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Albert27

Basic question on brake pads/discs.

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Hi guys,

Was working on the car today changing the drive belt and while i had the wheel off wanted to look at my brake pads.  Looking from the top down view the inner pad seemed a lot thinner on both wheels than the outer.  However when i looked from beneath through the little window in the caliper they seemed both the same size so no uneven wear.  Am I looking at brake pads from below or have i made a mistake?  Or is the view of the pads from the top obstructed by something which is why they're appearing so thin on the inner?    Apologies for the very basic questions but this is new to me.

Secondly, when should the discs be renewed?  What is the minimum thickness or is there anything i should be looking for to signal replacement?  It's a focus mk 2.5.

Thanks in advance.

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View from the top can give the illusion they're thinner due to the way light bounces but they could be wearing uneven best way to check would be take them off and measure up or try measure up with them still on, as for when your brakes will need renewing I always say when they start to feel rubbish, after all they're the only thing stopping you. 

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They look okay to me, does the disc have a lip? depending on the size of the lip that would be a good assumption they need replacing.

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2 minutes ago, Ryan_Tango said:

They look okay to me, does the disc have a lip? depending on the size of the lip that would be a good assumption they need replacing.

Thanks Ryan.  When you say lip, what exactly do you mean? 

 

9 minutes ago, Ryan_Tango said:

View from the top can give the illusion they're thinner due to the way light bounces but they could be wearing uneven best way to check would be take them off and measure up or try measure up with them still on, as for when your brakes will need renewing I always say when they start to feel rubbish, after all they're the only thing stopping you. 

They feel ok to me....the only thing i have noticed is a grinding type noise when I first apply brakes after the car has been sat a while.  Then no noise at all.  Is that normal?

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2 minutes ago, Albert27 said:

Thanks Ryan.  When you say lip, what exactly do you mean? 

 

They feel ok to me....the only thing i have noticed is a grinding type noise when I first apply brakes after the car has been sat a while.  Then no noise at all.  Is that normal?

Sounds like it's just rust scraping off it's normal until it does it all the time.

 

As for the lip lip.jpg

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5 minutes ago, Ryan_Tango said:

Sounds like it's just rust scraping off it's normal until it does it all the time.

 

As for the lip lip.jpg

Now I've got it!

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2 minutes ago, iantt said:

look ok to me also. my pads are far thinner than that. lol

lol Thanks Ian, are you basing that off the second picture from beneath?  

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based on all pictures. what we cant see is the inner face of disc but if its simular to the outer face then there ok for now. i will give you the specs .

new brake disc thickness 25mm.  worn minimum thickness 23mm

pads minimum thickness 1.5mm. but i personally wouldnt go that low.

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15 hours ago, iantt said:

based on all pictures. what we cant see is the inner face of disc but if its simular to the outer face then there ok for now. i will give you the specs .

new brake disc thickness 25mm.  worn minimum thickness 23mm

pads minimum thickness 1.5mm. but i personally wouldnt go that low.

Thanks. I just wanted to make sure I was looking at the brake pads from below (second picture) !  I think i'll take them out and have a good look at them, more so for the practice than anything. The inner pad on both ain't visible in the pics from top down and they both looked really thin so i guess to be on the safe side i'll measure them up & look for uneven wear I've noticed in haynes it says there's a risk of asbestos and to use a mask. I thought asbestos was only on old things! Is this accurate or are they being over safe?

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While you've got them out check the inner face of the discs. Corrosion can migrate outwards from the centre. This seems to be more prevalent on the inside face for some reason and reduces the effective area in which case they should be replaced.

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On 21/01/2017 at 5:30 PM, iantt said:

based on all pictures. what we cant see is the inner face of disc but if its simular to the outer face then there ok for now. i will give you the specs .

new brake disc thickness 25mm.  worn minimum thickness 23mm

pads minimum thickness 1.5mm. but i personally wouldnt go that low.

Hi Ian, Shortly going to measure the thickness of the discs with a micrometer.  Just to clarify, does the measurement include the small gap between the discs?  

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TBH they look a bit worn to me .The price of changing  out the the disc's and pads are small why bother measuring the discs ,if you are worried change them out for peace of mind it's easy enough not so good in this cold weather though lol

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5 hours ago, Albert27 said:

Hi Ian, Shortly going to measure the thickness of the discs with a micrometer.  Just to clarify, does the measurement include the small gap between the discs?  

yes

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