Need advice: Brake pad squeal on my BMW 3GT

I experience a whining noise while braking at slow speeds.

BHPian Shubhz recently shared this with other enthusiasts.

Anyone experienced a whining noise while braking on the F34? Particularly when braking on slow speeds like as in approaching a speed bump or while negotiating a curve? I was facing this issue. SA said it may be because of brake pads.

Subsequently the front pads were changed, callipers greased and oil bled.

Things were alright for a couple of thousand kms and now that sound is back.

Kilometers run - 25,000

Video of the brake noise

Here's what BHPian DRIV3R had to say on the matter:

This sounds like brake squeal. A dab of anti squeal paste on the rear backing plate of the brake pads and contact area of pad with caliper should fix it.

Here's what BHPian Kosfactor had to say on the matter:

No matter what you do, it will start again if you do a Mysore to Ooty through Masinagudi

This video is the official explanation about that sort of noise.

Here's what BHPian sagarpadaki had to say on the matter:

Apply the above paste as a film on the back of brake pads. If the pads come with anti noise shims, remove the shim and apply the paste and put the shims back on. This should eliminate any noise caused due to pad vibration during braking.

Refer this video for how to.

Here's what BHPian Jeroen had to say on the matter:

Vibration is a function of mass, so lots of dirt build up might chance the resonance frequency a bit. Over time discs wear down and loose a considerable amount of their mass and thus resonate at different frequency.

Part of the Squeal can be coming from the piston on the back of the piston, and or the sides of the pad. So applying some copperslip or ceramic paste might get rid of it.

On my Jaguar I get these squeals very very occasionally. I have found that certain pads make it worse, or better. My current pads rarely give me any problems. And it can be fixed by taking the pads off, cleaning everything and remounting them with copperslip on the appropriate touchpoints.

What also might help is to very lightly file down the spots on the calliper where the side of the pads touch. The idea being the smoother the surface the less friction and the less likely something will make anodise when resonating.

What is important and relevant is of course, there is absolutely nothing wrong with your brakes when this happens. It is just annoying, and you can to a good extend minimise it. Most brakes don’t squeal, so there is hope!

Here's what BHPian androdev had to say on the matter:

Better to stop worrying about it. This is a very common issue with cars having big brakes. I too face this issue (brake noise when coming to a slow stop - like approaching a toll gate) and learned to live with it after few futile attempts to get it fixed.

Based on what I read, you can't have all these in a brake pad: dust-free, high-performance, quiet, long-life. My hypothesis is that OEMs prioritise performance and long-life over other two.

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