[Note: I posted this in the Brakes/Suspension forum with little response.]

Three month ago, I changed out my OEM brake pads for some Endless SuperStreet Sport-S pads. After changing them, I bedded them in (twice actually) and have had no problems with them since that time. They stopped great - I even ran them on a HPDE with no problems at all.

Yesterday morning on the way to work, somebody pulled over in my lane forcing me to brake hard. To my shock, I almost couldn't stop the car.

This afternoon I was on an isolated highway and decided to test my brakes and sure enough, it was like they had no stopping power. I repeated three 70 mph to 20 mph hard braking stops to heat them up and they seemed to get their grip back.

Those Endless pads are streetable, so they shouldn't and haven't required a warmup. I'm wondering if it's just some kind of buildup on the rotors or on the pad face. I haven't been braking hard very much on the street and the last couple of autocrosses have been in the rain so no hard braking there either. The fact that the grip came back after a couple hard stops leads me to think it's either heating them up or it cleaned the surface of the pads/rotors.


Any ideas of what might be going on or what I can check or test?

 

Some pads deposit a lot of material on the rotor surface.
Might try bead blasting the rotors clean/scotch-brite the pads. Go back thru the bed in procedure. See how that works for you.

We always use to do this when ever we changed pads on the race cars/bikes. Ensured the differnet pad compounds did not affect each other adversily.

 

The strange thing is that they worked great after swapping the pads out. Now, after a couple months of regular driving on them I seeing the problem.

One thing that I did notice, in the first month or so after the swapout, they seemed to be dustier than they are now. I remember thinking to myself that they were supposed to be a lot less dustier than the stock pads but they didn't start out that way.

I may pull them off this weekend and try lightly sanding down the rotors to make sure they're clean then go through the bedding again.

 

The daily driving does not get the pads up to their optimal operating temperature. The pads are more likely to place deposits on the rotors when they are cold. When the pads get up to temp they are kind of 'self cleaning'.

Do not use sandpaper on the rotors. Way to aggressive, you will take metal off as well as a the deposited brake material. Take them to a local machine shop or bribe someone w/ a media blasting cabinet. Try to use a media that is not silicon based. Although, beggers can't be choosers.

 

WTF ?!?!

Pad material deposit IS what you want in order to have decent brake performance. Don’t try to sand your rotors unless you’re having some brake judder issues.

Your pads were dustier when new because they were setting themselves and conforming to the uneven rotors surface. During that time, you’re not braking on 100% of the brake surface. This, IMO, is the way to go. Dealers will cut your rotors to speed up this process. They actually speed up the time it will take for them to sell you new rotors…

Now, these pads are “Street sport” pads so they will require some heat in them in order to work properly. Driving 20 minutes on the highway is the best way to cool your rotors down. Plenty of air and limited friction. Also, driving around and never really warming the brakes will have them run in abrasive mode (versus adhesive mode when warm and they contact deposited pads material on the rotor – this is the good way to go) so you’re basically sanding your rotors clean every day. A clean rotor does not help in generating brake torque.

Proof of that is your comment of the brakes finally coming together after a couple of hard braking. This is actually a bed-in technique, depositing a fresh layer of pad material on your rotors. Once they have cooled completely, you’ll have your good brakes back.

Moral of the story, if you get “sport pads” your better do some “sport driving”.

 

So what you're saying is that by NOT braking them hard regularly, I'm actually doing more harm than good. Because of all the rain lately, I definitely haven't been braking hard. Well, I guess it's back to "coming in hot and braking hard". Thanks

 

As stated above, brake pads grip best when they are gripping a rotor that has a thin layer of the same pad material evenly distributed across the rotor surface. Rain and light braking are very effective in removing this layer from the rotors.

I've normally 600 grit Garnet sandpaper to clean rotor surfaces when changing to a different pad material. I've also used it to clean up and fix a "warped" rotor.

 

More proof that 'do it all' pads do nothing well. What you're describing seems to be dangerous on the street when cold. I'd bet they would fade at high temps seen at the track too.
Do you know how much pad material you have left? I've felt that my braking characteristics sometimes change as my pads wear down.

 

i have my own thread going on, looking for pads myself, and these are the very conditions that I am looking to avoid.

Someone made the comment about "do it all pads" and I suppose you're right to some degree, although I don't know that these particular pads are supposedly "do it all".

I'm current running pagid pads, and they by no means are "do it all" however they NEVER did anything like this, even when they were cold, or TOO much build-up.

My main complaint about them is the noise, when they are under street conditions until they warm up...

But that I can handle..

Not stopping??!?!??!??!?!??!?!?!?

 

It might sound weird, but yes, you got it right!

I like the OEM pads for the street. Not the best torque, but it's always there and consistant.

I switch to dedicated track pads for my HPDE events.

 

They're only a few months old with barely 2-3K miles on them. I have looked but I'd suspect they still have a LOT of pad left.

 

I just wanted to back you on this.

Specially in my case, where I have brembos, the oem pads really do a great job, but obviously as the heat and immediate wear-n-tear adds up in a track condition, or if you are "pushing" them/your car, that is where a performance pad takes up the slack!

 

UPDATE: I have finally discovered what is causing this problem - water. On a couple more occasions the same thing happened again, I went to use the brakes and noticed that they were not up to their normal stopping power. I finally realized, each time it occurred after a hard rain or I washed my wheels a certain way.

For example, this morning it was raining real hard. I had to drive through a lot of standing water to get to work. Especially the last mile where I didn't have to use the brakes much.

This afternoon when I get ready to leave work, just at the car starts to move, I hear the loud clunk of the brake pads popping loose from the rotors. I get out on the road and the first time I try to stop from 45mph, the brakes are not working much at all.

Several times in the past, if I wash my Z and let it sit overnight, the next morning the pads will be stuck to the rotors. Their braking ability will suck for a while then eventually get back to normal. If I drive the car immediately after washing, the problem doesn't occur. I guess that drys the pads/rotors and prevents any buildup of dust & rust.

My guess is that the metal in the pads is rusting on the fresh exposed surface and reducing the grip. Once I scuff it off, things get back to normal.

 

I would check a few things before you say it's rain:

- Bleed the brakes again, you may have boiled some of the fluid at your track day.
- Check the operating temperature of your pads, you may need to warm them up for them to work.

 

I have bled them several times recently as a result of HPDEs. In fact, I bled them last Saturday. Pedal firmness hasn't been a problem, it's definitely "grip".

Endless claims that the operating temperature for these pads is 32ºF - 932ºF. While I'm not at the bottom end of that range, I'm sure a little heating helps.

One thing that I did notice in their literature is that "the pads are ceramic plus other compounds and contains no steel". So it's not really rust forming unless it coming from the rotors.

I'm not really saying it's rain as much as it's soaking of the pads and rotors and letting them "air dry". I regularly drive in the rain and have no problems with them later. What different is that the rotors and pads are hot so they dry quickly under normal circumstances.

 

Failing Master Cylinder or Booster could cause the brakes to seem to be working poorly. I would check both and make sure they are operating properly before blameing the pads compleately.

 

FWIW...When I don't drive my Z for a week or two and it rains or is very humid the rotors will develop a very fine surface rust that, I assume, removes any deposited pad material. If I don't re-bed the brakes when I first drive it my braking ability is definitely reduced. I'm not sure how long you let your car sit, but the washing issues you describe sound like they have the same results as me letting my car sit. BTW I run Carbotech Panther+ pads.

 

Oh, I can definitely see the rust bloom on the rotors after I've washed the Z and it sits overnight.

 

If rain is your big issue, you may want to consider a slotted or drilled rotor. Water evacuation is one of their key benefits. We don't recommend drilled if you are going to track the car. If you're only going to be driving on the street, and water is your main problem, then drilled would be the best choice. The idea is that they will give your pads more leading edges to bite into.