SL/R230: High-Pitch Squeak
Thread Starter
Junior Member
Joined: Jan 2013
Posts: 58
Likes: 6
From: Memphis, TN Metro
2017 SL550
High-Pitch Squeak
2009 SL550. Lately, I've been hearing a very high-pitch squeak, almost a chirping, coming from the front end area. Dealer service dept. had it in for a bad battery, and told me "your front rotors are too small diameter and so the pads are wearing with the top of the pads riding over the rotors. This is the noise you're hearing." Sounded plausible.
I had a friend's brake shop look, and they found this WAS the case, I suspect from the previous owner getting the brakes and rotors replaced and his shop sourced some rotors that FIT, but were smaller diameter. So my guy put on new pads and the CORRECT size rotors. After a few days, the high-pitch squeak has returned. It is never dependent on braking, turning, or going over bumps (suspension). But only when moving. I can be driving in a straight line, on smooth road, and it will squeak very randomly. Parked and turned off, I CANNOT make the squeak by bouncing the suspension or any other movement. ESP triangle light is illuminated (probably a wheel speed sensor) but I believe that is unrelated. This COULD still be brake-related, like hardware or caliper pins/bolts, but with brand new pads and rotors, everything inside the calipers should be fairly tight. THIS IS NOT a standard brake squeal.
If anybody has heard this type sound or has any thoughts, I'd appreciate any thoughts.
I had a friend's brake shop look, and they found this WAS the case, I suspect from the previous owner getting the brakes and rotors replaced and his shop sourced some rotors that FIT, but were smaller diameter. So my guy put on new pads and the CORRECT size rotors. After a few days, the high-pitch squeak has returned. It is never dependent on braking, turning, or going over bumps (suspension). But only when moving. I can be driving in a straight line, on smooth road, and it will squeak very randomly. Parked and turned off, I CANNOT make the squeak by bouncing the suspension or any other movement. ESP triangle light is illuminated (probably a wheel speed sensor) but I believe that is unrelated. This COULD still be brake-related, like hardware or caliper pins/bolts, but with brand new pads and rotors, everything inside the calipers should be fairly tight. THIS IS NOT a standard brake squeal.
If anybody has heard this type sound or has any thoughts, I'd appreciate any thoughts.
Member
Joined: Aug 2007
Posts: 76
Likes: 7
Not sure if this will help or not but I had a similar noise that could not be replicated regardless of how I tried. I had a separate failure of motor mounts, once replaced the squeak was gone. Rule of thumb, metal on metal is usually a squeak. You seem to have thrown enough new parts at the brakes, do the motor mount check. Hood open in gear gas and brake applied see how much movement you get. Good luck, and you can always turn up the stereo.
Thread Starter
Junior Member
Joined: Jan 2013
Posts: 58
Likes: 6
From: Memphis, TN Metro
2017 SL550
Thanks much but new motor mounts last year. Ride improved immensely once they were changed out. Will probably return to friend brake shop with hardware and shims and get caliper bolts/pins lubed and see if it quiets things.
Thread Starter
Junior Member
Joined: Jan 2013
Posts: 58
Likes: 6
From: Memphis, TN Metro
2017 SL550
Thanks "SLCharge", wheel bearings are fine. I have isolated the problem and fixed it. My tandem pump was a little low so I added some fluid and it has totally eliminated the squeal. I guess it's true what they say—the revised ABC system is MUCH more resilient, because I have not experienced any performance problem or symptom, just the noise.
Hey, your 408hp tune, is the difference in power very noticeable? Got any pics of your custom exhaust, or where sourced/brand?
Thanks much!
Hey, your 408hp tune, is the difference in power very noticeable? Got any pics of your custom exhaust, or where sourced/brand?
Thanks much!
