nc211 Posted March 29, 2007 Share Posted March 29, 2007 I tivo Motor Week, and on one of the Goss's Garage segments, he demonstrated how to smooth out the surface of a new set of rotors. He used a pnumatic grinder / sander with about a 2 inch circular piece of sandpaper. He gently applied the pad to the rotor and proceeded to go around the rotor's surface. He said this will allow the pads to groove the rotor to thier own liking. I just bought some new rear rotors, and they have a criss-cross pattern to them, which makes a horrible hissing noise at parking lot speed. Anyone ever does this to their rotors before? Any advice or input on technique? Quote Link to comment Share on other sites More sharing options...
W201 sweden Posted March 29, 2007 Share Posted March 29, 2007 I have from time to time "re-vitalized" old, and worn discs using a similar method. A normal electrical drill with sandpaper on. Even after having sanded off quite some metal, it has always worked very well with the new pads. No noise or vibration, as long as the discs were not warped before... :) /Alexander Quote Link to comment Share on other sites More sharing options...
SRK Posted March 30, 2007 Share Posted March 30, 2007 If new rotors need any work before installation, I'd buy a better brand. I am still not sure about that guy Goss - I know he has a career in automotive behind him, but sometimes.... I bought new Lexus rotors for my LS, and they were cheaper than the Raybestos ones. They had a ground surface finish, not machined, and were works of art. Cleaned the rust preventative off and bolted them on. The brake pads will always smooth a rotor to their liking after a few hundred miles. I had the occasional customer touch a pad backing plate to the rotor before realizing they needed new brakes. Many times I just slid new pads in and ignored the rather nasty looking ring of mangled metal on the rotor surface. Every test drive ( and I test drove my brake jobs for at least five miles) proved that the rotors were fine, no noises, no uneven braking. My advice is to do a few miles of gentle normal braking, and then get on them hard a few times. That will do it. Quote Link to comment Share on other sites More sharing options...
LScott400 Posted March 30, 2007 Share Posted March 30, 2007 I'm with SK on this. NEW rotors should already have the proper micron finish for seating to the new pads. They will also have the non-directional finish which is the result of the circular sanding you described. We called the seating of new brake pads/shoes "burnishing". Brake_Burnishing_Procedures.pdf I have read many comments about slotted rotors making that hissing sound, so I would have to believe it is the nature of the beast. Quote Link to comment Share on other sites More sharing options...
nc211 Posted March 30, 2007 Author Share Posted March 30, 2007 i noticed this morning the hissing sound has died down quite a bit, we've had some rain lately, and I think the water splashing on the rotors helped seat the pads a bit, or, like mentioned earlier, I'm getting to the point of wearing them in. They probably have 500 miles on them now, with somewhat city driving. They'll seat, I'm confident of that. I just refuse to buy oem rotors, especially for the rear. I just can't justify the expense in my own mind, especially when there are sooooo many other premium brands out there for 40% the cost. I know rotors aren't just "rotors", and everything doesn't taste like chicken, but geezzz are Toyota rotors expensive, and will warp too. Quote Link to comment Share on other sites More sharing options...
SKperformance Posted March 30, 2007 Share Posted March 30, 2007 Any good rotor will already have the finish cross cut by a mchine for an even level but still rough finish. Quote Link to comment Share on other sites More sharing options...
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