How can you tell if brake pads & discs are worn out?
Discussion
Right, looking for some help from the PH collective 
Not knowing much about how cars work, can someone tell me if there is an easy way to see how worn my discs and pads are?
The garage has said both front discs and pads need replacing, however alarm bells started ringing when the phrase "your pads are 95% worn" was used, something I read on here years ago.
The car is an 07 Aygo and it's just had a 30K service.
Cheers
Not knowing much about how cars work, can someone tell me if there is an easy way to see how worn my discs and pads are?
The garage has said both front discs and pads need replacing, however alarm bells started ringing when the phrase "your pads are 95% worn" was used, something I read on here years ago.
The car is an 07 Aygo and it's just had a 30K service.
Cheers
Around 3mm of pad on each side and its time to start thinking of a new set. Discs usually should last around 30k - 50k depending on how hard your pads are.
If you have any shaking when braking then discs are warped. Mine went recently because they were worn.
If you have any shaking when braking then discs are warped. Mine went recently because they were worn.
Edited by boyoM3 on Thursday 16th July 15:45
Wheels off, if you can see the pads then you should know. They usally have a wear grove in the middle, thats the first thing (If your still not sure pop in to halfrauds and have a look at a new set of brake pads, this will then give you the comparison you require). Second put some vernier calipers accross the disk and measure its thickness. Then all you have to do is ask your local dealer (or look in the hand book) what the minimum thickness of the discs are before changing.
Its a good way of making money for some people......
oh and finally, hwo do your brakes feel? If they are as they alwasy where then worry not. Grumbeling and pulling to one side when braking can indicate worn/sticking pads calipers...
Its a good way of making money for some people......
oh and finally, hwo do your brakes feel? If they are as they alwasy where then worry not. Grumbeling and pulling to one side when braking can indicate worn/sticking pads calipers...
at 30k your discs should not be worn out unless you're one of those people who drive along on an open road and brake for no reason other than to check the pedal is still there. Pads, hmmm could be but shouldnt on your type of car.
Anyway to answer the question, look down through the spokes of the car, you will see the calipers, the pad is inside there, new pads have about 10-15mm of ferodo (the pad) on the disc side of the plate that holds them in place.
this image shows what i would say is about half worn pads.
You can take the wheels off to do this but i wouldnt.
if the discs are worn the 2 pieces of steel will be very thin or have a huge step near the top and bottom, you'll be able to feel this with your finger.
Anyway to answer the question, look down through the spokes of the car, you will see the calipers, the pad is inside there, new pads have about 10-15mm of ferodo (the pad) on the disc side of the plate that holds them in place.
this image shows what i would say is about half worn pads.
You can take the wheels off to do this but i wouldnt.
if the discs are worn the 2 pieces of steel will be very thin or have a huge step near the top and bottom, you'll be able to feel this with your finger.
Edited by WorAl on Thursday 16th July 15:41
Without taking the wheels off, finger through the wheel to the edge of the disc. Is there a lip? Finger between the the metal of the pad and the disc. Is this low?
This only checks the outer faces of your discs, however putting the car on lock will enable a quick check the other side.
This only checks the outer faces of your discs, however putting the car on lock will enable a quick check the other side.
I'll be amazed if the Aygo doesn't have a light which illuminates on the dashboard if the pads reach sufficient wear to need changing. Have you read the driver's manual?
Visual check of pads with wheels removed is never a bad thing but doesn't tell you a great deal without knowing what the manufacturer recommends and what the pads looked like when they were new.
Disc wear is again all a matter of the manufacturer recommendation and needs careful measurement, but you can get a rough idea by feeling the disc to see if there's a noticeable "lip" where the pads run on it.
There should always be a good safety margin because if the worst happens your pads can be ejected in extreme wear situations (usually needs both pad and disc to be totally knackered) and then your car has no brakes at all, which is a bad thing....
Visual check of pads with wheels removed is never a bad thing but doesn't tell you a great deal without knowing what the manufacturer recommends and what the pads looked like when they were new.
Disc wear is again all a matter of the manufacturer recommendation and needs careful measurement, but you can get a rough idea by feeling the disc to see if there's a noticeable "lip" where the pads run on it.
There should always be a good safety margin because if the worst happens your pads can be ejected in extreme wear situations (usually needs both pad and disc to be totally knackered) and then your car has no brakes at all, which is a bad thing....
Well if you're comfortable getting the wheel off, you're 80% of the way to changing the pads, it really is an easy job that dealers love charging lots for. Changing discs requires minimal effort on top.
As said, if the pads have less than a few mm left, then you should change them. Make sure you check the inner pad, as on single pot sliding caliper brakes it will wear more quickly. DO NOT rely on a finger check of the outer pad.
As said with discs you need to find out the minimum thickness, but a good indication is a significant lip around the outer edge.
Also as said, if the pads have lasted 30k I'd be surprised if the discs had had it as well. I'd expect a set of discs to last longer than that.
Edited by The Wookie on Thursday 16th July 15:53
There a few videos on YouTube that give you a bit of an idea - this ones not too bad, but DON'T turn the steering wheel of the car unless you've got both sides up on axle stands!
http://www.youtube.com/watch?v=CFFd3TCxC80
(rotor is American for brake disc)
http://www.youtube.com/watch?v=CFFd3TCxC80
(rotor is American for brake disc)
The Wookie said:
Well if you're comfortable getting the wheel off, you're 80% of the way to changing the pads, it really is an easy job that dealers love charging lots for. Changing discs requires minimal effort on top.
As said, if the pads have less than a few mm left, then you should change them. Make sure you check the inner pad, as on single pot sliding caliper brakes it will wear more quickly. DO NOT rely on a finger check of the outer pad.
As said with discs you need to find out the minimum thickness, but a good indication is a significant lip around the outer edge.
Also as said, if the pads have lasted 30k I'd be surprised if the discs had had it as well. I'd expect a set of discs to last longer than that.
Edited by The Wookie on Thursday 16th July 15:53
Actually, on the Focus the caliper mount bolts are really easy (lucky as IIRC they're those rubbish Torx heads), and then of course the disc just comes straight off, I'd expect the Aygo to be similar, especially as it's a newer car
Evo not so easy, but still cured with 1 expendable ratchet, both hands around suitable structure to brace, and a well placed foot on the end of the handle
Alternatively you could jack it up a bit more and use a longer spanner
Evo not so easy, but still cured with 1 expendable ratchet, both hands around suitable structure to brace, and a well placed foot on the end of the handle
Alternatively you could jack it up a bit more and use a longer spanner
There are a few examples of worn out discs (and other horrors) on here
http://tinyurl.com/lyz2vw
(specifically Horror of the Week 28/05/09)
I'd suggest not letting them get to this state
http://tinyurl.com/lyz2vw
(specifically Horror of the Week 28/05/09)
I'd suggest not letting them get to this state
Edited by Orb the Impaler on Thursday 16th July 16:21
Many discs these days have a wear indicator on them - it's a semi-circular 'imprint' on the outer edges of the disc itself. Once the wear surface breaks the circle then the disc is worn-out.
Look at the picture below and you'll see what I mean, there's no real need for calipers or any fancy stuff.
Be very wary of looking for a lip on the edge of the disc as that can be misleading.
Pads are simple, as has been mentioned.
I would expect a pair of front discs to go through two sets of pads these days before they need replacing.
Look at the picture below and you'll see what I mean, there's no real need for calipers or any fancy stuff.
Be very wary of looking for a lip on the edge of the disc as that can be misleading.
Pads are simple, as has been mentioned.
I would expect a pair of front discs to go through two sets of pads these days before they need replacing.
Edited by Ranger 6 on Thursday 16th July 16:42
Mr_Yogi said:
The garage has said both front discs and pads need replacing, however alarm bells started ringing when the phrase "your pads are 95% worn" was used, something I read on here years ago.
Garage has a lack of work on. Hence you needing new discs.The chances are that your discs are absolutely fine. I have a Doblo on an 06 plate with 65k on the clock and the discs are beginning to get to the point of being changed, but I still reckon I've got another 15k on them yet. Your 30k is nothing.
Chances are your pads are also fine. You will feel when your pads are shot, because you will literally hear a graunching noise of metal on metal. Also, the brakes will feel a bit crap.
As other people have said, take the wheel off and have a look for yourself. The pads should have loads of material on them. As for the discs, unless you drive the car like you stole it, I cannot see how you would need new discs yet.
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