S550 Rear brake caliper issue? Weird pad deposit with new pads

[MinDseTz]

First, the pads are brand new and both rear rotors were turned. I've been having a weird 'pop' or 'creak' sound from my driver side rear for a while (before and after new pads/rotors). I'm stuck trying to figure out the noise but I noticed a difference in the patterns left on the rotors. Also, I regreased all the slide pins in case that was the issue. It looks like the top portion of the rotor with the issue is bouncing or something? Anyone have any ideas?

 

[TMSBOSS]

You may want to look at the bearings and or half shafts for the noise. The rotors look fine.

 

[MinDseTz]

You may want to look at the bearings and or half shafts for the noise. The rotors look fine.

I forgot to say, the noise only occurs when coming to a stop or accelerating from a stop. Wouldn't those sound different and more constant? I can be in neutral, hard or soft accelerating.

 

[TMSBOSS]

Did you "Bed" the pads to the rotors after install?

 

[MinDseTz]

Did you "Bed" the pads to the rotors after install?

This is the result of bedding them. As you can see 1 of them is consistent and relatively uniform, but the other is not. And yes, I repeated the process and drove around for a week or so. The sounds were apparent before and after I replaced the pads/rotors.

 

[JDee]

Were these rotors turned on a brake lathe? The marks on the outside of the rotor in the bottom pic look like grinding marks. I've never seen a lathe turned rotor with a pattern like that. It also looks like the pad is not making contact properly across the disc surface.

Personally, for track duty I'm not a fan of using rotors that have been used and "reconditioned" through whatever process. They get an absolute ton of heat and a rotor failure is likely going to be catastrophic.

 

[MinDseTz]

Were these rotors turned on a brake lathe? The marks on the outside of the rotor in the bottom pic look like grinding marks. I've never seen a lathe turned rotor with a pattern like that. It also looks like the pad is not making contact properly across the disc surface.

Personally, for track duty I'm not a fan of using rotors that have been used and "reconditioned" through whatever process. They get an absolute ton of heat and a rotor failure is likely going to be catastrophic.

They were turned at Oreilly, but I’m not sure what they use. Im not planning on using these rotors o the track, it was more of a troubleshooting attempt.

Is there any reason why this pattern could occur on both sides due to an issue with the caliper? It’s just a single piston floating caliper (stock s550 rear).

 

[MinDseTz]

They were turned at Oreilly, but I’m not sure what they use. Im not planning on using these rotors o the track, it was more of a troubleshooting attempt.

Is there any reason why this pattern could occur on both sides due to an issue with the caliper? It’s just a single piston floating caliper (stock s550 rear).

Also in case anyone is wondering, the pattern is the same on the backside of the bottom rotor

 

[JDee]

I'd be looking for something bent, misaligned, sticking or severely worn in the caliper mounting system. That's all I can think of that might cause it.

 

[TMSBOSS]

Ford had an issue with bearings and spindle nuts loosening. This may be a possibility also.

 

[flyhalf]

I would buy new rotors.
They are cheap.
Also what mode do you use on track.?