As most of you are aware, verifying the rotor runout is a key step in performing a proper brake job. Some aftermarket rotor manufacturers (and most Euro OEMs) have begun to coat their rotors on the friction and non-friction areas of the rotor (for rust/corrosion protection) and this is making it difficult to check the rotor runout. The coating on the friction areas feels rough and the needle on the dial indicator will skip, which makes it impossible to get an accurate reading of the rotor runout.
Here is a picture of the rotor in question from a recent brake job I did. This is a Genuine Mercedes rotor that came coated with the aluminum/zinc coating on the friction and non-friction areas.
Untitled by The Critic, on Flickr
There are only 2 solutions that I can think of:
1) Find a way to efficiently sand off some of the coating (to make the surface bare metal again)
2) finish the brake job, go for a test drive, then come back and check the runout.
#2 is a terribly inefficient method. I haven't tried #1 yet.
Does anyone have better ideas? Thanks.
Here is a picture of the rotor in question from a recent brake job I did. This is a Genuine Mercedes rotor that came coated with the aluminum/zinc coating on the friction and non-friction areas.
Untitled by The Critic, on Flickr
There are only 2 solutions that I can think of:
1) Find a way to efficiently sand off some of the coating (to make the surface bare metal again)
2) finish the brake job, go for a test drive, then come back and check the runout.
#2 is a terribly inefficient method. I haven't tried #1 yet.
Does anyone have better ideas? Thanks.