I'm looking for some input from the more mechanically inclined members here. I recently had new oem brembos and project mu pads installed on the front. I bedded them in and everything felt good initially. Recently though I've noticed that under hard braking I'm feeling and hearing what I would describe as scraping/grinding.

The first time it happened I had to do a very hard stop and I heard and felt the grinding, but I assumed that maybe the wheels slipped some and it was just the ABS that kicked in. Since that incident it's happened a couple of other times under what I would consider hard but normal braking and I'm pretty sure it's not the ABS. It's almost as if when the brakes are fully depressed there is metal on metal contact somewhere. Anyone have any ideas what could be causing this?

 

Take out the pads and examine them and the rotors. Check for unusual wear. Make sure nothing is loose. Also make sure the brake surface areas are clear of debris.

 

My brakes do this all the time and after several different sets. I was at first concerned until I examined my brakes, I see no issue visually. Car stops on a dime, all good. One thing I will say is I'm sure that grinding always starts after bedding the brakes in. At first there in no noise, then after bed in, they make that grind you're talking about. 5 sets of brakes I've had on my car and they all have eventually made that noise. I wonder if our brakes were totally smooth (without the drill holes) if that noise would still be there.

 

I agree with pulling the pads to examine them if possible. I can't think of anything that would cause metal on metal contact but if it did exist it should be pretty obvious after pulling the pads and looking at everything.

You mentioned the noise and feeling occurring at higher pedal pressures but I'm curious if the volume and/or pitch of the noise is also speed dependent. What is the feeling you are experiencing? Is it more of a vibration or just a steady metallic grinding sensation?

-Matt M.

 

I also experience this but havent had a chance to inspect the pads....but like "compthis" said, car still stops.

 

I find it most obvious when I'm driving down my ramp to the garage moving slowly with brakes applied the way down.

 

I would say it's definitely speed dependent, and it seems to happen mainly when I'm braking at the bottom of a hill. It's only happened a handful of times, I don't hear the grinding every time I apply the brakes. Also, I do intermittently feel some slight vibration during medium pedal pressure, but the grinding only happens during pretty much full pressure. The grinding feel is more of a pulsating feeling rather than steady grinding.

Just from looking through the wheels the rotors appear to have normal wear. I did notice that the pads had a good amount of debris around the edges. Is this normal for project mu? Most of the debris is gray but some of it had kind of a brownish color too.

 

Do you mind taking some photos of the rotors and pads for me? I would like to get a better idea of what you mean by debris if possible.

-Matt M.

 

I have this after ALL track days. Look at the holes in the rotors. If they are clogged it will do that. Must be braking hard to get that .

 

I have the same setup (brembo rotors with Project Mu pads). After I wash my car I have this exact issue. It feels like a combination of ABS and grinding. For me it only occurs when the brakes are wet and when coming to a complete stop, around 5-10MPH to 0. After a bit of driving the brakes dry out and the issue goes away.

Is your issue related to moisture, either from rain or car wash?

 

I am assuming you have drilled rotors? Some pads tend to be more gritty than others. When that grit fills the drilled holes you can start to feel it, particularly at lower speeds.

Were going to stock some Endless MX72 pads for the ISF, but had exactly the same problem you describe (the other problem was the ridiculous price:-). When we power washed the rotors to clean out the holes the problem went away for a while, but returned after any hard braking session.

-Rafi

 

I think you may be right. I washed the car the other day and this time I didn't see any debris around the pad edges as I've seen before, but I did notice that the holes in rotors had some grit in them. I drive fairly agressively but don't think anything out of the ordinary. Seems like it's normal and just something ill have to get used to.

 

Next time you wash the car, just spray some brake or wheel cleaner on the rotors and rinse with high pressure spray, that will clean out all the grit that accumulates.

 

I use a 5/32 drill bit on my screw gun to clear the holes after a track weekend. It's slow, but it gets the pad dust and the new layer of corrosion at the same time.