Yep... scour the brake rotor with emory sandpaper... medium or course... so
it look all scruffed up. Then break in that pad again as specified.
From 40MPH... slow the car down very gently to 30MPH... wait 30 sec...
repeat again for 3 more time and you are done.
Brake squeal can be caused by several things. One common problem is a
"crystallized" pad surface. This happens when the pads have overheated
during the break-in period, which is usually caused by putting new pads on a
worn rotor without first knocking-down the shine on the rotor, or by pads
are not secured to the caliper (either with a good system of clips or break
paste) and allowed to "chatter". The symptom is usually that moderate pedal
pressure causes the squeal, but full or very light pressure will silence it.
The easiest way to resolve this problem is to "knock-down" both the rotor
and the pads. That is, to sand them emery paper so that the shine is gone.
This will provide a new surface for a new break-in period. It is also very
important that the pads are secured to the caliper to they cannot chatter.
Some modern disc brake systems use clips that secure the pad quite well, but
others just have pads that snap into place. If the pad, once attached to
the caliper, can be shifted around by hand, then brake paste should be used
to secure it.
Brake dust can cause noise if it contains a high amount of metal particles
and is allowed to build-up on the pads. This can generally be solved by
cleaning the brakes with an appropriate solvent. Some pads are worse about
this than others. OEM MBZ pads tend to create a lot of dust, but rarely
have a high metal particulate content to cause this problem. Another cause
of squeal is that a large piece of metal in the metallic pad becomes exposed
as the pad wears. Technically, this would be a defect in the pad, but it's
rarely worth the trouble to replace it because it will generally go away as
it continues to grind on the rotor.
Squeal mainly come from the tiny gap between the rotor and the pad... when
pads are not properly broken in...When you put new pads on and glazed it...
it make the pads hard and won't properly mate to the existing rotor surface
contour... hence the "gap"... sort of like a whistle.
Both replies interesting. I had squeal when my car was newer (can't
remember the mileage, now 18 000). Merc claimed to have put some sort of
paste in but squeal returned. Now it seems to have gone without further
For direct contact replace nospam with schmetterling
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