According to Danoland, you should replace brake pads when 1.7 mm (1/3 the thickness of the backing plate) of pad material is left. My outer pads are about the thickness of the backing plate (approx. 5 mm). My problem lies in the inspection of the inner pads on both the front and rear wheels; with the wheels removed, the caliper bracket obstructs all but about 2 mm of the inner pads thickness. Do I assume, the inner pads are wearing the same as the outer, or do I need to remove the caliper and inner pads for inspection? Also, I have 70,000 miles on the pads, and I am trying to estimate the remaining miles before servicing; assuming identical driving conditions. What is the thickness of new OEM pads? For example, if new pads are 9 mm, and I have 5 mm left, and should service at 1.7 mm, then each mm is good for 17,500 miles, and if I don’t need to service for another 3mm, then I don’t need brakes until another 50,000 miles … right?
Inner Brake Pad Inspection
- Thread starter Slingshot
- Start date
I believe that OEM brake pads come new with 8.8mm of pad material…not 100% sure though. It has been my experience that the front pads wear evenly and the rear inside pads wear about 10% faster than the rear outside pads. Man, you’re easy on your brakes!!
DanO
DanO
Thanks DanO ... and thanks for the best DIY website on the globe! Not many stop lites in my part of the woods ... just space ships
[This message has been edited by Slingshot (edited 01 March 2003).]
[This message has been edited by Slingshot (edited 01 March 2003).]
I believe the front OEM pads come with 11 mm of pad material and the rear ones with 9 mm.
Let me look it up in the service manual to double-check, hold on a sec...
I was very close. The service manual says that it's 11 mm in front, but 9.5 mm in the rear.
The service manual also says that the service limit (the minimum thickness at which to change them) is 1.6 mm. That's fine if you're watching them closely but if they're OEM pads, you'll probably find that they start to squeal (when the metal tab comes into contact with the rotor) when they're around 2.0 mm thick or so, I am guessing, and you'll change them at that point just to shut them up.
You said you have 70,000 miles on them but you didn't say whether the ones with 5 mm left are the front pads or the rear pads. If you're down to 5 mm in front, then assuming the same rate of usage, you will get another 35,000 miles on them when they're down to 2 mm. If you're down to 5 mm in the rear, then you will get another 46,667 miles on them when they're down to 2 mm.
Let me look it up in the service manual to double-check, hold on a sec...
I was very close. The service manual says that it's 11 mm in front, but 9.5 mm in the rear.
The service manual also says that the service limit (the minimum thickness at which to change them) is 1.6 mm. That's fine if you're watching them closely but if they're OEM pads, you'll probably find that they start to squeal (when the metal tab comes into contact with the rotor) when they're around 2.0 mm thick or so, I am guessing, and you'll change them at that point just to shut them up.
You said you have 70,000 miles on them but you didn't say whether the ones with 5 mm left are the front pads or the rear pads. If you're down to 5 mm in front, then assuming the same rate of usage, you will get another 35,000 miles on them when they're down to 2 mm. If you're down to 5 mm in the rear, then you will get another 46,667 miles on them when they're down to 2 mm.
I just located this on an old thread...
For the NSX:
FRONT OEM PAD
PAD NUMBER: D503
TOTAL THICKNESS: 0.681" / 17.3mm
PAD MATERIAL THICKNESS: 0.425" / 10.8mm
REAR OEM PAD
PAD NUMBER: D504
TOTAL THICKNESS: 0.595" / 15.1mm
PAD MATERIAL THICKNESS: 0.359" / 9.1mm
Both front and rear have approximately 5 mm left, and being an estimator, I like to keep numbers heavily rounded ... like 50,000
Based on Dan's comment of 10% faster wear on the inner pad, I will use 4mm on the rear less 2mm service interval, and will probably replace in another 30,000 miles to play it safe. That should be in another 10 years the rate I am piling up the miles
For the NSX:
FRONT OEM PAD
PAD NUMBER: D503
TOTAL THICKNESS: 0.681" / 17.3mm
PAD MATERIAL THICKNESS: 0.425" / 10.8mm
REAR OEM PAD
PAD NUMBER: D504
TOTAL THICKNESS: 0.595" / 15.1mm
PAD MATERIAL THICKNESS: 0.359" / 9.1mm
Both front and rear have approximately 5 mm left, and being an estimator, I like to keep numbers heavily rounded ... like 50,000
Can pads be assumed to wear at a linear rate, or does the wear-rate increase with degradation of the rotor surfaces?
Richard
Richard
Ken and Slingshot, thanks for the correction on the OEM brake pad thickness, I'll update the danoland DIY pages with these numbers.
That’s a good question! I’d say that with typical street driving, one can assume linear wear. With extreme temperature conditions, like at the track, it’s probably quite a bit less linear.
DanO
You should remove the caliper and inspect the pads visually. It is my experience that the inner pad wears more quickly on the rear brakes and also that pad wear increases toward the end. Check to make sure yours are OK.
[This message has been edited by Soichiro (edited 02 March 2003).]
[This message has been edited by Soichiro (edited 02 March 2003).]
Where does this information come from and why is it different from that specified in the service manual?
The piston-side (inner) pad wears faster than the outer pad. You should be able to inspect the inner pad with out removal of the caliper at the point on the pad which is closest to the hub. Sounds like you're about at the time where you want to have some pads on hand.
If the piston side wears faster than the outter pad, you have a problem. Most likely because of the sliders are bad, or not enough grease, or you didn't grease it when you replace your pads.
If you take care of the sliders, the difference in wear on the outter and inner pads should be negligible.
If you take care of the sliders, the difference in wear on the outter and inner pads should be negligible.
Not from what I have seen on many NSXes. The inner pad is pressed against the disc before the outer, and for a longer period as the piston retracts. The wear difference is not significant, but is different.
Regards,
-- Chris
Regards,
-- Chris
It sounds like the thicknesses of 10.8 mm and 9.1 mm might actually be for the aftermarket brake pads sold by HomeDepotNSX's former employer, whereas the OEM pads would meet the specs in the service manual of 11.0 mm and 9.5 mm.
[This message has been edited by nsxtasy (edited 03 March 2003).]
Chris,
I am not disagree-ing with you. But the floating caliper design assure the inner and outter pads get the same equal force assuming the slider is functioning properly. It is a simple physics. The piston do not retract. It was discovered a long time ago, that the pads will drag slightly but it wil cause no ill effect. This is also mentioned in a couple of automotive engineering book like Carrol Smith's book.
What I'm trying to say is there will be a wear difference, but it is very insignificant that you should not be concern about. If the difference is significant enough, and cause concern, there is a problem with the caliper or slider.
I am not disagree-ing with you. But the floating caliper design assure the inner and outter pads get the same equal force assuming the slider is functioning properly. It is a simple physics. The piston do not retract. It was discovered a long time ago, that the pads will drag slightly but it wil cause no ill effect. This is also mentioned in a couple of automotive engineering book like Carrol Smith's book.
What I'm trying to say is there will be a wear difference, but it is very insignificant that you should not be concern about. If the difference is significant enough, and cause concern, there is a problem with the caliper or slider.
I think you read my mind Chris. I think I will replace them just in case I decide to track the car some day. At least I won't look like a rookie changing pads, and if I don't track the car, and continue with the current useage, I will never have to worry about it again. I feel like a Maytag repairman. I want to tinker with the car, and nothing really has broken
Do you recommend your Carbotech Panther Plus even if I am 100% street use, or will my rotors wearout prematurely?
[This message has been edited by Slingshot (edited 03 March 2003).]
[This message has been edited by Slingshot (edited 03 March 2003).]
He is no longer with Carbotech.
In my experience, I have yet to hear of anything short of pure race pads that actually wears out rotors. If you're tracking your car, your rotors will probably develop hot spots (shudder) or cracks long before they wear out, and if you're not tracking your car, your rotors will probably never wear out.
