Brembo 4 piston users....

[gcassidy]

After running Summit Point last weekend, I was swapping back to my street pads today, and noticed a weird pattern on my driver's side rotor. Since they were new, I was wondering where it was coming from, especially since the pass side was fine.

Here's what I found. Anyone ever have this happen? There's a little allen screw that it looks like I need to tighten after removing the caliper.

Scallop pattern on driver's side...

Normal on pass side...

Looking down through caliper...

And up from underneith...

 

[Maynor]

Never seen that pattern on my rotors Greg. I'm running the same Brembo 4-piston setup and calipers and I was at Summit Point about a month and a half ago.

Best Guess right now, hub flex combined with a fixed caliper is a partial cause? Did you notice any pulsing in the pedal?

 

[ac427cobra]

Those steel wear pads prevent the backing plates from wearing out the aluminum caliper casting.

I have abused the crap out of my original Brembos and have never had those screws come loose? :shrug:

I'd put them back in with one drop of red Loc-tite permanent thread locker on them.

FWIW

:thumbsup::coolman::beer:

 

[gcassidy]

John, I think its coming from the clip rubbing on it.

That's what I was thinking Bruce, but with blue loctite.
I guess this is a "Here's another thing to look for after a track event" thread. :lol1:

 

[ac427cobra]

John, I think its coming from the clip rubbing on it.

That's what I was thinking Bruce, but with blue loctite.
I guess this is a "Here's another thing to look for after a track event" thread. :lol1:

The blue loctite can't take the heat the red stuff does. Besides, the chances of having to replace those pieces are slim and none.

I don't know about you, but my calipers get hot on track! ;-)

 

[LargeOrangeFont]

Agreed. Blue would be useless for that fastener.

 

[gcassidy]

OK, red it is.
Thanks guys.

 

[BlackBolt9]

I've seen that scallop pattern in rotors before. Not sure what causes it but I've never seen it be a problem from what I can remember. I would guess that the "clean" shiny ring through the middle of the scallop pattern was caused by the loose clip.

Not an expert but that's my opinion.

 

[gcassidy]

Here's what I found upon removal of the caliper.

The screw had backed out and both it and the metal shield were contacting the rotor. As I suspected, that's where the pattern was coming from. I don't think there's any damage to the rotor, but the screw just barely survived.

And I think I did also. I'm trying to think what would have happened if the screw had come out more, which would have happened with more track mileage since the rotor was basically wearing it away. I don't know if there could have been brake lockup if the clip had come out, but I'm lucky and grateful I didn't find out.

I'm going to remove all of the screws, and put red loctite on them.

 

[gmsux]

Maybe change the dust boots too while you're in there!

 

[ac427cobra]

Maybe change the dust boots too while you're in there!

I'd pull them off altogether! :idea: They are just going to fry on the first outing anyway!

 

[brkntrxn]

I have seen that scalloping effect on my buddies 07 350Z and another buddies 03 350Z. Both have stock 4pot Brembo calipers and they run XP10 and/or XP12s from Carbotech. We had chalked it up as pad deposits.

Maybe I will show this to them and see if their clips are loose... but I doubt it that is the issue.

 

[Sloe Truk]

I have seen that scalloping effect on my buddies 07 350Z and another buddies 03 350Z. Both have stock 4pot Brembo calipers and they run XP10 and/or XP12s from Carbotech. We had chalked it up as pad deposits.

Maybe I will show this to them and see if their clips are loose... but I doubt it that is the issue.

Kev, I guess that you are referening me

To me it looks a lot like pad smear and the pulsing pattern on the driver's side looks like ABS pulse. What kind of compound were you using? Also what type of fluid and how old is/was it?

I have seen that on my Brembos, but it is generally from overheating the friction material (as far as the smearing) and the pulsing honestly looks like air in the hyraulics. I would look at stepping a level in aggresiveness on your friction material. As far as the pulsed pattern, I would start with the basics, a good flush with good fluid. As far as the loose bolt, I really doubt that caused the pattern, those brakes would have chewed though that little bolt and plate and never noticed it, imo.

 

[gcassidy]

Naw, I think the pattern is from the metal clip and screw rubbing against the rotor. Hence no pattern on the pass side.
I only mentioned the pattern because that's what started me looking for something else.

FYI: Brembo solid rotors, Hawk DTC70 pads, new Wilwood fluid, and cooling ducts.

 

[brkntrxn]

Bryan,

When you and Mo have those patterns, it is on both sides, correct?



-Kevin

 

[Sloe Truk]

Bryan,

When you and Mo have those patterns, it is on both sides, correct?



-Kevin

I either smear one corner or all four, depends on driving style. If it is VIR then I generally smear the friction material on the left front, due to all of the trail braking I do, CMP and TGPR I generally smear all four corners due to the generally aggresive braking I do there.

O.P. Wsn't trying to step on you or your findings, just trying to share. I do see some minor scalloping on a few veins on the the passenger's side rotor in your pic, no where are severe as the drivers side.

 

[gcassidy]

No prob. And I agree with you there are some generic patterns on both rotors (I guess they're like people, everyone's different-lol).
But the pattern I was seeing in my driver's rotor (and which isn't coming out as well in the pic now that I look at it) is definitely from where the clip was being worn away. I was matching it up when removing it. It's not deep enough to do any damage, I can't hardly feel it with my nail. And my guess is the scalloping pattern is from the clip bouncing back and forth from one side to the other while rotating on the screw. I swear I wish I ran a camera on my brakes sometimes.

 

[BlackBolt9]

EDIT: Nevermind, the confusion/argument seems to be coming from the fact that we are using the term "scallop" to desribe two different things.

I was using scallop to desribe the light and dark wavy pattern around the rotor. It appears gcassidy is using it to describe the marks on each side of the shiny ring in the middle of the rotor. (I would have called them grooves not scallops, damn the english language and it's many words of description )

 

[Sloe Truk]

No prob. And I agree with you there are some generic patterns on both rotors (I guess they're like people, everyone's different-lol).
But the pattern I was seeing in my driver's rotor (and which isn't coming out as well in the pic now that I look at it) is definitely from where the clip was being worn away. I was matching it up when removing it. It's not deep enough to do any damage, I can't hardly feel it with my nail. And my guess is the scalloping pattern is from the clip bouncing back and forth from one side to the other while rotating on the screw. I swear I wish I ran a camera on my brakes sometimes.

I agree, I'd love to a camera on my headers and my brakes. I have no doubt that my EGTs are as hot as any turbo car.

 

[Todd TCE]

Late to the party but yes; that "splotchiness" is pad smear from a pad and use combo that are not happy with one another. The pads are reaching a critical point where they are breaking down from over heating.