My brakes are squealing EVEN WHEN I'M NOT USING THEM! What's going on? What can I do?

Some background:
I'm using Ferodo DS2500s. They've been on for about 600 miles. They've been used on the track once. A day or so after the track day, I developed a squeal in what sounds like the right rear brake when lightly braking. It's really loud. I took the right rear brakes off to put more anti-squeal on the backs and I let it cure overnight. I put the pads back on. The squeal came back as soon as the brakes got up to temp...about 5 minutes of city driving. Now I have a squeak squeak squeak squeak when I'm at low speeds (0-25 mph) even when I'm not applying the brakes! Sounds like it's coming from the right rear, of course.

I posted this in another thread after removing the pads, but didn't get a response:
It seems like just normal brake usage (no e-brake usage, mind you) causes my rear pistons to extend, but they NEVER RETRACT. Is this normal? It just doesn't seem right. If it is normal, then my pads are constantly touching the rotors? This doesn't make any sense to me. I really really need help, and I realize that my dealer isn't going to offer me any, since I put on non-MINI pads, and I did it myself. This car sounds horrible now, and I'm embarassed to be seen driving around in it!

 

I just called the dealer to ask one of the service guys' advice. He basically told me that yes, the brakes do basically ride right up on the rotors all the time--that's just what they do, and "that's why we only recommend BMW stock brakes." I do still have my stock brakes, so I might just put those on the rears for now and then change them out prior to track days. This is really weak, though. And yes, I had heard that the Ferodos might squeal, but I can't believe that there's nothing that can be done about it. I suppose I could try putting a serious pile of plastic goo on the pad backs and see if that would fix it, but I'm very doubtful.

This sucks.

 

I had squeeling with my Ferodo DS2500s too (although not when I wasn't applying pressure to the brake pedal). They were very squeel sensitive. Even after attempts to chamfer the edges of the pad to knock of a suspected burr, they still squeeled. I finally reached my limit with the squeeling and now have the stock pads back on the car.

 

Ugh. What a waste! I really don't want to do that.

 

I have EBC Greens on my 04 mcs and they will squeel a little under lite braking but, not all the time. I'd suggest that you try using an anti-squeel paste on the back of the pads. I heard that the one made by CDC is very good. Saw that on another post here awhile back.

 

Thanks apexer, but that's just what I did yesterday, trying to get rid of the original light braking squeal. Now that I've done that, I have the new and improved always-on-super-squeal. And it's not just at low speeds, as I thought previously, it's now at any speed. It just whistles right along, sounding like a beat-up Yugo as I zip to work in my fancy German coupe.

 

All disc brake systems basically keep the pads riding against the rotors when not braking, there is just not any pressure being applied to them. This is normal, since any 'retracting' of the pads results in increased pedal travel. In actuality, there is the slightest bit of built-in 'retracting' that occurs when the brake piston seals which become squeezed outward by the fluid pressure. When the pressure is released the rubber sealing rings relax back into the bore, and pull the piston with it. It's only a couple thousandths of an inch at most. The anti-squeal compounds help by taking up slack between the pads and the pistons/calipers and deaden any slight vibrations.

Most of the harder, race-type pads have inevitable squeal, sometimes it can be lessened by using drilled/slotted rotors.

 

>>Thanks apexer, but that's just what I did yesterday, trying to get rid of the original light braking squeal. Now that I've done that, I have the new and improved always-on-super-squeal. And it's not just at low speeds, as I thought previously, it's now at any speed. It just whistles right along, sounding like a beat-up Yugo as I zip to work in my fancy German coupe.
>>
>>

Perhaps if you called it your 'fancy British coupe.'
it would stop squealing?

 

I have the same problem. My brakes are stock though, and it is more of a grinding sound. Sounds like I have to make an appoitment with the dealer...

 

If anyone has a trick that works really well to keep the noisy squeal down on aftermarket "track" brake pads besides removing them please let us know.
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I did find this:
http://www.bimmerparts.net/techt/bmwtbrak.htm
The article mentions:
In order to dampen brake system vibration, you have four options to consider: chemical insulating compound on pad backs, shim insulators between pad backs and the caliper, high-temperature grease on caliper pins, and in some cases, OE damper weights.
And they even discusses "sanding the rotors"!
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Funny, I put on Mintex Redbox pads and they work just great- wears well, stops good, less brake dust, doesn't cost that much and never squeals front or back-ever. It's more of a street pad and not for the track like the Ferodo DS2500 although Mintex does make other track worthy pads (they cost more though)- sold at Helix13.

I hate the dusty OEM pads- I had to clean my wheels twice a day or they'd turn black. Now I wipe down my wheels once a week. Pretty good. I have so much free time now!

_________________
ALOHA

 

Chitown_COOP: Could it be something besides the brake pads squealing? I believe there are wear sensors in the rear... could they be bent or something and scraping against the rotors? Some other part rubbing? the wear pad sensor probably sounds just like brake pad squeal... There are a number of people running the 2500s all around, and this is the first complaint of squeal without the brakes being applied

I think all disc brake system have the pads right up against the rotors (not just the Mini)... however there is a thin layer of air between rotor and pad when the wheels are moving... the pads dont touch the rotor when everything is working properly... otherwise the pads would all wear out even if the drive *never* applied the brakes?!

Finally, on anti-squeal compound, this is designed to stop vibration induced noise/squeal... not "race pad" squeal... which is caused by the heavy metal content of race pads... so anti-squeal isn't going to help *much*.

Anyway, I think there is something very wrong with your right rear brake... it's a nd not the aggressive pads.

 

Try checking the e-brake setting to make sure it's not activated when it's not supposed to be. My friend also has this strange rear brake caliper issue that the dealership can't figure out (not a surprize, ******* MCM service ). He uses stock brake pads, and I also feel the pads have nothing to do with it.

 

I'm not sure what kind of antisqueek compound you are using. But you may try this. If you are using the aerasol, or the simple anitsieze paste. That doesn't work so well. Get some of the silicone bases glue stuff. Remove the pads, get some 100 grit sand paper, lay the sand paper flat on the work bence and sand the pad flat until it's all scuffed, and rough looking, no shiney area. Then on a grinding wheel really chamfer the edges, 45 deg. Smear the sqweek goop on the back of the pad.
Now the rotors. If you did not machine them, or use new ones, The new pads that you used most likely never made a full proper contact on the rotor. So you may have ran them on the track making only about 30% pad contact. Which really over heats them. When you over heat them like that, the binder material, (the glue in the pad) gets scorched on that limited contact area. So you need to grind past that suface area. If you rotors had more than 10000 miles, the rotors were not flat, they looked flat, but there were concave. You need to either machine them flat or give them enough time to conform to the deformed rotors.
Most of the time if you do these steps the noise will go away.