Still Can't Solve Brake Judder
 

Sorry for yet another brake judder thread. I just can't seem to shake this issue.

I thought maybe my winter tires were causing the problem, but I've ruled them out. I indexed the rotors and was fairly smooth at the beginning of this year. Now I have a pretty bad judder and haven't had my winter tires on at all while the judder developed.

I've just now switched to my winter tires and I checked the run out. Both rotors are right around .001. I just don't get how I can have judder with such a low run out. When I spin the tires off the ground I can hear the pads rub unevenly. So it makes sense that I have the issue, but not sure what could be causing it. I checked the from the outside in. As expected, the run out lowers as I get closer to the hub.

Here is a pic of the rotor and runout dial at it's max from 0:


https://cimg9.ibsrv.net/gimg/www.myg...7aa195e7b6.jpg


Condition of rotor with serious judder.


https://cimg0.ibsrv.net/gimg/www.myg...2b2ac3d509.jpg


Run out right below .001.

Any insight would be greatly appreciated. Or new rotor/pad suggestions. I'm currently running a pretty basic setup. Centric standard rotors (12142100) C-Tek Standard. And Centric(10513460) Posi-Quiet Ceramic pads.

Thanks in advance!

I think you identified the problem.

Replace the pads, turn or replace the rotors, have the wheels balanced and get an alignment.

Just my $.02

Telcoman

I see you were also having these issues back in this thread
https://www.myg37.com/forums/brakes-...ke-judder.html
That is very minimal runout, I have judder w/ my Wilwood setup too w/ street pads, haven't measured the runout (hopefully I'll have a Dial indicator under the tree next week) but there is slight high point when I free spin both front wheels :(
I'm going to take a good wire wheel to the hubs see if it gets better. Frustrating for sure!

May not be a result of runout but of uneven pad deposit on the rotors. I'd try steel wool or very fine sand paper then do the bed in again.

I had a brake judder issue with stop tech street performance pads and centric premiums. Had them resurfaced and swapped to posi quiet pads and have had zero issues, less dust and no noise.

I had the brake judder issue. Then one time I had a panic stop from about 30 mph. That solved the issue.

I checked the from the outside in. As expected, the run out lowers as I get closer to the hub.

as stated in your own post. so what is the runout towards the edge of the rotor? i can see from the pic that the outter portion of the rotor looks glazed. in addition did you mic the rotor at least at 6 different spots to check parallelism? if you wanna go cheap resurface the rotors and slap some akebonos or oem dealer pads on it. the pricier route would mean changing the rotors and pads.

Wire wheels and odd angles lead to even more frustration. Considering how many brake pad/rotor jobs I do for friends and family...heck I'd justify the cost even doing these tasks on just your own vehicle...

Look into ..
Scotch-Brite Roloc Brake Hub Cleaning Disc Kit, 07547

Kit is like $25-26 and if it tells you anything, I'm still on my first reloc disc and I've used it on 3 cars, 12 rotors total...nothing with extreme rust or anything. I'm about to be on my next disc probably when I do another car. Makes such short work of properly cleaning the hub surface to get a nice even face for the hub surface to mate to.


Brake residue build up is commonly mistaken for lateral runnout (aka warping)... with certain high dust/residue pads (like StopTech SS for example), it's good practice to do mini-brake pad break in routines in hopes of getting that residue off the rotor surface before it becomes an iron-carbide called cementite. Really, this all comes back to a proper bedding of pads to rotors that is often forgotten about or too late after the fact because the brakes seem to perform fine right after install for some people.

More from Centric on this topic of 'Cementite' and why even resurfacing rotors could be just a band-aid fix if you have this issue.

'The term “warped rotors” is frequently incorrectly used to explain the judder sometimes felt under braking, however, the iron used in rotors is almost impossible to physically warp because of its hardness and stability. Instead, the vibration is typically due to either an uneven transfer layer of friction material on the rotor face, corrosion resulting in an uneven surface condition, or by a prior unsuccessful machining of the rotor by a technician. A proper bed-in (see above) is essential to minimize the occurrence of this phenomenon.
A re-machining of the rotor surface might solve the problem temporarily, but it will likely return if there has been a conversion of the iron makeup below the deposit to cementite (also known as “hot spots”) - an iron-carbide. Cementite is harder than the base iron so when turned on a brake lathe, the harder deposit area will deflect the nose radius on the cutting tool and the high spot will still be present to a degree and the process of increasing deposit of new pad material over the high spot will re-start. Surface grinding of the rotor will produce a suitable result if the two friction surfaces are flat and parallel but there will still be areas of greater hardness. '

On my last car, this judder behavior would start to creep every year or so. When it got to where I couldn't take it anymore, I would bed in the brakes according to recommendation by Hawk (since I was using Hawk HPS pads and Brembo blanks.)
The proper approach would have been to clean the rotors and *then* bed them in, but this worked well-enough for me.

Keep in mind, different pad manufacturers have different recommendations.

The furthest out point was about .001 on the dial indicator. I checked at least 5 places from the very outer edge to the hub. The runout became lower as I got closer to the hub.

I did not mic the rotors. I'll have to pick up a micrometer. I usually change the rotors every other brake pad change so I never approached the minimum thickness on my cars. These rotors are new from 11/11/14 and only have 14,000 miles on them. I'll pick up a micrometer to see if I can find any variation in the thickness.

I've done the breakin procedure a few times. I use the Centric (StopTech) steps outlined on their site: 10 hard without ABS brakes from 60 to 10 mph. I've done it a few times, it seems to help a little with the judder, but it's usually back very shortly after.

AUR11, which posi-quiet pads are you using? I'm using the centric posi-quiet pads.

krazyfiend, thanks for the cleaner suggestion. I'll definitely pick that up. That's cheap enough in the grand scheme of replacing the rotors and pads.

I was going to replace my hubs a while back, but I just couldn't justify it considering the runout. I would be much more inclined to think it's the hubs if I couldn't get a close to 0 runout. I'll try cleaning the rotors and bedding in again.

For those that index their rotors, do you generally get a zero runout? Or are you between 0 and .001 like I am on my rotors?

I'll definitely try another brand of rotors and pads next time. I haven't had any luck with the StopTech brand at this point. Maybe Brembo blanks and Akebono pads... Anyone have luck with that combo?

I've been doing brakes since my old 86 Pontiac Sunbird, this really is the first car I've had a judder issue. The changing rotors every two pads has worked for me for years. Without indexing as well, I added the dial indicator to my arsenal of tools when I got this car.

Thanks for the input!

Well... IIRC .002 is within Infiniti's accepted tolerance and most rotor manufacturer tolerances to be considered...'good to go' (or sell, however some do state .001 and will replace ones beyond that)..

Pads wise, I had Stoptechs before and did not like how much residue they kept leaving on the rotors. Hawk 5.0's solved that issue and I will be getting them again whenever I'm due for new pads. Even with 70-80% life left on the Stoptechs I swapped out, it was well worth making the jumps to the 5.0s. So much better characteristics for my daily driving needs (that sees all the seasons as well).

Gave my rotors a good scotchbrite scrub down and re-bed, back to a happy judder free state :)
The wife does most of the daily driving on this car so it may be some habits there that need to be addressed????

i would definitely mic the rotor. i think you have a low spot somewhere on the rotor which is affecting the parallelism of the rotor as the brake pads bite into them. take at least 6-8 mic readings at different spots which the brake pad lining would actually contact on the rotor surface. as for specs go just google it and see what turns up. i don't think nissan has a specific brake rotor parallelism for these g's

Knock this all out at one time.

1. Rotors (new or machined)
2. Pads
3. Balance wheels

My bet is it is simply the rotors that are warped where you are not measuring. I would start there first then move on to the next. It happens. Rotors suck - but luckily, they are not an expensive nor difficult repair.