Classroom misinformation on brake rotor replacement procedure

FLIGHTOPPS

MEMBER
2007 BUICK RENDEZVOUS
4.5L
6 CYL
2WD
AUTOMATIC
121,000 MILES

I am an automotive student an a NATEF certified school.
I am taking a refresher course to catch up on new Hybrid technology. I have been a paid mechanic for forty five years on and off, but work in engineering currently.

I had an instructor allow a student to do a pad slap. Only scuffing the old rotor (that was significantly blued) with a red scuff pad by hand. The statement was that is an industry standard, and it satisfactory, what? So I pose the question. Just who's standard is that, and where is it written? I was taught forty plus years ago if I ever change a pad, the rotor either gets cut or replaced. No exceptions! Help?

Scott

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning.

You are from the same school as myself. There are times you can get by with just a hang and bang, but usually will end up with pulsations and premature wear on the pads.

Today's rotors have no thickness to them anyway. It does not pay to cut them as they will be undersized. In any brake job today, rotors are replaced as part of the job to make it a proper repair. The scuffing he talks about goes away in about five miles of driving. The glaze is a major reason for brake squeal as well.

His information may be as old as decades ago when we had very thick rotors and drums.

Roy