Help me diagnose a brake poblem? 2003 Buick

I'm trying to diagnose a problem with a relative's car via long distance.
She often does not drive for 2-4 days at a time. When she first drives it after
a few days' idle time, there is a loud grinding/scraping noise (not a squeal) from one or both rear brakes when they are first applied. After a couple of brake applications the noise "goes away". The longer the car sits idle, the worse the noise is.
She does not want to go to the dealer again (she's already been twice) without some idea of what to look at. The dealer is liable to give her a story about how he can't diagnose it unless it's misbehaving right under his nose.
thanks...
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    If its got rear drums... its probably just rust on the shoes from sitting... I know on alot of safari vans, the first time you apply the brakes after sitting awhile the rears tend to lock up. Not sure if this happens with rear discs as much or not..
Doghouse Riley wrote:

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Doghouse Riley wrote:

The reason that the dealer will give her that story is because it's correct. Maybe you can tell me how to diagnose a problem that is not occuring when you look at the vehicle? I'd love to know this, I'd probably make a whole lot more money and be considered a diagnostic "god".
The problem you describe is common. What we usually find is that there is an excessive amount of brake dust in the rear drums (if it has drum brakes) that causes the noise. Clean out the dust and try it again.
Ian
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shiden_kai wrote:

I have experienced similar effects from a rear disc brake system too, is that the parking brake shoes in the inner drum , or is it truly possible to be hearing the rust scraping from the outer edge of the rotor if car has sat unused for a month or so? Then if you know for sure I have another teaser I'd like help with.
Dan H.
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"Doghouse Riley" wrote: > She does not want to go to the dealer again (shes already been > twice) without > some idea of what to look at. The dealer is liable to give her a > story about > how he cant diagnose it unless its misbehaving right > under his nose. > > thanks...
Sounds like she doesnt use the car that much. Why not leave it at the dealership for a few days?
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distance.
drives it after

squeal)
couple of

idle, the

without
story about

Rust in/on the rear brakes, VERY common if the vehicle sits for a while, or if it rains overnight. Usually occurs due to the metallic dust (both from the shoes/pads and from the wear on the disc/drum) getting damp and rusting. One thing to watch out for is that the pedal doesn't start to pulse from the rust build up. That is a sign that the brake drums or rotors have an area of rust burnished on them. If that happens just have them turned or replace them.
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