Squeak from brakes ~ cause/fix?

Discussion in 'Cars, cycling and transport' started by PaddyBloggit, Nov 28, 2016.

  1. PaddyBloggit

    PaddyBloggit Frequent Poster

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    I have a terrible squeak from brakes when coming to a stop.

    It happens in the morning usually. To a lesser extent in the evening after work (if at all).

    Car is always garaged. Brake pads are ok.

    Car was serviced at the start of November. Pads didn't need replacing. Mentioned it to garage.

    They said water might be a cause. This can't be the case as the car is often garaged for a number of days (I also drive a 4x4). Car hasn't seen any water/rain or a washing for awhile.

    I even tried cleaning around the discs/pads with compressed air.

    Any idea what's up? Any suggestions as to a solution?
     
  2. noproblem

    noproblem Frequent Poster

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    Sounds like an ould fella who'd be couched for too long, then gets up after a few days to get as far as the fridge for some food and the movement wouldn't be too good nor the sounds coming out of him either. Often find that if he's sent off out the road for a good trot it wouldn't take too long for a lot of the oh's and ah's to go away. A bit of Savlon in the right places might work wonders for your car as well as more frequent use.
     
  3. dub_nerd

    dub_nerd Frequent Poster

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    Had a brutal similar problem years ago. I was told it was caused by dust, but as the OP says, blowing with compressed air didn't fix it. Not sure if there is a cure.
     
  4. PaddyBloggit

    PaddyBloggit Frequent Poster

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    ?
     
  5. Brendan Burgess

    Brendan Burgess Founder

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    :)

    I no the feeling, but it's probably not much help to Paddy
     
  6. PaddyBloggit

    PaddyBloggit Frequent Poster

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    Tis annoying especially when serviced to date and all appears to be in order.

    I've never had this issue with any other car I've had ... wet day or not.
     
  7. aprentice

    aprentice Registered User

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    If there's 1 thing you shouldn't take advice from the internet on
    It's brakes if your unsure you should have a pro look at them but my tuppence worth ....
    Would be to try a bit of copper grease on the BACK of the pads it could be the caliper pots rubbing the back of the pads
     
  8. venice

    venice Frequent Poster

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    Cheap brakepads?
     
  9. PaddyBloggit

    PaddyBloggit Frequent Poster

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    I hope not. It's serviced by a Mercedes main dealer.
     
  10. PaddyBloggit

    PaddyBloggit Frequent Poster

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    I'm only on the net because the garage told me pads were ok and all looked fine.

    Exasperation has driven me to ask for ideas as to possible solutions.

    I'll try the copper grease. Anything is worth a shot once.
     
  11. PaddyBloggit

    PaddyBloggit Frequent Poster

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    From wikipedia (always taken with a pinch of salt):

    "Sometimes a loud noise or high pitched squeal occurs when the brakes are applied. Most brake squeal is produced by vibration (resonance instability) of the brake components, especially the pads and discs (known as force-coupled excitation). This type of squeal should not negatively affect brake stopping performance. Techniques include adding chamfer pads to the contact points between caliper pistons and the pads, the bonding insulators (damping material) to pad backplate, the brake shims between the brake pad and pistons, etc. All should be coated with an extremely high temperature, high solids lubricant to help reduce annoying squeal. This allows the metal to metal parts to move independently of each other and thereby eliminate the buildup of energy that can create a frequency that is heard as brake squeal, groan, or growl. Cold weather combined with high early-morning humidity (dew) often worsens brake squeal, although the squeal generally stops when the lining reaches regular operating temperatures.


    Dust on the brakes may also cause squeal and commercial brake cleaning products are designed to remove dirt and other contaminants.


    Some lining wear indicators, located either as a semi-metallic layer within the brake pad material or with an external "sensor", are also designed to squeal when the lining is due for replacement. The typical external sensor is fundamentally different from the noises described above (when the brakes are applied) because the wear sensor noise typically occurs when the brakes are not used."


    I've decided to call to another mechanic to get brakes checked again.
     
  12. mathepac

    mathepac Frequent Poster

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    If you've ruled out wear on pads or discs (no drums I assume), brake dust, rust on the discs, lack of lubrication between the metal contact parts there is a remote possibility that a piece metal (screw, nail, washer) stone or pebble is trapped between a pad and the disc. Does the sound seem to emanate from one corner?
     
  13. daithi28

    daithi28 Frequent Poster

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    Yes, I've had this problem before. Horrendous squealing when slowing down. The squeal is cause by resonance/vibration between the brake pad and the caliper. As others have said you can apply copper grease to the back of the pad which may reduce the squeal. Another option is anti-squeal brake shims or "champfer pads" mentioned above.

    I had shims made up for me by a local engineering workshop. They laser cut two pieces of stainless steel to the same shape as the back of the brake pad and punched the two pilot holes for the pins. They then sanded back the edges. I think they charged me €20 for the set. They took about 10 mins to make!

    I never had a squeak again!
     
  14. PaddyBloggit

    PaddyBloggit Frequent Poster

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    Local garage going to apply copper grease or equivalent. I'll see how that's goes before we go looking at engineering options.

    Thanks to all who responded.