Nick's brake issues thread.

From the tranny down to wheel bearings.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby Nsquared97 » Mon Jul 30, 2012 12:39 am

AustinR wrote:I'm running now set screws in the front. Driver's side set screw hole is stripped out/rusted. Passenger side has a broken off set screw in it already. haha.
The lug bolts hold the rotor in place. I'd try it without the set screws.

Alright, going to go try that now then. Just wanted to make sure I wasn't doing something really dumb based off of something I thought I read on the interwebz lol.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby Yoshi » Mon Jul 30, 2012 12:56 am

FYI I don't run those screws
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby Nsquared97 » Mon Jul 30, 2012 1:14 am

Ran it again with/without the screw, no difference. I think I was just looking at it funny too, seemed to center just fine this time with the screw in.

Why don't you run them Yoshi? Are they there just to hold the rotor still while your trying to line up the wheel or is there some other purpose to them?
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby ss45466 » Mon Jul 30, 2012 1:31 am

The screw just holds the rotor while you line up the lug bolt. Audi's don't use them and it can be a pain to line them up.

Looks like you have a defective rotor after trying everything mentioned and with your old rotor the noise goes away.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby AustinR » Mon Jul 30, 2012 1:37 am

It's very strange. I mean, even if it's a "defective rotor"...what physically is making that noise, ya know?
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby Nsquared97 » Mon Jul 30, 2012 2:16 am

Just tried switching side to side. The problem seemed to go away, but it was back the 3rd time I got on the brakes, (on the left side of the car now, switched side when the rotors were switched) which is about how many braking instances it was when I first noticed it.

The ONLY thing I can see wrong with the rotor, is that on the inside edge, at the very inner diameter there are 2 spots that have a few nics in them. You can see where that ate just a little bit of the pad material at the very inner portion of the pad. Seems very minimal, but could that be doing it?

Also, I checked the thickness all around the rotor with my calipers and every measurement I took was within 0.0005" or 0.01mm.

I'm planning on calling Brembo tomorrow and seeing what they have to say. Hopefully they will let me return it and send me a new one. Pretty annoying, other than this issue the brakes feel great, much more bite and less mushiness in the pedal than ever before.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby ss45466 » Mon Jul 30, 2012 2:20 am

Can you take a pic of it?

It seems if there's material in two spots and it makes noise when they have warmed up you have found the problem.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby Nsquared97 » Mon Jul 30, 2012 2:34 am

My bad, I did take pics and forgot about them.

First 2 pics show the nics in the rotor:
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Next shows the pad, kinda hard to tell, but the very bottom of the pad right in the center, where the divide is between the seperate sections of material. Those corners are both wore down just a little bit.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby AustinR » Mon Jul 30, 2012 2:52 am

Dang...I cannot imagine those little nics making that noise but I'm certainly no mechanic.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby M20_fever » Mon Jul 30, 2012 4:02 am

I don't run the locator screws either. The ID machined surface could be slightly off center of the OD machined surface of the rotor causing it to wobble in the X direction. If you want to check, measure the hat wall thickness all the way around, you will see a thicker side and thinner side if the machining is off.
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Re: Educate me on brake pads Edit: New issue, any ideas?

Postby Yoshi » Mon Jul 30, 2012 12:19 pm

return and get a new rotor

I run studs so lining up the rotors is easy. Plus the calipers tend to keep the rotors on great once you do the brakes the first time.
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Re: Nick's brake issues thread.

Postby Nsquared97 » Mon Oct 15, 2012 12:42 am

So I guess this is just going to become my brake issue thread lol. So, my car has always had just a bit of a mushy pedal. Nothing terrible, but never as firm as I want it to be. That got a lot better after I replaced all the pads and rotors, but still some mushiness. More recently, I noticed this at the last autoX I did, the one hard braking zone we had the car just didn't feel like it was going to stop.

Anyway, Austin and I decided to flush the system today with ATE super blue to see if that would make any difference (I had been running Valvoline synthetic DOT 3/4 before). Did that, very few bubbles came out, but the fluid to the rears definitely looked nasty, like there was rust somewhere in the system. Could be the rear calipers themselves since they were not rebuilt whereas the fronts were.

While we were doing the bleeding, I noticed something. On Austin's car when we bled it, and really any other car I have bled, once you get the air bubbles out of the lines, if you pump the pedal about the 3rd pump the pedal is hard as a rock and will barely budge. On my car, it gets firmer, but there is still some pedal travel even after 4-5 pumps. Took the car out when we were done and the pedal still feels mushy, I think it's slowly getting worse. I guess I don't notice it much because I don't use the brake very heavily on the street, mainly engine braking combined with a bit of brakes.

So, what are your thoughts? I'm guessing master cylinder, but I always kind of assumed when those go, they GO, like no brakes at all. Would a bad booster have any symptoms like this? My guess is master cylinder, you can hear a sort of "pssshhhhh" come from that area of the car when you push the brakes, most noticeable when bleeding them.
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Re: Nick's brake issues thread.

Postby AustinR » Mon Oct 15, 2012 1:21 am

You should drive my car to compare. What time do you get out of work again?
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Re: Nick's brake issues thread.

Postby M20_fever » Mon Oct 15, 2012 1:57 am

master cylinder. They do get softer over time before completely failing, you just don't notice because it happens gradually. My buddy lost his brakes in his '87is at the track, couldn't get the rears to bleed at all, got some from the fronts but not much. Turned out to be the MC, so he ran and got one and we installed it at the track. It immediately made me realize how tired my MC was when we bled his new one. Night and day difference. I still need to replace mine, its on my winter project list. Mine feels like marshmallows compared to his new one.
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Re: Nick's brake issues thread.

Postby Nsquared97 » Mon Oct 15, 2012 1:59 am

Sounds like I am going to be replacing mine in the near future then. How bad of a job is it? I am guessing not terrible if you guys did it right at the track.
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