my car has horrible ....horrible brake judder

my question is if i change my brakes to aftermarket ones will the brake judder stop??

-J

 

That's the idea for the most part. Stock brakes on most cars have a tendency to suck a$$. I have noticed that on mine as well. I am working on getting some Powerslots and Hawk pads from a "connection".

 

hook me up with that connection too

-J

 

Yeah, I gotta make sure I can get hooked up through the connection... Just to give you an idea...he got four rotors with hawk pads for $150...think about what that would cost normally...hopefully I can get that hookup.

 

hell yeah man that woudl be great i get second dibs behind you if possible let me know thanx bro

-J

 

If there's one thing I want, it's an AUTHORITATIVE consensus on the brake judder problem. That means, a well traveled, well defined strategy for switching out the OEM brakes (or upgrading them with a new part number, which DAVEB tells me they have.. new part# for rotors and pads, which he's now using and says they've worked well), and more specifically, a strategy that WORKS as close to PERFECT as possible.

e.g. Powerslot rotors or Brembo blanks... have ANYONE who bought these EVER had judder come back? Are these rotors truly our savior?
Big brake kits... I assume these remove recurring judder (under normal or somewhat aggressive driving) 100% in all instances? Does that expose the idea that 2K-2K1 brake judder is caused by the rotors being too small, and incapable of dissipating the heat generated?

 

Actually, on second peek, the originator of this thread is driving a 2K2, which implies that 2K2 and maybe 2K3 is also susceptible to this problem?

 

My 02 had brake judder when delivered .. I *think* they replaced the rotors. It came back, and I procrastinated until about 22K ... they resurfaced the rotors and left the original pads ... the judder hasn't come back.

This is a good link about what causes judder, but it doesn't give a specific remedy for our cars:
http://www.stoptech.com/whitepapers/...otors_myth.htm

 

I put Brembo blanks on w/ metal matrix pads and still have to turn them at LEAST every 12K. And thats after just putting up with the judder for a few thousand miles.

Of course I drive my car the way I ride my bikes - like a complete ***. I'm always slamming on the brakes. If I drove a little nicer - it might not be as bad.

 

Read that stop-tech article ... you MIGHT be able to avoid the buildup if you go through a break in after you turn them next.

When you turn them, are you taking much off? Will a brake shop turn them for you if you bring them in?

 

I like that article... read it before. Basically, the bottom line:
Properly breaking in your brakes is CRITICAL. After a resurface, you must break it all in properly.
Also, proper alignment of the pads against the rotor is critical as well... if the pads are pushing on the rotor in an uneven manner it will cause problems.

But, given all else is good, all the "thickness variation" or "material transfer" problems rely on one condition--HEAT.
If the rotors aren't dissipating heat fast enough, the "bad stuff" is going to happen. Or at least, it is more likely to happen than if heat were dissipated faster.

 

I'm not sure how much they take off mine when I bring them in, but I bring mine to a machine shop... actually it's a NAPA Auto Parts with a machine shop in the back. Takes them around 1 hour to do the job, 'cause their machine is slow as ****... but it does the job well.
Only thing I'm concerned about, is small grooves in my pads which remain even after I've resurfaced the rotors... (like very tiny grooves in the pads), is there something I should be doing to remove those? (although I'd dread sanding them, since what if I sand them at a certain angle and make the pads crooked... that'd cause more problems faster)

 

Since you're doing the brakes yourself (except for the turning) maybe it would be worth putting on new pads, and trying out the break-in process in that article? What pads are you using, how much are they, and how much does the machine shop charge?

I don't think sanding would be a good idea at all.

The groove might not be a problem, though .. the rotors are supposed to be much harder than the pads.

I also have to wonder whether having thinner rotors now (since they've been resurfaced) is allowing the heat to get through to the center, and then disappated? When the rotors were new, the heat might be higher, and causing problems with the pad? Just a wild guess, I admit. It could also be that I haven't been driving as hard lately.

 

Actually, thinner rotors can't hold/dissipate heat as well as thicker rotors, so the problem SHOULD get worse as you resurface the rotor. I've only resurfaced my current rotors once.

Pads are currently Raybestos QuietStop, with Raybestos rotors (OEM-like).

I'm still up in the open as to my next brake-related strategy. I am curious about the new Nissan rotor part#... specifically physical differences between it and the original. If it really does fix a good bit of the heat-related issues, I may try a pair of these with some performance pads (since I, uh, do "spirited driving" a lot... or at least encounter spirited braking, like when *******es stop in front of me on the highway during rush hour)

 

BTW, the machine shop charges $10/rotor... so it's a $20 job.

 

I was thinking about this and they should dissipate heat faster, though not hold heat as well. You have the same surface area (nearly) for a reduced mass. Sort of like a crushed ice cube melting faster then a whole ice cube. After reading the article, it makes even more sense for racers to have carbon/carbon brakes, where the material does not breakdown at superhigh temps as the brakes don't have time to cool.

This could be all BS, but I think we need someone who has done lots of study of Thermodynamics to get a good answer.

 

My understanding has always been that OEM rotors suck and will warp easily, but replacing them still will not solve world hunger. The rotors are basically too small for the weight of the car so they will still warp but not as bad with aftermarket rotors.

Bottom line is its $20 to $30 bucks to have them resurfaced so if I have to take them in every couple of months...so be it.

If I get cross drilled next time will that make a HUGE difference?

 

Cubano, cono, why dont you ask me these things ?........I will hit you up on AIM 2morrow !

 

Actually, you have a point, however it only suggests that I change my idea around a little-

Thinner rotors shouldn't dissipate heat any faster than thicker rotors. Dissipation of heat has more to do with available cool air passing through the vents.
However, rotors with more mass (i.e., thicker rotors) can hold more heat energy before rising in temperature.

These numbers are mostly bull****, but they illustrate the point (which I did learn during the "thermo" part of CHEM-105 in college)-

Thin rotor, i.e. rotor #1, say it's 15lbs.
Thick rotor, i.e. rotor #2, say it's 30 lbs. (complete BS but it illustrates a point)

Say a particular braking run (from, I dunno, 100mph to 5) produces 5 kJ (kilo joules) of heat energy. Note that is an absolute quantity, not a rate... there is 5 kJ of energy produced.

Rotor #1 rises in temperature by 900 degrees F.
Rotor #2, since it has more mass to absorb the heat, only rises in temperature 450 degrees F.

Temperature is roughly an average of heat energy per unit of mass... with the "specific heat capacity" of that substance taken into account (i.e., water can hold more heat per unit of mass than steel, I believe, before rising in temperature--that is the main reason why water is used as a coolant in a lot of things, such as engines... it can hold a LOT of heat energy per unit of mass)

Moreover, in the case of disc brakes, the surface area of the pad can have influence on the thermal performance. With a larger surface area on the pad (wider rotor diameter + bigger pads), the heat transfer can be spread out further, effectively causing each square centimeter of pad surface to operate a little cooler than before... further reducing the likelihood of material transfer (due to localized hot-spots).

If any of this is wrong (not the numbers, but the concepts, especially the part about the pad surface area) please chime in and correct me.

So addressing the problem can be done in two ways:
1. Properly bedding the pad so it's not as likely to transfer material to the rotor
2. Changing out the rotor and possibly pads to a cooler design, so the system never encounters the extremely high-heat conditions which cause these problems to begin with.

Ideally a combination of both 1. and 2. should solve the issue completely. I would be confident that a Big Brake Kit could solve my problems completely, unfortunately they're rather expensive and the better ones won't fit the stock 17x7 wheels I have... (and I am not upgrading, at least not beyond 17" diameter wheels)

 

Here's the link that can help with your concerns of a Big Brake Kit that can be used with your stock 17's. My car is the test bed for the two kits Matt is/has put together. We fit the 12.6" rotors with stock 2k calipers behind the stock 17's, and it cleared. Specifically look at post #56 and look at the pics he has the link to. FYI, I've had the kit with the 300ZX TT calipers now for a few weeks and 500 miles, and they are awesome!

http://forums.maxima.org/showthread....1&page=2&pp=30

 

Excellent--I'll check that out in a bit (@ work right now... bookmarked the page)

So do 300ZX TT calipers work with stock 17x7's, or should I read the thread before asking that Q?

 

You SHOULD read that thread, but I'll answer that one as a quick "no".
I'm working on making a bracket to fit the stock 5th gen calipers over the 6th gen rotors currently.. should be done in a couple weeks ( as soon as I get more parts in that I ordered)

Once I have that done, I'll also look at custom making a 2-piece version of the same rotor, and some aftermarket calipers for a more hardcore kit. There are a lot of people wanting something that will fit under the stock 17s, but no aftermarket kit will (so far).. It's my goal to get something out fairly soon to alleviate that issue.. I don't know if I will be able to do a 4 piston caliper simply due to clearance issues, but I can do at least a 2 piston one, which will be much better than the OE calipers..

 

Cool, just read through the thread. Good deal.
I'd be looking for pricing for a kit including 2k4 rotors, and the adapter bracket kit (bracket + bolts/nuts/etc.) alone (got stock 5th gen calipers and SS brake hoses already installed in the stock setup)