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New rear rotor turning blue?

Just replaced my rear rotors/brake pads. Went with ceramic pads. Drove it and it all seemed fine. Got home and noticed one rear rotor turned blue near the base section where the studs are. Like a ring around the whole base, but not where the pads make contact. Is this normal or is something wrong? Any help would be much appreciated. I included a picture of what it looks like

The rotor got extremely hot.

Tester

Right I get that, but only one rotor did it. The other side looks completely normal. Could it be a faulty rotor? Or am I just missing something

drive a couple of miles not using brakes much, then park and CAREFULLY check wheel hubs first, then rotors for temperature

if one is cold as stone and another one is hot, you have sticking caliper issue

2 Likes

Sticking caliper?

Bad caliper hose?

Tester

Make sure the caliper isn’t sticking and the brakes dragging.

Okay I popped off the caliper and tried moving the 2 slides. They do both seem to be somewhat sluggish when trying to move them back and forth. If that’s the case is it okay to use this rotor still?

The metal was heat stressed.

The rotor could crack in that area.

Tester

Just to cover everything how do I check the caliper hose?

Pump the brake pedal few times and then open the bleeder screw for that caliper.

If brake fluid shoots out the of bleeder, that caliper is still under hydraulic pressure even though the brake pedal isn’t being depressed.

Tester

Just drove it around after greasing those pins, wasn’t near as hot so I think that was it! Thanks for the help

Did you clean the protective coating from the rotor before installing it? It looks like the protective film turned purple from the heat.

I sprayed it with brake cleaner and wiped it down before the install, but that was it

I think the recommended method is to clean the new rotor surface with hot water and soap and a scrub brush. But what you did was probably good enough. I don’t think that’s the cause for the blue rotor.