Intermittent humming noise while braking
Thread Starter
Newbie
Joined: Sep 2009
Posts: 2
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1995 E320
Intermittent humming noise while braking
Hi,
I had the unfortunate pleasure of having Pep Boys work on my brakes, and they created more problems than they set out to solve. I seem to have most of the problems rectified at this point (thanks to a great independent mechanic in Philly), but am left with a nagging noise that I cannot figure out. Unfortunately, it happens only intermittently and my mechanic can't tell me what he thinks it is because he hasn't heard it.
It occurs at the end of my braking as I'm coming to a complete stop, and I can only describe it as a humming noise that sort of has a crescendo as the car finally stops. It seems to be coming from the left front wheel, and as it happens the brake pad feels like it depresses a little more under my foot, which is disconcerting. The car has never failed to brake on me eventually, but on days where the sound is there it happens almost every time I brake. It doesn't occur early on when I depress the brake pad, but only at the very end.
I wondered if it could be something to do with a messed up ABS sensor? My mechanic wondered if it could be a relatively innocuous problem with the transmission?
I'm stuck. Would appreciate any suggestions.
I had the unfortunate pleasure of having Pep Boys work on my brakes, and they created more problems than they set out to solve. I seem to have most of the problems rectified at this point (thanks to a great independent mechanic in Philly), but am left with a nagging noise that I cannot figure out. Unfortunately, it happens only intermittently and my mechanic can't tell me what he thinks it is because he hasn't heard it.
It occurs at the end of my braking as I'm coming to a complete stop, and I can only describe it as a humming noise that sort of has a crescendo as the car finally stops. It seems to be coming from the left front wheel, and as it happens the brake pad feels like it depresses a little more under my foot, which is disconcerting. The car has never failed to brake on me eventually, but on days where the sound is there it happens almost every time I brake. It doesn't occur early on when I depress the brake pad, but only at the very end.
I wondered if it could be something to do with a messed up ABS sensor? My mechanic wondered if it could be a relatively innocuous problem with the transmission?
I'm stuck. Would appreciate any suggestions.
Senior Member
Joined: Apr 2008
Posts: 405
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From: Forethill, Ca Northcal
85 euro w124 300d non turbo black on black......coming soon hx35 turbo intercooler
Did they take your rotors off? My bad wheel bearing hums maybe they took your rotor off and loosened the bolt and left it loose? Just a guess.
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,297
Likes: 1
From: Connecticut, New Haven
95' AMG SeeThreeSix
If this noise ONLY persists upon letting off of the brake pedal after your initial braking I could suggest that the brake line hoses tend to swell up inside after a while. This in turn restricts the fluid, not so much when you press the pedal to actually brake but when you take your foot off of the pedal the caliper piston stays pressurized until the fluid drains back through the line. I had a severe case of this, my rotors were heating up bad and humming. Try to take a spirited drive, braking, accelerating then pull over and squeeze a plastic bottle of water through the wheel openings, listen for a sizzle and then see steam. If not it may not be bad. Also, check your caliper bolts, just in case.
Junior Member
Joined: Jul 2009
Posts: 15
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1986 300e
at low speeds my ABS goes off causing unpleasant braking. Especially when going slow or down hill slow. I made a thread about this problem once and i was told to just disable the abs. Does anyone know how to do this? the braking is veryyy annoying and its is definitely not correct for this to be happening.
Thread Starter
Newbie
Joined: Sep 2009
Posts: 2
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1995 E320
Thanks
They did take the rotors off, but I had my mechanic look for loose bolts at one point. I'll try to see if it's a brake line hosing thing, but it doesn't occur as I'm letting up off the brake pedal, it happens right as the car is coming to a complete stop when I'm still depressing the pedal.
Thanks for all your help.
Thanks for all your help.
