Charley Hoyt

I attended a driving school at Willow springs last week and my car started making a metal to metal scraping noise under braking. I assumed that I had a pad failure or that I had burned through the pads.... But when I took it apart the pads were fine and it looks like the rotor is scraping against the brake caliper mounting bracket. Everything in th suspension appears tight. The only thing I can think of is that my bearings are going bad. Has anyone else experienced this?

VetteDrmr

It could be, you didn't say whether it was a front or rear rotor that was rubbing.

Charley Hoyt

It is the front left wheel.

Solofast

Take the caliper off and then the brake disk and inspect the hub and bearing. Could well be the hub is cracked and the only thing holding the thing on is the caliper.

Wouldn't be the first time.

Bill Dearborn

Did you check the hub by rocking the wheel up and down with your hands at the 12 and 6 positions? Seems like something that is allowing that much rotor movement would also allow the complete assembly to rock up and down a lot.

Bill

Charley Hoyt

Yes, I tried rocking the wheel up and down but there wasn't an noticeable play. I assume that it takes more force than that to make it deflect. I haven't taken the rotor off yet.... But I will before I drive it.

moespeeds

Check the hub bolts as well. Mine came loose and showed similar symptoms.

Charley Hoyt

Thanks, I will check them.

fatbillybob

Sounds like you are on the right track Charlie. Buy the SKF hubs and consider replacing the other 3. We breaks the stock hubs on track especially with sticky tires. This is a known issue. Van Steel and hardbar sell the hubs maybe pfadt too. Hardbar loves the nordlock and hex bolts but they really are not necessary. The hex bolts are a nice conversioon however makes it easier to trackside service and the T55 size iirc is not that hardy when you have some age and grime on those old bolts. A nice air tool makes your life a lot easier when you do this job and the cheapo harbor freight ball joint remover kit works great!

k24556

If the caliper bracket is contacting the rotor, then there should be some damage on the bracket as well, from any contact. I would expect to see a groove, though, not smearing. Were the pads bedded (broken in) properly?

From the apearance, it looks something like what i experienced, a ball of rubber got thrown there and smeared on the rotor. when it happened, my ABS went nuts on hard braking in a braking zone.

Charley Hoyt

Thanks for the advice Carl. It looks like some SKF's are the way to go. A couple of years ago I purchased a Kent Moore ball joint tool that works great. But why do the ball joints need to be removed to change the hubs? Is it a clearance issue?

Charley Hoyt

In the picture it looks like pad smearing but it appears to be metal to metal scraping.

froggy47

There is one ball joint fastener hiding behind the lower ball joint, basically impossible to get a wrench on without popping the ball joint. Ball joints = easy with the HF or KM tool.

I did a video, click below, on using the tool. Search YouTube channel.

moespeeds

I second Froggy's video. Helped me through it when I did ARP long studs on all of mine. I safety wired my hub bolts, though it's overkill for sure. Red loctite won't hurt. If they are a problem coming out later (they won't be) just add a little heat. You basically can't check the lowest bolt once the hub is back on, so I wanted the peace of mind since mine came loose on track and I lost the brakes.

k24556

If it is metal to metal what other piece of metal shows wear? that will give you a clue as to what is causing your problem. Usually metal to metal does not discolor, and you see fresh exposed and sometimes really rough gouges. All I'm suggesting is SKF hubs are $350 each and if the original isn't bad then replacing them won't cure your problem.

With the caliper off, that bearing should be as smooth as butter. The bearings get rough feeling long before the clearances open up. If the bearing is smooth and there is no visible wobble, look somewhere else. Did you put fresh brake fluid in before going, if not, maybe you boiled on one side and you now have air bubbles (on the other side so this one bites more for the same pressure. Also, if they are stock pads which I suspect they may be, you may have just overheated the pad material. That is what it more looks like vs bearing clearance.

I still think there may be some transient material, a rock or something like that that got inside and made that mess.

Charley Hoyt

The bearing didn't feel rough. I am going to take the bracket off to see if I can confirm if it is what is rubbing. The pads are Carbotech XP-10's. I put new fluid in right before taking it to the track...But I will bleed the brakes because my pedal got VERY soft while at the track...but, I am not sure how that could cause this. I also checked for material stuck in the pads and nothing is there. While driving I can hear metal to metal scraping when the brakes are applied fairly hard. I am also going to check to see if there are any issues with the Caliper bracket or the mounting bolts.

taken19

What tires are you,running? With PS2's, I was on the verge of smearing XP-10's on stock Z51 calipers. As soon as I stepped up to Hoosiers, they were thoroughly melted onto the rotor. The pics look very similar to what I was experiencing while on PS2's. it could be that you are out-driving the XP-10's.