Any tips on DIY Brake pad changes (for Carbons)?

[chrisn]

I bought an extra set of pads online (kit came with new mounting hardware and what I assume are wear sensors and some goop (anti squeak stuff?). I've got about three track days on the car and I'm not sure about longevity, so figured I would have an extra set on hard. I'm headed to Sonoma this weekend.I scoped things out a bit and it seems like a standard Brembo set up, but if anyone else has done it, I would love your tips-- especially on the proper use of sensors and goop.There is a decent chance that I am the first end-customer thinking about changing pads on a production NSX, so I realize that I might be on my own here [MENTION=33024]MasterNSXTech[/MENTION], I'm looking at you.

 

[docjohn]

what will be your endpoint for a pad change,,,do you have a minimum width for the pad ....does the the material flake off?

 

[chrisn]

I try to get my money's worth out of pads, but I also don't want to ruin those expensive rotors, So I will prob aim to change when material is about half the thickness of the backing plate. When the wear sensors trip, I will check on them after every session.

 

[docjohn]

Obviously with steel bbk's we run em down to near backing plate...and of course its easy to visually keep tabs on the rotors....I'm wondering where you are getting your benchmarks for these new carbon brakes? Have you gotten some parameters on wear from acura?

 

[chrisn]

Nope. Looks like they have sensor wires, so I assume that would be a conservative / early warning indication.

 

[docjohn]

where do the wires go? Do you think they monitor the distance between the pads? If so how does the computer know if the decrease in width is from pads or rotor? Or are there sensors built into the pad?

 

[Jinks]

Does the new nsx brakes give warning signs of overheating?

 

[docjohn]

yes....so maybe the wires are for temperature only not wear.....

 

[MasterNSXTech]

There is a decent chance that I am the first end-customer thinking about changing pads on a production NSX, so I realize that I might be on my own here @MasterNSXTech, I'm looking at you.

You're absolutely the first. If you thought those pads were a good chunck of cash, wait till the time comes to do rotors.

I would highly advise against changing the pads when they're down to only 50% left. After they're bedded in, pads and rotors have micro grooves that match to each other. Slapped by a new set of pads on would require an extra long break in procedure until the existing micro grooves on the rotors set in to the brand new flat pads.

Furthermore, when a dealer tech eventually does a brake service, there's a lot more that happens than simply just slapping a new set of pads in. There is a rather tedious cleaning process that happens with the rotors. Then they are weighed on a scale to determine if they are still good. Under street use, most likely the carbon rotors will last a ridiculous long time. Get some track days in there though and the rotors will get hot enough to burn off a little density. And if the density gets below a specific amount, then the rotor is considered no good anymore. Hence the scale. There is also a set amount of chips that are allowed in the material before the rotor is considered no good. And these rotors are especially fragile to impact damage...dealers were sent shields to cover the rotors to be used whenever the wheels come off for any reason.

 

[chrisn]

Thanks. Do you mean pads should be changed sooner or later than 50% of pad life left?

In other words: at what % or mm of pads should I change them? Porsche recommended only running them down to 1/3 of original thickness, for example (that was from my dealer-- perhaps not official Porsche guidance)

 

[MasterNSXTech]

Thanks. Do you mean pads should be changed sooner or later than 50% of pad life left?

In other words: at what % or mm of pads should I change them? Porsche recommended only running them down to 1/3 of original thickness, for example (that was from my dealer-- perhaps not official Porsche guidance)

Later. There is no "worn out" specification for the pads. But most shops either recommend replacement right when the little scraper bar touches (which is usually 2mm pad left) or 2mm from the scraper (which of course is 4mm pad left). Given the absurdly expensive nature of how much brake work is going to cost with the carbon units, I would not replace pads till they are at 2mm left, which translates to something like 20-30% remaining.

If you want to do them yourself, then like I said, be extremely careful not to bang anything against those rotors. But since you are tracking the car, there's a chance that the rotors may be below specification. So your brake service should be done at the dealer wheee they will do that long process of cleaning and weighing the rotors. It takes a few hours. So I highly doubt that most dealers' "free brake inspection" loss leader service is going to apply in your case.

 

[goldNSX]

So what is the price of one rotor?

 

[MasterNSXTech]

So what is the price of one rotor?

Rotors are sold as an axle set. We would only ever do one if it was a warranty replacement situation. The fronts are about $11k for the pair and the rears are something like $8300 for the pair.

 

[goldNSX]

The clutch is about 15k? Carbon too?
That's will be an expensive DD...

 

[MasterNSXTech]

The clutch is about 15k? Carbon too?
That's will be an expensive DD...

Clutch might be more. But minimum $15k I'd say.

Daily driven with little to no track days and the brakes will last an exceptionally long time. Don't go crazy with launch control, do the transmission fluids when you're supposed to, and the clutch will last a super long time. Maybe like fertile.

 

[geh]

Did a brake job on Sunday. Have to say I'm really disappointed in the carbon ceramic brakes for track use. At $900 a set the car got about 3 hard days on them before they were 60% done in front. After one more day with serious fading, the wear light came on. When the brake wear light comes on the pads are done RIGHT THEN!!! I discovered they wear the rears more than the front (which is bad because I only checked the fronts after two days, about the halfway point) and the rear pads wear REALLY UNEVENLY. Do not assume that because you see a lot of pad material through the calipers that is true everywhere. I have never seen pad wear this unevenly and I have been doing this a long time.

These are obviously Brembo brakes and the pads come out like all modern brakes, no trick there. The wear sensors are specific to each corner and not interchangeable or removable from the pads. Match up the part numbers of the existing and the replacement sensors before installing them. Once you have inserted the sensor into the pad, it will not come out. Releasing the sensor from its attachment to the car is a bit tricky till you figure out how it works. Look closely at your new sensors to see what is actually moving and use a small thin screwdriver. Otherwise, no big deal, although I would highly recommend getting some alignment studs for the wheels. You don't want to drop one on the ceramic rotors while trying to get the lug bolts installed.

I am going to start flipping my rear pads on the same wheel and rotate the fronts to the other side after two track days to see if I can get more life out of them. I will not be able to use the wear sensors when I do, but from the way the pads wore on the first set, that probably isn't a big deal. The difference between front wear side to side and at the rear just in the same pad is astonishing. If you track your car, keep a close eye on your pads.

Greg

 

[docjohn]

wow ...thanks for that...btw what track and tires you on?

 

[geh]

Thunderhill and Sonoma. Michelin Cup 2.

 

[docjohn]

since I'm a newb to the real world of carbon brakes how does your wear compare the Porsche and Ferrari guys?

 

[geh]

Unless the NSX Brakes are too small, I would suspect all ceramics wear about the same. Most people that track cars convert to iron rotors and save their pristine expensive ceramic rotors for resale time. To be honest, I have never used ceramic brakes on the track before this so I don't have a reference. Iron rotors with race pads have always worked just fine for me. In fact, even street pads work on the track, they just fade quicker. If you aren't tracking the car, I bet the ceramics will probably last forever.

Greg

 

[TDUDER]

Brake wear results from a test day

So, is the main reason for not using carbon ceramic brakes, the cost?

I find this very interesting... I never found a need for this but I had no choice when ordering in the beginning...

Also, You will find that you cannot "flip" the pads on one side, nor can you flip them from side to side. Good idea but Acura made sure you cannot do this...
I think the issue with brakes wear on the NSX is that there is minimal cooling, and the rear pads have abnormal wear: too much taper for the use.



Here is empirical data from a one day testing at Thunderhill's standard 3miile, CCW course.
(Partial Notes from this test day, copied from another post elsewhere. Total track time: 3 sessions, 25laps, 75miles, & a full tank of gas,)

This car is great to drive, but probably has marginal brake cooling for track use. The rear pads seem too small for track use.
I don’t think it’s quite a track ready car.
It was a very cool day with great track condition & the track surface was excellent. Should have made great HP.

I don’t think one could drive this car for 45 minutes.
I believe it would be into brake temp problems after 20 minutes, and then run out of gas.

With more track time & a better rhythm, I might be easier on the brakes. But, I would also be going faster all the time, which would end up being harder on the brakes, at the limit all the time…

In conclusion, it is a remarkably wonderful handling car, and it’s so much fun to drive.
It was fun to get to run it up to its limits.
I would do this again at a different track, just for the experience.
And, it would be fun to do this again with a good set of performance tires, but I would run only 5-6 lap sessions due to lack of brake cooling.
Disappointment: Could not hear the car at speed, but multiple reports that it really sounds fantastic on the track at speed… Just like all the comments on its looks… Amazing Machine….
Maintenance – Post Test Day maintenance & inspection:
Monitor Brakes pads
Before Track Day
OEM FRONT Brake pad thickness before Track Day: measured at 1500 mi. street use
LEFT FRONT Backing plate +pad (outside insulator not included)
LOT 15.36mm* LIT 15.41mm No Right side data
LOB 15.49mm LIB 15.39mm
Taper= 0.1 mm Taper= 0 mm
Rotor rotation is Bottom to Top

AFTER Track Day
OEM Front Brake pad thickness AFTER Track Day: measured at 1500 mi. street plus 75mi track…
LEFT FRONT Backing plate +pad (outside insulator not included)
LOT 14.91mm LIT 14.95mm No Right side data
LOB 14.80mm LIB 14.70mm
Taper= 0.11mm Taper= 0.25mm
Rotor rotation is Bottom to Top



Before Track Day
OEM REAR Brake pad thickness before Track Day: measured at 1500 mi. street use
LEFT REAR Backing plate +pad (outside insulator not included)
LOT 14.97mm* LIT 14.99mm No Right side data
LOB 14.95 LIB 15.02mm No Right side data
Taper= 0 mm Taper= 0 mm
Rotor Rotation is Top to Bottom

After Track Day
OEM Brake pad thickness before AFTER Track Day: measured at 1500 mi. street plus 75mi track…
LEFT REAR Backing plate +pad RIGHT REAR Backing plate +pad
LOT 14.15mm LIT 13.85mm RIT 14.02mm ROT 14.15mm
LOB 14.88mm LIB 14.40mm RIB 14.85mm ROB 14.75mm
Taper= 0.73mm Taper= 0.75 mm Taper= 0.83mm Taper= 0.60 mm
Rotor Rotation is Top to Bottom Rotor Rotation is Top to Bottom

My Conclusions:
I think 3/4 mm taper from 75miles, or 1hour of track testing is excessive.
You could work around this if you could “flip” the left and right sets, but the left rear pad set has a sensor cable that is 1.5” shorter (and different PN) than the right side.

BTW: The left outer rear pad sensor is broken and detached from the pad backing plate!
(I have tried to epoxy it into place. It should be replaced.)

When you consider that I have an expensive (not) optional Carbon Metallic brake system, on a car that is reportedly “ready to track test”, it is disappointing. The ONLY disappointing issue with this car.

My conclusion For Track Testing:
I think the fronts could use a more camber.
I think all the brakes need lots more cooling.
(Try this in the 100degree summer days & you would have to park it in 4 laps.)
Or, you could just slow down ;-)
I think a performance tire would make a big improvement, and the brakes would get even warmer…
I would never go out with less than ½ tank of gas (about 10 laps, 30 mi range)
I would like to turn off whatever rear traction control is being used in track mode, or have it explained in detail how it should be used…
Don’t do this too often because it is addictive…

No dings, no dents, no agricultural racing… near perfect day… too much fun.

T. Duder
Jan 2, 2017

(credit to ChrisN as I was able to discuss his testing & brake issues before I went to the track.)

 

[JLCoolman]

Very interesting information.

I wonder how the OEM iron brakes perform compared to the carbon ceramic brakes?