brake rotor cleanup?

[Mud]

Maybe I'm nuts but I've been mulling over if it would be feasible to have an electric motor set up with a plate/adapter to support and spin a brake rotor. In most cases when I replace pads the rotors are not damaged or warped so I don't see a need to re-cut them. However, it seems like a good idea to to me to at least do a sandpaper pass on the surfaces just as a clean-up for the new pads.
I was at Brake Check getting an alignment and I think I saw one of their guys doing this on a similar setup, except he was using an air sander. The machine was set up horizontally but I was thinking to place the motor vertically so that the rotor would be spinning like a turntable. I could then use a sanding block to evenly clean up the surfaces.

Is this delusional?

 

[Kestas]

Your idea may work if you don't plan on removing too much material. It'd be like "honing" the rotors.

I toyed with the idea of trueing rotors and drums on the lathe we have at work. I couldn't assure myself that I'd chuck the rotor without any wobble, so I scrapped the idea.

 

[SZR48207]

Wouldn't this be kinda sorta like getting the rotors turned? I would worry about keeping the rotor true and preventing runout or low spots from sanding. Then again all china rotors are pretty cheap nowadays.

 

[Eddie]

I use a sanding pad on an electric drill to get the gloss off.

 

[David S.]

Maybe the machine that was seen is the one that Pat Goss talked about on Motorweek?

http://www.mpt.org/motorweek/goss/2609.shtml

For my cars most of them use rotors that cost $15 to $20 new so I simply replace them rather than getting them "turned."

 

[ARCOgraphite]

The wheel spindle is true and the caliper bracket makes a good tool rest - no want or need to take the rotor off. For "budget" brake jobs, I use a grinding wheel on my drill to scuff up the surface and get off the rust on the edges and make a nice chamfer. Results have always been BETTER than with new rotors.

 

[Mud]

Thanks gents. My intent was not to take off a lot of material. just to give a freshly cleaned surface for the new pads. I was thinking that the motor would provide the ability to turn the rotor to keep the sanding pad steady for less effort on my part. I don't think that hi or lo spots would be an issue for such a very mild cleanup, probably using 220 and/or 400 grit paper.

I use NAPA rotors on almost all of our vehicles but they are more expensive than $15-$20 and I don't see that I need to change them out at every brake job if they are within spec. I typically change the pads when there is still some meat left on them and the rotors are fine so I think only a mild cleanup is needed.

I've seen those machines, but those are for taking off much more material than I am describing here. I think I will mess with this a bit to see if works like I think it should.

 

[defektes]

If I do not turn my rotors I sand them with a electric orbital sander to remove the glaze and leave a nice non-directional finish.

 

[Jim T]

I use one of these

http://www.americansportbike.com/shoponline/ccp0-prodshow/16055.html

I built a turntable out of a lazy-susan bearing and spin the rotors on it while "honing" them with the tool mounted in a medium speed battery drill. I use it for both car & bike rotors and they work real nice.

Jim

 

[SLCraig]

Rotors are even cheaper than pads.. If there's a problem, for the $20 or whatever, I just install new ones.. Too much thought over something so cheap and yet so important

 

[Jim T]

Yes well if it isn't warped or worn WHY replace it? I've never seen a truly warped rotor. Only ones with pad residue on them making people think it was warped.
Besides the front rotor on my Buell is $150.
All four on my Mazdaspeed3 are over $250.00 but why replace them if they are still in spec?

Jim

 

[ARCOgraphite]

Originally Posted By: Mud
... I don't think that hi or lo spots would be an issue for such a very mild cleanup, probably using 220 and/or 400 grit paper.

...
You dont use sand paper or emery cloth in this application/machining. Use either a hard tool or a grinding wheel. It also good to slot and (leading edge chamer) the pads if they are organic to allow more gas venting. You can use a file and a hacksaw for this.

 

[mopar_monkey]

Originally Posted By: Jim T
I use one of these

http://www.americansportbike.com/shoponline/ccp0-prodshow/16055.html

I built a turntable out of a lazy-susan bearing and spin the rotors on it while "honing" them with the tool mounted in a medium speed battery drill. I use it for both car & bike rotors and they work real nice.

Jim


x2 these work great and last a long time, i use the medium grit one for every brake job i do in my shop that is'nt getting rotors.

 

[Mud]

Originally Posted By: mopar_monkey
Originally Posted By: Jim T
I use one of these

http://www.americansportbike.com/shoponline/ccp0-prodshow/16055.html

I built a turntable out of a lazy-susan bearing and spin the rotors on it while "honing" them with the tool mounted in a medium speed battery drill. I use it for both car & bike rotors and they work real nice.

Jim



x2 these work great and last a long time, i use the medium grit one for every brake job i do in my shop that is'nt getting rotors.


That is exactly what I was looking to do, thank you! I had the same idea about the lazy-susan except I was going to do a lazy-mud and set up the rotor to spin with an electric motor

Just a way to freshen up the surface as I don't have those $20 cheaper-than-pads rotors