Brake pad grease carbonization with track use
 

Tracked the Z for four runs and had to "retire" after the clutch failed. The clutch failure could have been prevented if I had followed the forums advice and used RBF. But that is not the reason for this post. Upon removing the Carbotech brake pads all the pads, shims and anti-squeal had the brake pad grease completely carbonized. This occurred between the pad and shim and between the shim and the anti-squeal. Is this normal or did I use the wrong Nissan recommended high temp molly grease? Is there a preferred product?
On the four corners of each pad that ride on the caliper I used very high temp copper anti-sieze with no apparent issue, This is not recommened for the pad, shim and anti-squeal.

Another question is if pad grease should be used between the anit-squeal plate and the caliper pistons.

Carbonized pads and shims are VERY hard to clean......

After thought: Should the shim and anti-squeal be used on the track at all?

The only brake grease that I've used that can put up with most track use is Permatex Ceramic Extreme Brake Parts Lubricant: http://www.permatex.com/products/aut..._Lubricant.htm

http://www.permatex.com/images/Displ...4125.24124.jpg

I don't like using shims at the track as they add a slight bit of sponginess to brake pedal feel. Since we don't really care about brake squeal while tracking, there is no reason to have them there.

Respecting your knowledge you answered all my questions - +1.

Yeah, I suggest going commando. No grease and no shims.

However, you may find that adding brake cooling ducts with the grease Chris suggested may work.

I decided to leave the shims in place for the trackday I did in October. I used the Permatex grease as mentioned by Chris and it did didn't carbonize as the stock grease that was on there before, it only dried out a bit.. Track was Road America and I can assure the brakes did get hot!

I understand the shims might add a little sponginess to the pedal feel, but as I am not a pro racer, that didn't bother me too much. Reason I left the shims in place is I thought it might help to keep the heat away from the pistons a little better. Is this a completely bogus thought or might it help a little? (Chris_B, or other experienced track drivers)

What do the brake shims look like? I don't remember seeing them when I swapped out my pads for a track event.

It's those stainless steel, thin plates stuck to the back of the pads. About as big as the whole back plate of pad. You probably didn't notice them when you took the stock pads out because the shims are clamped to the pad and covered in old grease and brake dust.

Ah yep, I remember them. I left those on the stock pads. I just used some grease on the Carbotech's, all was good, except of course they were a bit noisy.

Noisy and dusty, my wheels were as dark gray as the car after one day at the track. But sure worth it at the track, so much better then the stock pads.

Haha, yeah. My wheels and parts of the bumper and quarter panels were like completely gray after just driving to the track. Yet alone after an entire day of track time. Ridiculously better than the stock pads.

Road America is pretty killer on brakes, right?!

Stainless steel shims do provide a small amount of heat insulation, but not much as they are thin. I've seen titanium used for the same reason. While Ti can be better (depending on which stainless steel alloy it is being compared to), a .020-.030" thick shim is just not thick enough to make a huge improvement.

Some professional racing pads, like the Mintex F3R, have been specifically developed to reduce heat transfer. The current version is a 35% improvement over the early compound. Shims are in typically the 2-4% range, which pales in comparison.

Thanks for the detailed feedback Chris! Good to know my thinking wasn't completely off. But yeah, a 2 to 4% reduction in heat transfer is negligible in rotor temperatures of what? 500 to 800 degrees?? So next time I'll just leave them of when I go to the track.

Yep, RA is hard on brakes, even though I was taking it easy as it was my first track day with the Z. Sure glad I upgraded Pads and fluid before I went there.