Do you still have to have your rotors turned, even if you don't have any signs of warpage?

I'm due for a first pad change, on a set of brembo blanks with about 36k on them. As you know, these are hard to come by (not even sure you can get them anymore), so I wanted them to last as long as possible.

 

You have to get the glaze off of the rotors when doing a brake job. Depending on who is running the machine they can just bust through the glaze or over due it and start throwing shavings off your rotor. Let them know that you feel your rotors are not warped.

 

You should always turn your rotors when putting on new brake pads. Like Edwardgp said, you need to get the glaze off the rotor. If there is no signs of warping, it should only take a small pass on the rotors. You could do just a pad slap but I've had cars pulsate when braking when doing this, even when it didn't pulsate with the old pads. Its just a chance you would be taking.

 

I get them turned every time I change the pads on my DD truck. I have a good mechanic that is able to pull off the right amount. I'm on my third set and the last set of rotors lasted me 107k, with the truck having 212k on it.

 

Right way is to turn or replace every time.... if they at straight and in spec personally, on my own vehicles, i just replace the pads.

 

I only turn or replace mine when they are warped or too thin as well. Thats what my father always did along with all my friends that do their own work.

If the car stopped fine with the old pads and glazed rotors, then I see no benefit to turning them just cause I replaced the pads. After the change, I always do 4-5 hard stops from about 35mph to make sure everything is ok. If there is any pulsation or vibrations, I get them turned. Only had to do that once or twice though in the last 17 years.

 

I don't turn the rotors. When replacing pads if they are the same exact pad (manufacturer and type) they just get installed.

If changing the manufacturer or type (compound) of pad then the rotors get sanded. Using a 120 grit emery cloth in a circular pattern the build up of pad material gets removed. Install new pads and bed them.

RBob.

 

Right: all they need, usually, is just to bust the glaze.

A quick zip with a Roloc in a die grinder freshens em right up enough for new pads.

 

turning the rotors is a bad idea IMO, the way the rotors are turned and not faces with a rotating cutter creates a groove just like a vinyl LP/phonogrtaph would have, especially with the coarse (quickie) cutting pattern you see on most jobs. This causes the pads to skip severely compromising brake performance.

 

The reason you need to break the glaze is so the new pads can establish a wear pattern, otherwise you get vibration. It usually isn't noticeable until you put a few hundred miles on the pads. The vibration is from the pads fighting the wear of the old pads and trying to make new wear on your rotors. Twin_Turbo, if you've ever gotten rotors back that look like that, I would demand either a refund or for them to turn them again and do it right.

 

You don't get rotors back that "look like that", it's how they are ALL done. Ever notice how new rotors are faced with a cutting/grinding wheel? Very very distinct pattern on the rotorface, that's a non directional pattern. All brake rotor latghes run a single groove over your rotor and I can almost guarantee you that most shops will cut coarse and fast and not do a 2nd cut with a fine pattern over the initital cut. Turned rotors are junk IMO.

 

interesting theories guys. I was going to change from Hawk Ceramic to Hawk HPS, so maybe i'll just give them a quick scrub with sandpaper.

 

Yup same. By the books i agree you should get them turned ever so slightly. But to put it into perspective i just did pads on my camaro last winter and did not turn the rotors because they were not warped and did not have a lip on the edge from wear. The pads were toast though. Stops on a dime with the new Hawk HPS pads.

 

Rotors don't warp. Pads bed a layer of pad material in a fresh rotor surface. This gives you your transfer layer where material is swapped between rotor and pad and energy transfer and conversion (kinetic to heat) takes place. Uneven transfer layers give a pulding sensation that is commonly called a warped rotor.

 

RBob,
Getting ready to change all 4 sets on my 88 (pads).
I was going to just replace the rotor (original), but there is no problem with them.
Do you just sand them by hand to knock off the glaze?
And what do you says for pads? What brand?
Mines a 4 wheel disc Formula 350, 55,000 miles

 

Yes, by hand. I take a square of emery cloth and flattening out the hand swirl the cloth across the rotor. Slowly rotate the rotor while swirling. Do both sides until there is a nice even pattern.

I'm partial to the StopTech Street Performance brake pads. They are on the high end of the FF range.

RBob.

 

I use those pads too RBob.. Actually I think you recommended them to me a couple years ago lol. Thanks haha.. They are pretty sweet.

 

I don't recommend turning rotor unless the rotors are warped.