Nave43

Ive searched around the internet and cant really find a solid answer. If someone does have an answer, they never have any proof to back it up. Just a "yeah you can do that" or "No just dont"... So i figured i would ask here on Honda-tech were i know there is a knowledgeable user base who usually demand proof before jumping on a band wagon.

Not that it matters for this thread but rules are rules.
I drive a 93 Del Sol Si
D16A motor swap
209k on the body
150K on the motor
Wagner Thermo Quiet Ceramic brake pads installed about 4,000 miles ago
I just cleaned and re-greased all the slider pins as preventative maintenance.

Now for my question can i install new rotors with my old pads? If so why? Or why not? I am only replacing the front rotors, and dont seam to have any uneven pad wear up there. Though the pads are "grooved" from how bad the old rotors were. Any info would be greatly appreciated.

B serious

iTrader: (1)

If the pads are grooved, I would just buy new pads.

You CAN use them with new rotors. You'd need to bed them in as if you were doing a new set of brakes....no big deal.

Pads for that car are probably like $10-20 for decent ones at rockauto.com. For that money, I'd just buy new pads. Buy something that's not going to glaze or leave deposits.

Nave43

I was planning on bedding them in but thank you for the heads up. Are the "Wagner thermo quiet ceramic" pads i have on now up to par with what you said about not leaving deposits and such? If i were to use the existing pads what would be the downside? Ide prefer not to replace them being as they are so new and i have other things on the vehicle that need fixed. Ive also read from some unreliable sources that using old pads is actually better for bedding in new rotors. Is there any science behind this?

EnjoyTheRideDC2

iTrader: (1)

You can run new rotors without changing brake pads, but its not usually recommended. The brake pad surface has been shaped from the previous set of rotors. Whatever characteristics your old rotor surface had are now bedded into the pad. They wont mate perfectly with the smooth surface of a new rotor. Your car will still stop when you apply your brakes, but it might be noisy or the pads may produce more dust as they wear down.

Glazed pads are a result of overheating your pads beyond their operating temperature. You can glaze any brake pad if you push them beyond their specified limits. As long as this isn't your track car, you wont experience glazing with most decent replacement pads.

Nave43

What if in theory i sanded the old pads smooth?

MAD_MIKE

You can reuse old pads with new rotors, just properly bedding them in is all that is needed to be done.
I usually do about 10 consecutive slow downs from 60-10MPH twice, similar to when slowing down at a medium>short off ramp. Don't stop, don't get into ABS, don't lock the wheels while bedding in the pads. I usually go out when there is little to no traffic on the freeway, find a nice straight stretch and proceed. Don't drag the pads, slow down like you are slowing down from 60-10 with intent. If you begin to smell brakes you may be over doing it a bit, you want them hot but not cooking hot, if the pedal starts to get soft you are definitely getting the brakes too hot.

You will need the pads/rotors hot enough to transfer brake material and machine the interface between pad and rotor for maximum coverage/grip.
After you have done the heating and bedding, drive around without stopping for another 15-20mins to ensure the pads and rotors have cooled down.
If you stop immediately after the bedding in, there will be a spot on the rotor where the caliper is that will have excessive materiel baked onto the rotor creating a high spot which will require rebedding the pads to wipe away the high spot, or worse cause a hard spot(cementite) if this happens the rotor cannot be machined to fix the hard spot and will need to be replaced.

Since the pads are already seasoned, you may only need to do 10 slow downs rather than 20.

Sanding the pads is not necessary. If there was a groove in the old rotors from the pad, there may have been foreign material stuck between rotor and pad. If the rotors were merely just wavy, that is normal. If there is a hard spot on the pad, removal of the ridge may not prevent the groove again if that part of the pad has a hard spot. Grooving may occur again.
If you feel the need to mill the pads flat, call the tech line for your brand of pads. Certain sand papers contain metals that may affect the bedding in and friction coefficient of the pads.

Nave43

Thank you for explaining glazing, This vehicle is just for road-trips and occasional spirited driving so from what you said it shouldn't be an issue. Although i live in Pennsylvania and its VERY mountainous so the brakes do get a lot of use and can get rather hot at times.

Its the pads that are grooved from the old rotor being so worn, not the other way around. Im pretty sure there is no foreign materials causing the ware due to the fact i recently inspected the pads and rotors and there were no debris or anything of that sort, and the pads are worn the same on both sides. Im afraid the grooved pad will cause hot spots in the rotor while bedding which may affect it for the rest of its lifetime. Which is why i had the idea of sanding it. Though thank you for the proper bedding procedure, it saves me a search Would the bedding procedure wear the pads enough to be flush with the new smooth rotors?

I will check the old pads i removed last time i did brakes to see if the grooving occurred on those as-well or if its new to these pads. If it is new to these pads there maybe a problem there.


P.S.
I dont have abs so that is not an issue.
I live in the middle of nowhere so finding a road to do this on will be no problem.
I didn't think of the sandpaper affecting the pad, good looking out

B serious

iTrader: (1)

You can glaze shitty parts store pads at normal speeds.

The pads you currently have should be fine...except they're grooved. It's going to transfer that wear pattern into your new rotor.

I'd just start fresh with good pads and new rotors. Again...all this stuff is cheap at rockauto

Nave43

So my fears have been, confirmed. I am going to get new pads before installing the new rotors. 28$ seems like a worthy investment in the long run.

While im now confident that sanding it would work, with how deep the grooves are i dont think its worth the effort.

At this point i am more interested in the science of it for future reference. So i can pass the info onto friends and others that need help, or anyone who reads this thread in the future. With that in mind is there any proof behind the people saying that its better to bed new rotors with old pads? (If they weren't grooved of coarse)

B serious

iTrader: (1)

I think the reasoning is that old pads already have a good "working" surface that should be smoothed out and be working properly. Se brand new pads don't come prepped for instant break in. So you have to break the pads in...as well as the rotors. You have to get through the useless layer of glue or whatever else is on the surface to start breaking in the pad.

Again....I usually recommend not buying parts store "house" brand pads. I once bought autozone's best $40 ceramic pad set for my EM1 and hated them. I have similar experiences with advance auto pads.

For less than those prices, I could buy something nice from rockauto like powerstop or akebono or centric.

Nave43

Thank you for the info. I now feel like a have a firm intellectual hold on the situation at hand. Enough so to make an educated decision anyway. I personally would never buy the "wearever" or other parts store brand pads. To me brakes are one place you NEVER want to skimp on.

Slightly unrelated but do you use ceramic or Semi metallic pads? I have been using these Wagner ceramics and they are quality, quiet, and produce almost no dust, BUT i dont feel as if they grab like the semi metallics i had on the car before. Im not sure what brand they were they were installed by the previous owner. Hence why i changed them as soon as i got the car home even though they had plenty of life left.

B serious

iTrader: (1)

I like to put pads in 4 categories (with examples):

-general use (factory pads, parts store pads)
-sport (Powerstop Z16, Hawk HPS)
-intermediate (Hawk HP+, Stoptech SP)
-track/race (Carbotech XP10/12/16, Hawk DTC, Cobalt XR1)

Generally speaking...within any of those categories, semi metallics are going to be more bitey/agressive than ceramics in the same category.

Performance oriented ceramics feel nice. The general use ones do not. For example, the factory semi metallic Honda pads on my girlfriend's AP2 S2000 felt much better than my AP1's factory ceramics.

If I had to buy general use pads, I would probably go for semi-metallics.

One problem with semi metallic pads, however, is the dust that can potentially be corrosive...and there's usually more of it than the comparable ceramic pad. I don't mind dusty wheels. I do mind when the dust etches itself into the wheels and they can't be cleaned anymore.

I like the feel of agressive pads. But I like the non-corrosive dust and linear feel of ceramics.

My solution is to buy a non-semi metallic pad....but in a more agressive category than you'd usually use on the street. I usually use something on the "sport" or "intermediate" side for the street.

One of my favorite street pads has been the stoptech street performance (made from an aramid material). Good bite, nice linear climb, no corrosive dust (there is quite a bit of dust...but it washes off easily).

On the milder side, Powerstop Z16's are pretty nice. I believe they are a performance ceramic compound...which I thought felt similar to Akebono performance ceramics. The Akebono was probably a slightly better pad, however.

I just put powerstop Z23 carbon ceramics on my TSX, accompanied by a factory big brake kit and I'm really liking those pads as well. Similar to the Stoptech, but with slightly more bite.

I don't know what my factory DC2 ITR pads were made from...but I liked those as well.

I use Carbotech (ceramic-metallic) on the race track. I have used straight semi-metallics on the track as well (Hawk), but I don't like how bitey semi-metallic track/intermediate pads are.

Nave43

/\ Thank you that was exactly what i was looking for . You have been a giant help, as always.

PSI GUY

iTrader: (2)

I install new rotors from time to time, being under warranty or a replacement without new pads. I have a pack of 80 grit sandpaper in my cabinet that i put on the bench and just rub the pad on it till all the grooves are gone, clean them up with some brake clean and a good roadtest and bed them in and you are good to go. Depending on the pad compound it may take a few seconds or a couple of minutes to get the grooves out.

Nave43

Semi metallic or ceramic? Have you had any negative impacts from using the sand paper on the pads? Such as particles from the sandpaper embedded in the pad?

EnjoyTheRideDC2

iTrader: (1)

The brake cleaner washes away the loose foreign matter on the pad surface. Besides, sandpaper particles wont embed themselves into the pad due to the lack of heat.

IMO, the negative impacts of running old pads on new rotors would go unnoticed to most drivers. I doubt most can recall exactly how their braking performance was before and after the change of said components. The car is going to stop when you apply your brake pedal...

Ceramic pads were designed to produce minimal dust and be noise free...that's it. There isn't really a "performance" ceramic pad. A quality semi metallic pad will always outperform a ceramic pad in terms of braking ability.

With Semi Metallic pads: If dust is the problem, give your wheels a deep cleaning and dress it with Armor All wheel protectant afterwards. Whatever light traces of dust the wheel accumulates will be easily washed off the next time you wash your car. If noise is the problem, try not to ride your brakes too much and give your brakes a quick scrub once in a while as you're exiting the freeway.