New brake rotors


#1

I’ve heard some pro’s & con’s on “dressing” new brake rotors before installation. Any feedback. (with installing new brake pads, also.)


#2

New rotors should be thoroughly washed with brake or carburetor cleaner as many of them may have a film on them to prevent rust.

If you use carb cleaner I would suggest Berryman B12 or even the WalMart brand of cleaner. Some cleaners, such as Gumout IMHO, seem to have a wisp of oiliness to them that I don’t particularly care for.

I always use a grinder to bevel the leading and trailing edges of new brake pads also. Some pads are already beveled and others are not. This can help to prevent a bit of chatter or squeal.

Clean and lube the caliper slide pins and make sure the caliper pistons are not extremely difficult to retract.
And as always, when done be sure to pump the brake pedal a dozen times before you go sailing out of the drive. Hope that helps.


#3

Few years back had one “brake guy” say that new rotors should be put on the machine & lightly turn a little off to check for trueness, and take off film at the same time???


#4

Given the fact that most of today’s replacement rotors are made in China, truing them up before installation probably would not hurt anything…

I also suspect few shops take the time to do this.


#5

Well, I’ve never had the need to machine a new rotor or seen one that needed it.
If one did that the price of the brake job is going to go way up also as you could probably figure a minimum of .5 an hour shop flat rate time to cut a new rotor. At 70-80 bucks an hour - ouch. Many flat times may specify a full hour for cutting one rotor, but I’m assuming .5 here just to brush them a bit.
Still pointless IMHO.

I question, a lot, that bit about using machining to remove a rust preventative film.
If one attempted this the film would just gunk up on the carbide cutting bit and be rubbed back off onto, or INTO the rotor, which would then lead to cleaning it anyway.


#6

That’s got to be ultra cheap products. Rumors floating around that some of the brake rotors being sold on the aftermarket are dangerous. As you know, a product which failed quality check is supposed to be dumped. So there might be plan B.


#7

I’m about to put new brakes on my Saturn. I’m trying a new brand called EBC. They just arrived yesterday. The rotors are covered in a zinc coating to protect then from rust and the pads, already beveled, have an abrasive coating, like sand paper, that is supposed to “dress” the rotors. They are not cheap.

I have never had to true up new rotors. I do clean off any oil that might be on them, but thats it.


#8

You can get the same effect with steel wool. Most of us don’t have a grinder; I wouldn’t use a hand grinder for fear that I’d destroy the flatness.


#9

Why would you make new rotors thinner and therefore more prone to warping?

Just put the rotors on the car. You don’t have to turn them, clean them, pray over them, sacrifice a bunny to them. . . Nothing. They’re fine out of the box. Any film they may have on them will be taken off the first time you brake. And since the first time you brake is supposed to be testing the brakes to make sure you didn’t do something silly like leave a bleeder screw open, you shouldn’t be in a situation where brake failure is dangerous.