Sand rotors when changing pad compound?

A forum for the legendary Nissan Pathfinder and Infiniti QX4.
A1218
Posts: 308
Joined: Thu Aug 06, 2020 6:03 pm
Car: 1997 Nissan Pathfinder SE

Post

I’m changing the pads on my 97 Pathfinder from Akebono Ceramics to Hawk Fierro Carbon LTS pads as I want something with more bite. I’m not too happy with the Akebono on this vehicle, especially when the pads are not hot after cruising for a while on the highway or when it’s cold, the bite is not too great. I have drilled and slotted rotors on the vehicle.

Is it necessary to sand the rotors lightly when changing compounds? I believe the instruction said to do so but I just want to make sure and avoid damaging the rotors.


User avatar
mdmellott
Posts: 1147
Joined: Mon Sep 02, 2019 3:32 pm
Car: '13 Kia Soul+ 2.0L AT
'02 Pathfinder SE 3.5L AT P/4WD
Location: SF Bay Area, CA

Post

Used rotors, even in good condition, will often have a polished, glazed surface created by the old pads and the old pads will often leave a very small, sometimes sharp, lip protruding at the outer surface edges of the rotor where the old pads do not make contact with the rotor. I always dress old rotors to remove the glazed finish and if there is a lip, I will carefully remove that with a fine file. For rotors in very good condition, I usually use a fine grit emery cloth sand paper and oil to removed the glazed finish. For rotors that are not so perfectly flat but still in fair condition, like the last time I replaced my pads 6mo ago, I use the fine grit side of a small sharpening stone to flatten out the high spots and remove the glaze at the same time. The stone will also remove and flatten out the outer lip as well but you may still need to hit it with a file first if the lip is too big. Since you have slotted and drilled rotors, I recommend using a block to keep sand paper flat onto the surface of the rotor as you dress it up, otherwise you may round off the edges of the slots and holes if you just hold the sand paper in hand causing your finger tips to press into those edges. The fine grit side of a sharpening stone will work well for this also. The size of the stone I bought was only 3" x 1.5" so it was easy to dress the rotors' entire surface areas very quickly.
Attachments
Sharpening Stone.JPG

User avatar
VStar650CL
Technical Expert
Posts: 8294
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Post

Switching from ceramics to organic/metallic or vice versa always requires a light cut. Ceramics need a microscopically-rough initial surface to heat up and bed properly, and then they leave a thin layer of ceramic material embedded in the rotor surface. That layer is incompatible with organic/metallic. So switching in either direction requires a cut.

A1218
Posts: 308
Joined: Thu Aug 06, 2020 6:03 pm
Car: 1997 Nissan Pathfinder SE

Post

So would the light sand in the methods Md recommended above be appropriate for my case? The drilled and slotted rotors I have on are close to 2 years old and in great condition. When you say cut, do you mean machine cut or the sand method?

User avatar
VStar650CL
Technical Expert
Posts: 8294
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Post

No, you need to cut. Sanding would probably suffice if switching to ceramic, but not from. The embedded ceramic layer needs to be completely removed.

User avatar
VStar650CL
Technical Expert
Posts: 8294
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Post

PS - BTW, if you have them cut at a parts store and not a machine shop, pay them extra to do the lathe passes at the slowest travel speed and a maximum 0.002" per pass. Drill-and-Slot rotors are pretty intolerant of the usual 0.005" one-pass treatment. Professional machinists will usually know better, but the parts guy may not.

Mike W.
Posts: 386
Joined: Tue Jun 13, 2017 6:59 pm
Car: 2003 Infiniti QX4 with a drinking problem. Gas and oil.
2002 BMW 525it
1998 BMW 328is
Location: California Whine Country

Post

VStar650CL wrote:
Fri Feb 24, 2023 12:02 pm
PS - BTW, if you have them cut at a parts store and not a machine shop, pay them extra to do the lathe passes at the slowest travel speed and a maximum 0.002" per pass. Drill-and-Slot rotors are pretty intolerant of the usual 0.005" one-pass treatment. Professional machinists will usually know better, but the parts guy may not.
Are you finding it cost effective to even surface rotors these days? Mostly living in the BMW world with touchy, shimmy prone front ends, but generally quite affordable rotors, the standard procedure is to just throw away the old rotors and replace with new. Especially at a good machine shop, surfacing isn't cheap, but I would still go there over most parts stores.


Return to “Nissan Pathfinder Forum / Infiniti QX4 Forum”