I have stock rotors and pads( rotors have been devoloping minor cracks on them for a while.... i guess its time to change).


I been to the dealer a few months ago and complained about the brakes stopping funny.

When i slam on the brakes in wet/rainy conditions, the brakes feel like they are barely working.

The car stops, but not all the way. Feels like when you slam on the brakes the inital contact or bite of the pads slow the car down, but when you press on the brakes hard, the car doesnt stop like it used to.


half a year ago i changed my stock pads to mintex. The stock pads were worn down. I havent experienced, the above symptoms with the original stock pads.

I thought the mintex pads were the problem, since especially in wet conditions the car suffered from the above symptoms.

I then switched back to new oem stock pads, and the problem continued. I then took the car to the dealer and they said that my rotors were glazed. I guess they deglazed them and the car finally stopped really well. (this was around August)

the car stopped well in the dry, and way better in the wet. I remember slamming on the brakes on the highway as a test after the dealership took care of the problem.

I tested it out in the wet as well and big improvement.

Fast forward a few months, and keep in mind no changes to any brake equipment, i now feel like i get the same sensation everytime i hit the brakes hard, but now all the time. Regardless of rain or dry.
to confirm running all stock equipment, and everytime i slam on the brakes at 80%-100% i get this wierd sensation of not having full stopping power.

Can anyone confirm what glazed rotors are.
Also, has this happened to anyone.

Last, will changing out to new oem rotors solve the problem?
I think i need them anyway, just making sure this is the issue.
Thanks in advance

 

Have you flushed your brake fluid? My dealer said it is recommended to flush annually. If there was any moisture or air in the system it will really diminish the braking capacity.

Roger

 

new stock pads rotors and stainless steel lines with Ate SUper blue and my brakes have been amazing. Try it youll like it.

-Suman

 

Glazed rotors will look very glassy, almost reflective. This occurs a lot of times when you change pad compounds, do not machine the rotors before installation, or do not break in the rotors properly. If you have cracks in the rotors and the mileage is pretty high, its time to change regardless of glazing.

When are you conducting these 80-100% stops? If you try something like that and you’ve been on the highway for along time, or the brakes are not up to temp it will feel like you aren’t getting any bite, and having to press the pedal really hard to get anything. If your testing full stopping power right after the dealer just refinished the rotors then you might have just undid their work. I don’t know what dealer you use, but I would figure out what their idea of deglazing means. Rotors need to be resurfaced on a lathe and also kept in spec. Maybe some one just hit them really quick with a grinder. Also if they deglaze the rotors they need to scuff the pads as well if they are not being replaced. After that you can very slowly wear in you brakes.

Maybe consider doing a little upgrade if you’re replacing parts. I’m sure you can find a good set of slotted Brembo’s in the OE size if you don’t necessarily want to do a full big brake kit. I have had very good luck with all slotted Brembo rotors. They are less prone to cracking then drilled, and the slots clean the pad, and help reduce gas buildup. I haven’t glazed any up either, even when I drive on them hard right away.

To prevent this from happening again, slowly break in your friction materials. There is a lot of info online about this, just google it. Keep in mind that with new rotors you need to let them gradually get used to heat, and give them plenty of time to cool off in between stops or else you will cause excessive run out and warp the new rotors.

It’s not that hard to do all this work yourself, and there’s a lot of info on 6speed. It would save you some cash too. After you get the new brakes, make sure you replace the brake fluid according to the manual (DOT 3 or 4), and flush it out. I have had Good luck with Brembo, and ATE products. I use ATE’s super blue racing fluid, which meets DOT 4 standards in all my cars. Its funny to see someone at the dealer pop open the reservoir cap and see it such a deep color.

 

By the time I typed up all of this some already beat me to it. I’m glad to see others using the super blue. Works really well. If you have the dealer power flush it through your system, you should have enough in one can to do it two times thoroughly. Stainless lines will help firm up the peddle under hard braking as well.

 

It means you are "limosine" stopping!
Stop that! (pun intended)
Be a man, and step on it!

Braking technique is the main cause (or bedding in) - but how to solve it -

If you rotors are glazed, you probably have glazed pads too.

For those of us that track, the cure is to us a set of aggressive/abrasive pad (Hawk Blue) and rough up the rotor with a abrasive pad to cut through a bit of the "scale". Then go out an really run hard with the brakes. Heat them up and bed them in properly (3 or 4 decel's from 80 to 30, then one or two really good ones from 100 to 50)

Now that you have the rotors scrubbed, go back to the stock pads. The roughened rebedded rotor will scrub the glazed pads.

You must re-bed ever time you switch either pad or rotor.

Also - never do new pads and new rotors - Do new rotors for a while on old pads, then upgrade pads.

 

I have very similar problem with my C2. I can get the ABS going, but the rate of deceleration is "just not there". I did flush the lines and put ATE Super Blue, as well as new Mintex Red Box, but I am getting the same sensation as I did with stock pads. Someone once told me that I should "scuff up" the rotors with some garnet sandpaper, but to be sure not to use any other type of sandpaper as the ferrous material could create havoc. Anyone else heard of this before?

 

Normally, on customer cars we leave the rotors on the lathe, and put a spin finish on them, I think it’s just a normal sand paper. Afterwards they get thoroughly sprayed with brake clean and blasted with shop air. I would not recommend high-speed bedding in to anyone. A gradual slow break in is best. People who have not done this procedure properly before will just overheat a new rotor and warp it. Messing around with aggressive race pads will just make the first couple stops on a cold morning suck. They will also eat your rotors up really fast. All euro cars eat rotors fast so a softer pad on the street is best. We will very rarely just pad slap a car. Also switching between pad compounds, new or old is a very big no no. I do more brake jobs in a week then most will ever do in their lives, we always put new pads on with new rotors, and always re cut old rotors that are still within spec if changing just pads. Good parts will most times have special material on the first slim layer to help the brakes mate up properly.

Get new brakes as you had planed, consider getting better rotors as I had said there are a lot of options out there. Make sure the fluid is flushed. It only can take so many heating cycles. I use blue because it seems to last longer. Then take it very easy on the brakes for the first week, no sudden stopping. On domestics a sudden stop, even only once can case the brakes to warp. Feel lucky your only dealing with glazing.

 

Sometimes making a couple of quick decelerations from 80 to 30 mph will take off the glaze.

 

Whew! so many things wrong with the above - where to start?

You always bed in new brakes. You have to establish a layer of pad material on the rotors to get them to stop. Whether stock pad or track, this *has* to be done or you will glaze all over again. You suggest that this can be done casually - I think you should be purposeful in this - Porsche's are sports cars - yes evey the piggish 996TT.

I was suggesting using an agressive pad material *as a cleaning procedure* - not to run with them for a few days or weeks. You need to cut through the glaze (and the "scale" just underneath) and then rebed with the appropriate pad that you normally run.

Carbide tooling or garnet paper are not going to get through this layer without removing significant rotor material.

Switching pads is fine - what a bunch of hooey. As long as you re-establish a bedding layer after removing the old pad bedded layer on the rotor you are fine.

Whew! what a bunch of misinformation around here. "Slim layer to help bed in brakes" whew!
No way. The only layer you need is a layer of pad material - deposited by properly bedding in.

Please refer to the experts if you doubt what I'm saying...

http://www.pagidusa.com/bedding_in_procedure.htm

and

http://www.braketechnology.com/techinfo.html#bedding

 

Apropos of nothing really but ATE Super Blue is the same as the oem fluid (ATE Type 200) it's just blue.

It makes for easy bleeds if you alternate between the two colors.

 

guys thanks alot for suggestions and ideas. some great ideas you guys have.
just for the purpose of understanding exactly what the car has been though, so we can figure out what the faulty item is:


here are a list of events that might have led to todays problem:
-took car for DE in homestead florida arond may. 2 days.

last day of DE, actually and luckily last lap, i boiled my brakes. (was running stock pads and stock fluids..i know i know..very bad, stock fluids)
bottom line, i lost my brakes for half an hour till things cooled off.

-a few days later i purchased motul fluid and bled everything myself.
*i have never bled brake fliud before, however i lurk the forums, ask my questions and get diy directions.
to my knowledge i did everything fine with the bleeding.

- around the same time i changed stock pads (which were worn) to mintex pads.
after the install was done, i tested the car out. In addition, to my knowledge, broke the pads in as recommended by other.

now that my pads and fluids were new, i finally decided to test the car out.
so i took it to the highway and did some threshold breaking.

-at the track a month before, i was amazed at the stopping power of the car. with the brakes properly warmed comin towards the turns, going 110mph, i suddently slammed on the brakes in order to take the turn at a reduced mph.
i was amazed how the brakes felt. the stopping power was amazing.
this was something my instructor was recommending to do. drive as fast as you can, and at a certain point before the turns brake as hard as you can till abs even kicks in.

-fast forward to after i installed the mintex pads and fluid flush and the breaks felt good... up untill i slammed on them.

ex. im driving for 15 minutes and next thing you know im flying... traffic appears to stop, and the only left between me and a bad accident is me slamming on the breaks with hope of me stopping.

while attempting to come to a complete stop, the car while braking, gives you this scary sensations that its not stopping like it can. feels like a grinding sensation between the pads and the rotors.


-fast forward a fwe months after i posted a few questions on the forums and concluded (at the time) that the mintex pads were the culprit.

i changed them back to new stock pads and the problem persisted as well. (especially in the rain, just like the mintex, however the more miles on brakes, the more it became pronounced on dry surfaces as well)

In ny i took the car to the dealership for an oilchange and asked them about the brakes.

The master tech who really knew his stuff took my car out for a few spins and came to the conclusion that they were glazed. he did tell me i might need new rotors soon, however they are within spec.

after "deglazing" the rotors, the problem was solved for a month or two.
everything was fine.

Recently i have been noticing the problem is back.
my question is this:

if i buy new rotors, should i buy new pads as well.
(rotors will be new, perhaps pads are glazed now that they were on old "glazed" rotors)
if the pads are in fact infected from the rotors, then it wouldnt be smart using them. (although they are pretty thick since they have been purchased a few months ago).

last, just to let people know status of rotors.
24k miles on car. (car had 10k when i purcahsed it).
i am under the impression that everyting was stock when i purchased the car cpo from long island/ny porsche dealership.
the pads were at 1/2-2/3rd of full capacity thickness and the rotors had very minimal cracks. You can barely see them (at 10k miles).
that to me was proof that everything with respect to brakes was same parts when the car was purchased new.

if i buy anything i would buy stock rotors again. i can get them for around 500 from sunsetimports.com. i dont think "buy a big brake kit" is an answer to why the above problem is persisting.

i would like to know the cause of the above problem. was it the mintex pads that messed everything up?

maybe its something i did wrong when installing. (although i dont think so).
maybe its because i just waited too long to change the stock rotors, which already have noticable cracks. (not from one drill to another, just small ones, but they are still there).
thanks for the help- much appreciated.

 

Stock brake fluid is the same as ATE Super Blue, as noted above.

The "stock" brake fluid should be just fine, especially for DEs.

Your fluid boiled because it was contaminated with moisture.

If your rotors are ready to be replaced I would start fresh with a set of new rotors and pads (if you're going to be mixing is some DEs grab some Pagids) installed by a professional (to eliminate your concerns about DIY contributing to your problems).

 

i actually agree. i wasnt planning on doin it myself this time around.
what pagids are good for 4-5 track days a year with 12k miles a year of daily driving. Noisy pads are definitely no good.

 

Bedding in new brakes, is something that does have to be done. With new rotors it should be done very lightly and not at high speed with a lot of cool down in between to start off with. It doesn’t matter what type of car, minivan or Ferrari, if you don’t know how to get pad transfer to the rotor surface properly, you will just end up causing squeaking, juddering, and excessive runout (warped). That’s why if you ask any dealer, mechanic, engineer they will say take it easy on the new parts until they get a few heat cycles on them.

Changing between pad compounds to get rid of glazing? This shows how much experience you have. If he was going to keep the brakes he has on, and just get rid of the glazing, all you have to do is re-bed the brakes. Casual driving on broken in brakes is what causes glazing. Normal street driving relies mainly on the abrasive properties of the brakes to stop the car thus un-beading the brakes by removing the pad material that was transferred to the rotor, via abrasion. I’m not saying you have to baby the brakes all the time, just until the new metal has been through enough heat cycles to have warping not be a issue.

He seems to rely on the dealer to do his work. If he wanted to change pads when getting new rotors, or to deglaze the brakes according to your technique they would change him twice the labor and laugh. No one does this. I was a tech for a good period of my life, never once has anyone asked me to reuse old pads to bed in new brakes, or install race pads to act as abrasive. I have however had people come back the next day and say they tested their brakes a few times and now they get a shudder. Telling a customer to go out and bed in new brakes, or to drive normally on them is inviting in trouble. Taking it easy will slowly introduce the pads and rotors to heat and still transfer pad material to the rotor face. Ask a shop how many times they have had people warp and ruin new rotors. That’s the most expensive part to replace as well, and with all euro cars you will replace rotors and not resurface them. This is a generalization, but most of them use softer rotor material as opposed to the majority of domestics using harder metal.


Using different compounds is probably what caused his original problem.

From Stoptech’s web site under their info section “white papers”

“Often times, weather or other conditions can prevent one from fully bedding-in the brakes before having to drive the car. Fortunately, this is not a dire situation. If you are running new street/performance pads and rotors, remember that they are designed for the street and will slowly bed-in by themselves over time. Typically just a few stops from moderate speeds will start the bed-in process for normal driving.”

“If you are changing pad compounds, such switching from street pads to track pads, you need to remove all of the material on the rotor and replace it with a fresh transfer layer of material from the new pads. To be honest, rotors do not like to have different compounds used on them, and virtually all rotor and pad manufacturers recommend that you do not swap pad compounds on the same rotors.”

Ask Brembo wilwood, MovIt, hawk, ATE or POSCHE, they will say the same thing.


Don’t harass me about this info, it is what ASE course, and tech schools will teach you. There are far to many experts on 6speed, but it’s easy to see which ones have actual experience.