal brake-off drag that all disc brakes system have. It appears that when applying the brake, the left side pads are cocking around a little and are only clamping on the outermost area of the rotor.

Any chance the left caliper mounting bracket is incorrect or bent? Since you have replaced the rotors, calipers and pads and have accomplished nothing, I’d have to think the problem is somewhere else, perhaps in the mounting or you may have incorrect parts for this model. Who knows what a previous owner may have replaced?

Send me a private message if you want some help. I am a retired auto guy wintering (bored) just across the bay from you here in Gulf Shores, AL and will come over and take a look if you want me to. Not that I know everything but between the both of us, pretty sure we will be able to solve the problem.

Jake - -

 

my 90 made a grinding noise when one of the anti rattle clips broke on the caliber. I replaced the clip and all is fine.

 

Is it me or does that left rotor picture look like it's had some metal-to-metal contact on it? Is it possible something like the wear indicator tab is bent and making contact with the rotor? Just a thought.

 

Not a Corvette expert and am grasping at straws here but let me toss out some additional comments – it may trigger some new thoughts from you.

Does the inside of the left rotor face have a similar wear pattern? If not, then as others have posted, there might be something trapped between the rotor face and the pad – again, like an anti rattle clip. What is the wear pattern on the pads? While 100% of the pad should be in contact with the rotor it is common for the rotor to extend a slight amount beyond the outer circumference of the pads.

Looking at your pics, it appears the pads are making contact with the extreme outside radial edge of the rotor, both left and right sides. My Corvette is very distant so I can’t see if mine is like this or not, but the disc brakes I’m aware of have a very thin ring of rust on the outer radial rotor face which the pads do not touch. I checked a few cars around here and all have this rusty ring at the outer circumference of the rotor. After a while, this “rusty ring” on the rotor will capture the pads and that’s why the pistons have to be compressed in order to remove the calipers.

Having said that, your rotors appear to have a chamfer/relief on the outside edge so this might not be applicable here.

Any chance your car has a heavy duty brakes and the rotors are just too small in diameter? Have the mounting brackets positioned the calipers too far out from the rotors?

This is not rocket science so surely your problem has been seen before. Hopefully others more knowledgeable than I will chime in with the answer. Again, not a Corvette expert and obviously I tend to over analyze everything.

Keep us posted as to what you find.

 

I'm not familiar with that caliper. How does it mount? What does it slide back and fourth on? (Slide pins in rubber?)

Reason I ask is I've seen worn caliper hardware cause grinding noise to transfer to the passenger compartment. The rubber on the slides acts as a dampener to keep the noise/vibration isolated to the caliper.

Worth a look and it also may explain the kind of odd wear on the rotor.

 

I had the thought that the mark looked like it is about the width of the wear indicator, so you beat me to posting about it.

I suggest taking the pads out of the caliper to see what's up.

 

Great minds think alike

 

Is it possable that wheel is out of balance, or bent rim
Joe

 

Okay, visiting this again. I have replaced the front wheel bearing hubs, that was not the problem, but I don't regret doing it since the others were 19 years old, it did not hurt anything other than my wallet. I was thinking about removing the brake pads one wheel at at time, driving it to see which is grinding. What do you think, what is the down side to trying this? I know this is dangerous, I have thought that part out, will the pistons reach out as far as the rotors without pads, I would think not.This problem is driving me crazy, and I am going to fix it. If I can isolate the wheel causing the grinding, It will help me a lot.

 

Don't drive it without the pads in place.