Weird noise after RB rotor/pad install
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Joined: Feb 2016
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From: Oviedo, FL
2015 C63s Sedan
Weird noise after RB rotor/pad install
So I installed racing brake 2-piece f/r rotors and pads a month or so ago. Did a complete fluid swap with motive bleeder and had no issues during the install. Since the install, I'm getting a weird noise from front D/S, it goes away when I apply the brake slightly and it's the loudest when cold.
Jacked it up and spin the wheel and it's like the piston(s) are not retracting and the pad(s) are making slight contact with the rotor only in one section of the rotor. I removed everything again cleaned the hub to ensure the rotor was flush and still making the same noise. Could it be a stuck piston, air in that particular caliper, or a warped rotor? Any input would be appreciated.
Dan
Jacked it up and spin the wheel and it's like the piston(s) are not retracting and the pad(s) are making slight contact with the rotor only in one section of the rotor. I removed everything again cleaned the hub to ensure the rotor was flush and still making the same noise. Could it be a stuck piston, air in that particular caliper, or a warped rotor? Any input would be appreciated.
Dan
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From: Oviedo, FL
2015 C63s Sedan
I was thinking the same, but it only seems to make contact with the rotor in a small area when spun. Makes me think maybe the rotor has an excessive bit of run-out.
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From: SWF
2020GLC63
Just did my front brakes today So far so good but didn't' bleed or replace fluid. Wondering what you use to compress the pistons? Any chance they were compressed on an angle damaging the seals? Are you leaking brake oil? Wondering if it air bound also.
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From: Oviedo, FL
2015 C63s Sedan
No visible leaks on that caliper, I pulled that side back apart after a couple weeks of driving. Thinking maybe I'll bleed that side again, if that doesn't work maybe have the rotor lightly skimmed at my local machine shop.
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Thread Starter
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Joined: Feb 2016
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From: Oviedo, FL
2015 C63s Sedan
On past cars with multi-piston calipers, I've never had any issues when changing pads or rotors. I didn't think you could really "service" them, as either you rebuild them or not. There are no visible leaks from any of the pistons, but maybe will look at rebuilding them with new pistons/seals.
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2009 SLK55 AMG. & 2022 GLA250 4Matic
On past cars with multi-piston calipers, I've never had any issues when changing pads or rotors. I didn't think you could really "service" them, as either you rebuild them or not. There are no visible leaks from any of the pistons, but maybe will look at rebuilding them with new pistons/seals.
One was glaze on the brakes because we tend to not use the brakes hard in normal day to day driving and they glaze. The other is since my car was sitting for 9 weeks while I was down south the crud on the slides may be hardened up and the calipers need to be serviced which is basically a cleaning of the slides and rails. Just saying. I also like the idea that there may be a bit of rotor warpage.
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From: Oviedo, FL
2015 C63s Sedan
Our calipers are fixed, there are no slide pins. The only movable parts are the actual caliper pistons. Sent a note to RB for their thoughts as well, as I don't want to throw $$ at it if it's not going to fix it. Everything was nice and quiet until I did this swap 
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From: Oviedo, FL
2015 C63s Sedan
Update: I installed RB's complete front caliper rebuild kit today, new pistons and seals. All seems to be nice a quiet now, sanded down pads and did the bedding process again. Thanks to all for reply, this forum is very helpful.... for technical stuff.....
