Sanded Rotors

[Donald]

If you're going to do it, at least use the right tools for the job,

This are the right tool to remove the glaze. Or a wire brush.

You are not going to smooth out the rotors with any tool other than a brake lathe. And after turning the rotors one needs to measure for minimum thickness.

These days most people just slap on new pads to do a cheap brake job or replace pads and rotors to do it properly.

 

[willbur]

If you're going to do it, at least use the right tools for the job,

What is the grit "rating/number"?

 

[KrisZ]

The brakes will be fine, I’ve done it myself few times in the past when just replacing the pads with no negative effects. Although I did it by hand so the scratches were not as deep.

It will just look ugly, that’s about it.

 

[brages]

What is the grit "rating/number"?

P120

 

[willbur]

P120

Thanks- got some

 

[Hohn]

To be effective, you need a real machine to machine the rotors, preferably an on-car brake lathe.

That sanding might be worse than not sanding them at all

The sanding marks should've gone away within the first few stops!

Also, I see your rotors are already rusting. Next time get coated rotors

The best machine for rotor resurfacing is a Blanchard grinder because of the surface finish it leaves. (This is why it's also the machine of choice for flywheels that will see clutch contact).

But I agree that the scratches are inconsequential (consider the slotted and drilled rotors many buy on purpose!). I also agree that if you want to help your friend, just give him cash.

 

[Hohn]

I'm not the one who did it but I'm pretty sure my buddy who did the job used regular sandpaper disks, probably 60-80 grit or something like that.

The reason rotors should never be sanded or abraded by hand is that you cannot keep the surfaces flat, parallel to each other and normal to the axis of rotation. Hand work will inevitably lead to low spots that lead to uneven wear.

 

[Gus_Mahn]

Old wives tale. Smoother is better for all rotor finishes. Have you seen how smooth the rotor finish is on new Genuine Toyota rotors?

I think that generally you’re correct, but I’ve owned a couple of cars with gigantic brakes with opposed piston calipers. On those cars, even with new OE rotors and OE Brembo pads, the brakes are awful for a couple of hundred easy miles. I can see where a little tooth on the rotor would help to bed the pads to the rotor. I’d do a proper 10 stop bedding, but that just isn’t easy where I live.

 

[Tman220]

Those rotors are fine. As long as it brakes smooth don't give it another thought. If you want your rotors perfect, then supply them to the mechanic next time.

That mechanic was probably just trying to make the best of a bad situation YOU put him in anyway by not supplying new rotors, an independent guy like that certainly doesn't have a brake lathe and you probably didn't want to wait for your mechanic to find the nearest place to have them cut.

 

[ZX11Rebel]

Most of the Chilton-Haynes manuals I’ve ever seen recommend scuffing up the rotor when installing new pads.

 

[97prizm]

I've driven about 40 or 50 miles and they're still there. So, you don't think the rough surface will make the brakes wear quicker?

I'd be concerned about stress cracking if the sanding marks are still there

 

[barryh]

The last set of new Bosch rotors I fitted were coated. Never having used coated rotors before I thought this was going to be positive attribute that kept the rotors rust free on the upswept areas and that it would be designed to quickly wear off on the swept area or perhaps even aid the pads bedding in. In fact the coating was just silver paint and not a very thin coating. The initial braking performance was positively dangerous, so much so that I pulled the wheels after the first journey and sanded the swept area back to bare metal by hand. I won't fit painted rotors again without first removing the paint.

 

[Kantaro]

Seems like something from a scottykilmer video

 

[bdcardinal]

There are flex hones specific for brake rotors like the Matco RFH60. I have one and when I turned wrenches I would give the rotors a whiz with them after cutting them on a lathe. To be fair, the lathe we had at Sears was ghetto at best.

 

[thejon]

Thanks for all the replies, I really appreciate your help. I've decided to go ahead and replace the rotors. Even though many here have mentioned no real damage was done, I just can't stand how ugly they look. Last question: Should I "bed" the brakes again with the new rotors or is that only a procedure used when putting new brakes on old rotors?

 

[spasm3]

Thanks for all the replies, I really appreciate your help. I've decided to go ahead and replace the rotors. Even though many here have mentioned no real damage was done, I just can't stand how ugly they look. Last question: Should I "bed" the brakes again with the new rotors or is that only a procedure used when putting new brakes on old rotors?

Really, unless the brake pad manufacturer recommends a bed in procedure I wouldn't.

I am under the impression that (new) track pads need to be bedded in, so they outgas before you are on the track and hard braking in a turn.

@TiGeo might have track experience to relay.

 

[meep]

Thats a easy way to remove the glaze from the rotors. They actully need more sanding to be more uniform. Those that are saying its a wrong way have never seen a new rotor and what it looks like.

This. It can remove glazing and address some squeal issues, but it would need to be more consistent and finer grain. Right idea, perhaps not elegantly done. Not throwing shade on your friend, but it suggests undisciplined or inexperienced or out of touch with what’s happening.

Did he grease the slider pins, did he bleed in new fluid?

 

[bobdoo]

Thanks for all the replies, I really appreciate your help. I've decided to go ahead and replace the rotors. Even though many here have mentioned no real damage was done, I just can't stand how ugly they look. Last question: Should I "bed" the brakes again with the new rotors or is that only a procedure used when putting new brakes on old rotors?

Rust would have formed in those scratches. They are way too deep. The rust would have quickly destroyed the surface. Well-in the rust belt!

I always bed in new pads. You want max braking from the first mile. You won't get that till pad material covers the disk, and the pads contour to the wear of the old disk.

 

[Skippy722]

Thanks for all the replies, I really appreciate your help. I've decided to go ahead and replace the rotors. Even though many here have mentioned no real damage was done, I just can't stand how ugly they look. Last question: Should I "bed" the brakes again with the new rotors or is that only a procedure used when putting new brakes on old rotors?

In your case I would definitely bed them in, the new rotors won’t have any pad material on them.

 

[thejon]

This. It can remove glazing and address some squeal issues, but it would need to be more consistent and finer grain. Right idea, perhaps not elegantly done. Not throwing shade on your friend, but it suggests undisciplined or inexperienced or out of touch with what’s happening.

Did he grease the slider pins, did he bleed in new fluid?

He did grease the slider pins and bleed the fluid, yes.