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Dinosgt

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Just installed racing brakes rotors and pads and went through the brake bedding process.

One thing I've noticed (besides that they are noisy as hell) is that the rears don’t seem to be bedding correctly. The face of the rotor should be showing about 41mm of surface where the coating is removed, but I only get about 3/4 of that.

Pads look to be the same dimensions as stock. Calipers were working fine before with the stock stuff and showed correct depth of rotor face contact as far as I can tell.

Any thoughts?

IMG_8499.JPG



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Mojo88

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So you're saying the pad width is 41mm, but it appears that only about 30mm is contacting the rotor????

I would start by removing pads in the 'affected' areas and looking at the surfaces of them, to see if they look like they are wearing all the way across.

The rotor surface looks odd. Maybe it's just the photo, but there appear to be streaks on the rotor.

Anyway, the very first item on the "to do" list would be to carefully remove the caliper and pads, triple-checking the installation as you go along to confirm that it was done correctly, it's VERY easy to make small mistake, just ask me, haha. Check pads carefully for even wear. And also, look closely at the caliper. Is it the right one for the new parts? Is it mounted correctly? As we all know, sometimes adapter kits (and/or customization) are needed for proper fitment of aftermarket parts.

And sometimes calipers can be installed improperly aligned, I saw this on my Roush Mustang that I purchased last year. Left rear brakes were wearing oddly, so I took apart and found caliper mounted crooked!!! I would have thought it impossible to mount a caliper cockeyed like it was, I was amazed. Never saw anything like it, and I've been doing brake jobs for 40+ years.
 
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SVTdreamin04

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Just had a buddy who put rear pads on his truck, and had the same thing. The pads were defective. They weren't a big name auto parts store branded pad either. I think they were Raybestos.

Anyhow, he tried a different brand, which solved his problem.


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Dinosgt

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So you're saying the pad width is 41mm, but it appears that only about 30mm is contacting the rotor????

I would start by removing pads in the 'affected' areas and looking at the surfaces of them, to see if they look like they are wearing all the way across.

The rotor surface looks odd. Maybe it's just the photo, but there appear to be streaks on the rotor.

Anyway, the very first item on the "to do" list would be to carefully remove the caliper and pads, triple-checking the installation as you go along to confirm that it was done correctly, it's VERY easy to make small mistake, just ask me, haha. Check pads carefully for even wear. And also, look closely at the caliper. Is it the right one for the new parts? Is it mounted correctly? As we all know, sometimes adapter kits (and/or customization) are needed for proper fitment of aftermarket parts.

And sometimes calipers can be installed improperly aligned, I saw this on my Roush Mustang that I purchased last year. Left rear brakes were wearing oddly, so I took apart and found caliper mounted crooked!!! I would have thought it impossible to mount a caliper cockeyed like it was, I was amazed. Never saw anything like it, and I've been doing brake jobs for 40+ years.


Thanks very much - Ill tear it apart today.

Yes - I am saying that it looks like only part of the pad is wearing on the rotor which is given by the lack of the black coating being removed across the face evenly by the pad. Either the pad is wrong (but looks to have the same dimension as the OE) or the caliper is misaligned and not applying pressure across the face evenly.

I am with you...I am not sure how the calipers could be installed wrong since they are so basic (they are the stock caliper), and its wearing exactly the same (but incorrectly) on both sides of the car. I see the streaks as well, which lead me to believe they are not bedding right. Maybe I am not applying a hard enough pedal?

Curious - how were the installed wrong on your rouse? There really isn’t any play in the mounting holes for them is there?

The fronts seem fine, but I notice that they don't seem to be transferring material as evenly across the face as I would like, but maybe that will change with wear in.

Will share results once I tear it down again.

Thx again
 
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Dinosgt

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Just had a buddy who put rear pads on his truck, and had the same thing. The pads were defective. They weren't a big name auto parts store branded pad either. I think they were Raybestos.

Anyhow, he tried a different brand, which solved his problem.


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Thanks for your help - I am using the RB street pd, which should be OK, but I ordered new OE pads which seemed to wear fine (they only had 10K miles on them when I took them off) and were nice an quiet on the street - so I may end up going this route if I cant resolve the issue.
 

Mojo88

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.....Maybe I am not applying a hard enough pedal?

Curious - how were the installed wrong on your rouse? There really isn’t any play in the mounting holes for them is there?
...............

'Bedding' requires a pretty hard pedal, just to point of locking up wheels, and repeated a few times. EBC brakes is procedure I use. Here's an article on it from EBC: https://ebcbrakes.com/articles/bedding-in/ (this procedure might not be applicable to your particular setup)

Regarding my Roush and the crooked caliper, I installed new pads, using the original caliper and rotor, it went together perfectly. And then I kicked myself in the ass for not paying attention to what had actually caused the issue in the first place. So it remains a mystery. But suffice to know that it can happen!
 

PaxtonShelby

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I would reinstall the original pads and see if they make better contact with the rotors. If so, the new pads are your problem.
 

biminiLX

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Hey Dino do both rears look the same? Uneven outside wear on both sides when both insides have full pad contact?
-J
 

Dinosgt

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Ok folks - ripped it apart and you can clearly see where the outer pad is not contacting the rotor. Compared to the innerpad, it’s obvious.

When I spun the discs inside the pads before removing them they made rubbing/scrapping sounds, but I see nothing interfering anywhere.

Outer pad

IMG_8541.JPG


Inner pad

IMG_8543.JPG


Both rear sets compared to stock pads which were on stock rotors.

IMG_8531.JPG


I noticed the inside of the calipers were it grips the outer pad has some funny wear. I’ll try to clean that off and try again

IMG_8540.JPG


Just to confirm - the pad with the little dog leg sticking out is an inner pad, and the dog leg goes to the rear of the car correct?


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Dinosgt

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Last question - why do the stock pads have chamfered edges? The new ones don’t. Any benefit of them, other than the disbenefit of less pad/to-rotor surface?
IMG_8545.JPG



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Mojo88

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Is it possible the pads are manufactured with a little extra thickness at the top? I would measure the thickness with a dial caliper just for the heckuvit. I would assume they should all (all four) be equal thickness.

Then I would mount pads back (carefully) and put it all back together on one side and eyeball the edge of the pads in relation to surface of the rotor. If something seems cockeyed, then you need to figure out what it is. If everything seems parallel and straight, then this may just be "normal" wear until the pads get some miles on them.

Both sides are doing it, so I am kinda leaning towards this could be "normal" for this setup. But it is odd that the inboard pads are perfect while both outboard pads are not fully contacting the rotor.

Again, double and triple check your assembly. Make sure nothing is binding. I have seen numerous times where I needed to file casting edges off the pads to prevent them from binding. And be sure the sliders and abutment clips (not sure what you have on that caliper) are in correct places, seated and lubed properly. And if still stuck (or no answers here) then call vendor where you got the parts, or better yet, call the manufacturer directly and email them pics.
 

Dinosgt

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Thanks. I will look at everything closely. Also bought a set of stock pads. These have no shims or other noise abatement stuff, which I think might help the stock pad stay more square with any variations in the caliper casting.




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StrayBullitt

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@Dinosgt how many street miles have you given the new brakes total? It looks to me like you just haven't quite driven it enough and the pads are not fully seated in and don't have full contact yet. I'd probably give it a few hundred miles before you worry. You have to have pressure on the inside pad before your caliper clamps and pulls the outside pad onto the rotor.. also when this happens the caliper tends to want to flex a little so to speak, or deflect because the outside of the caliper is just floating, it's not fixed to anything. I bet if you had the wheels off the car and had it on stands, if you had someone push the brake pedal for you, you can probably see it happen.

I would pull the caliper pins out and clean them up really well and grease so they move really easily if you didn't already, put everything back together and give it some more miles. I believe the chamfered pad edge is only for noise reduction, less likely to squeal, not really a major concern of a high performance pad manufacturer, but definitely for an OEM.
 

Dinosgt

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Thanks much. You may be right -I only have about a hundred miles on them. I just didn’t like the wear looking odd on the rears so I ripped them off for inspection.
Even tho RB recommends no shims or other anti noise stuff, All the brakes made some noise while running , as well as quite a bit during braking (ok with race pads, but not street) I decided to buy some stock pads just in case I couldn’t get them right.

I also noticed the fronts made more noise on hard turns with no braking so wondered if they may be vibrating funny in there as well. Maybe greasing the pins up front could help.

Thanks.


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StrayBullitt

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When you say noise.. do you mean like a rough.. (almost kind of a harsh road noise type of sound) ? If so, there is a good chance that will subside as well once the pads are fully seated and broken in.

From my exp. keeping the caliper pins nice and clean and lubricated helps keep the caliper clamping correctly and that keeps the outter pad in good contact to the rotor.. But Probably not so much related to any type of noise that you may be hearing.
 

Mojo88

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You have to have pressure on the inside pad before your caliper clamps and pulls the outside pad onto the rotor.. also when this happens the caliper tends to want to flex a little so to speak, or deflect because the outside of the caliper is just floating, ......

I agree this would be accurate on single or dual piston caliper, and I had same thoughts. But it looks like OP has a 4-piston caliper, so flexing should not apply??? Just sayin'. Not trying to bust your chops at all. You guys that race may be experiencing flexing even with 4-piston calipers, I dunno... I don't race.
 

StrayBullitt

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Our 5 hundos rock a single piston rear :(. I believe OP mentioned still on stock calipers. I think everything in question in terms of pad contact is with the rear..

I am liking the looks of those rotors.. I'll be interested to see how you end up liking this setup after some more street use.
 
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